- Creating Your Own Rooftop Garden
- How to Make a Rooftop Garden
- Choosing a rooftop garden design scheme
- Choosing the best flooring material for a rooftop garden
- Choosing a planting scheme
- What you really need to know about creating a roof garden…
- It’s not all about the weight…
- There’s also planning permission…
- Think about access to water…
- You need to consider your neighbours’ privacy
- Speaking of screening…
- Roof garden furniture – the important considerations
- And think about storage
- Roof garden pots
- Best plants for roof terraces
- What about accessories?
- Flooring for a roof garden…
- So why have a roof garden?
- Rooftops are great for growing fruit and veg…
- Starting a Rooftop Garden: A Basic Guide for All Level Gardeners
- Starting a rooftop garden? Why not?
- Starting A Rooftop Garden: Find and Study Local Rules
- Seek the Advice of a Contractor
- Prepare Your Environment
- Sunlight Exposure
- Drainage and Waterproofing
- Gardening How-to Articles
- Start a Rooftop Container Garden
- Rooftop Garden Guide
- Can I have a garden on my rooftop?
- GET AMBER’S CHECKLIST FOR DESIGNING ROOFTOP GARDENS
- How can the weight be kept down?
- What utilities are required for a rooftop garden?
- What are some important safety considerations for rooftop gardens?
- How can views, both good and bad, be handled?
- What types of plants are best suited for rooftops?
- What features can be incorporated into a rooftop garden?
- Are you growing a Terrace Garden? If yes then this informational guide on ‘Terrace/Roof Garden Plants’ will surely help you in choosing the plants for terrace garden.
- Terrace Garden Vegetables
- Terrace Garden Flowers
- Plants for Terrace Herb Garden
- Low Maintenance Succulents and Perennials
- Shrubs, Dwarf Trees and Vines
- Pay attention to the choice of containers
- Rooftop Garden Plants Must Withstand These 2 Things
- Key Characteristics Many of the Best Roof Garden Plants Share
- The Importance of Hardiness Zones for Rooftop Gardens
- Diverse Plants for Rooftop Gardens
- How to Water Rooftop Plants
- What Type of Planters Should You Use for Rooftop Gardens?
Creating Your Own Rooftop Garden
In more urban areas, a gardener is limited in the amount of space that they have. If you find that you are running out of room, or if you want an outdoor living space, then things may be looking up for you, literally. You may want to consider creating a rooftop garden. Rooftop gardens are an ideal way for an urban gardener to expand their space. Rooftop gardens also make good use of frequently unused and wasted space.
There are, however, a few things to keep in mind when creating a rooftop garden.
How to Make a Rooftop Garden
First of all, find out how local ordinances, rental property rules or home owner association regulations view a rooftop garden. Rooftop gardens may be prohibited or require special treatment and it is always best to know these things before you spend time and money.
Second, get an architect or contractor involved as soon as possible. You don’t need the architect or contractor for the whole garden building process, but you will need them to tell you if the building is safe to build a rooftop garden on. Some buildings were simply not designed to withstand the additional weight a rooftop garden would add. Other buildings may be able to take the extra weight but may only be able to take a limited amount of weight. An architect or contractor should be able to tell you if this is the case with your building.
Third, even if your building can structurally take the extra weight, the weight of your rooftop garden should play a role into your design. Try to use as little weight as possible. Use plastic, fiberglass or foam planting containers and avoid using pavers. Use lightweight potting soil rather than garden dirt. Use Styrofoam peanuts for drainage rather than rocks or pottery shards.
Fourth, keep in mind that your rooftop garden will be considerably windier than a normal garden. You will need to incorporate windbreaks into your rooftop garden design. Try using trellises or some other latticed windbreak for your rooftop garden. Windbreaks that disrupt the flow of the wind, rather than trying to stop it completely, are actually more effective. Solid windbreaks are more likely to be knocked down by high winds than ones that allows some wind flow. Plus, you really don’t want to eliminate wind flow. You just want to decrease it.
Fifth, think about how you will get water to your rooftop garden. Your rooftop garden will need to be watered frequently in hot weather and lugging heavy buckets of water to the roof is not fun or practical. Consider either having a water storage system built in or having an automatic watering system installed.
If you keep these things in mind, you will find that your rooftop garden can provide a lovely and great place for you to escape to.
Taller wind-tolerant shrubs offer some protection. Think of them as a living screen. Tough evergreens such as Olearia, Phormium, Pittosporum and Spotted laurel in big tubs are perfect for the job. Bamboo is worth trying too, except on very windswept roof terraces as its large leaves sway too much in the wind, which means the roots will shift about and the plants won’t establish in their new pots.
You’ll need protection from sunshine too. Shade sails are excellent – again, wind-porous materials are the best choice as you don’t want a solid barrier, with the risk of the fabric tearing or flying away. A cheaper solution is to put up a parasol, but make sure it’s securely anchored, otherwise strong gusts might blow it away.
Choosing a rooftop garden design scheme
Sleek and simple is the golden rule when designing a rooftop garden. Cottage or rustic themes rarely work. Go for a simple, linear layout with contemporary materials such as polished stone, rendered walls, Cor-Ten steel or concrete, or traditional ones such as woven hazel and clay pavers using them in a modern way. Choose materials to complement patterns or colours in the surrounding landscape or adjacent buildings so the design blends in.
Whatever layout you choose, take account of the view. Eyesores like gas towers and motorway flyovers will need to be subtly screened, but if you have a sea view or attractive cityscape, make the most of it in your design. Organise your area to maximise good views, maybe framing them with tall container plants or pencil junipers.
Outdoor lighting can be a very effective addition to a rooftop garden design scheme. Plan your lighting with the specifics of the rooftop location in mind, avoiding designs that are lightweight and flimsy, as they will most certainly be ripped off by strong winds. Consider built-in wall lights instead; if you still want the dreamy ambience of fairy lights, choose ones that are on the heavier side, and position them in a sheltered corner above seating, or attach them to a wall.
Get more tips on how to plan your garden lighting.
Different types of outdoor lighting are used to create lit-up zones as part of the Lakeview Rooftop + Garden project by dSpace design studio
(Image credit: dSpace Design Studio)
Choosing the best flooring material for a rooftop garden
Choosing the flooring material for your rooftop garden can be approached in much the same way as choosing flooring for other outdoor spaces; the choice should be dictated by the size and style of the space, as well as your personal preference. Stone or terracotta paving will work in smaller spaces – tiles are your best bet for ease of transporting on to the roof and installation.
Read our guide to picking the best paving for your garden for more.
Decking is a good choice for a roof terrace or balcony because it’s warm underfoot, easy to work with and lightweight for carrying up several flights. Any joists can be fixed to surrounding walls so the weight gets distributed to the walls and not solely to the roof itself. Choose western red cedar or hardwoods such as ipe or balau (from a sustainable source). They retain their colour, last much longer than softwood decks and look better too. If your roof terrace abuts a room with wooden flooring, use decking of a similar colour to .
Up for a DIY challenge? Find out how to install decking. And find out how to design a deck to get the look right.
Most roof terraces are covered in a waterproof membrane, while others have a fireproof layer, so be careful not to puncture them with fixtures and fittings.
Decking is used as part of the stunning Lakeview Rooftop + Garden project by dSpace Studio
(Image credit: dSpace design studio)
Choosing a planting scheme
Plants will have to be very tough to cope with difficult conditions. They’ll probably have to be tolerant of high winds and drought as well as strong sunshine or deep shade, depending on the aspect. Dense evergreen plants are good for year-round interest and most have thick, glossy leaves, which prevent them from drying out quickly. Griselinia, Garrya, Viburnum tinus, Escallonia, Euonymus, Fatsia and dwarf fan palms are ideal and provide shelter for colourful-but-tough perennials such as globe thistles, day lilies and Heuchera tucked underneath them.
On open roof terraces, plants must be able to cope with blazing sunshine. Choose plants such as thyme, lemon balm, sage, lavender, Potentilla, Olearia, Caryopteris, Californian lilac and dramatic Yuccas and Agaves. Grasses like hot conditions so they’re a good option as they create subtle texture. Miscanthus (try ‘Morning Light’ or ‘Flamingo’) are robust and stand tall; or for very exposed sites, choose Carex and Festuca varieties which form tight, low clumps.
Dwarf conifers, like pencil junipers and Pinus mugo ‘Mops’, tolerate hot, exposed sites too and couldn’t be better suited to roof terraces or balconies.
Alpines, whose natural habitat are clifftops and mountains, need little water and can bear extreme exposure to intense sunshine and strong winds. Place rows of terracotta bowls full of carpeting Sedum and Houseleeks – elegant and effortless.
Get more in-depth advice on how to choose plants for your garden.
A container garden on a rooftop terrace featuring Walk On Glass Rooflights by Roof Maker
(Image credit: Roof Maker)
- 10 ideas for small garden terraces and balconies
- 11 outdoor living space design ideas
- Container gardening for small spaces
What you really need to know about creating a roof garden…
I asked him what we need to know in order to create a successful roof garden.
Six floors up, with views of the Houses of Parliament, the ‘Walkie Talkie’ and the London Eye, shoppers can have coffee, drinks or meals in the John Lewis roof garden. You can book a ‘summerhouse’, and feel a million miles away from the bustle of Oxford Street below.
It’s not all about the weight…
The first thing that any of us think about when considering a roof terrace is ‘will the roof hold the weight?’
Unless you’re already living in a contemporary house with a purpose-built roof garden, Tony advises getting an architect or surveyor to establish what weight the roof can hold. And that doesn’t just mean the weight of pots, plants, soil and furniture.
‘People forget that you also have to include the weight of however many people will be on the roof at any one time. In the John Lewis garden, only a limited number of people can use the roof garden at any one time, because of the age of the building.’ (No wonder it feels so peaceful…)
But that’s not the only consideration…
The John Lewis roof terrace is large, but the number of people who can be there at any one time is restricted.
There’s also planning permission…
You might think that if you have a flat roof, and you know it’s strong, then you can take chairs and pots out there. Voila! Roof garden.
But you have to have planning permission for a proper roof garden, which will probably also involve building controls. Amongst the issues they will want to consider are how you get onto the roof garden. Will you have to climb through a hatch? And how will you stop people falling off?
Roof terrace walls need to be safe. Tony uses a solid barrier or glass walls because railings offer too much opportunity for children to climb over them. Container-grown veg do well on a roof terrace – it’s nice and sunny, though you need to protect them from the winds.
You’ll also need to consider how you get your roof garden building materials up onto the roof. ‘Luckily John Lewis had an old “carpet lift” from the days when people bought carpets in the store and took them away then and there,’ says Tony. ‘So we had a three metre high lift. Otherwise you’re restricted to whatever length or height of material that can go up the stairs or in the lift, unless you hire a crane.
Most of us do not have a useful carpet lift (carpet elevator, if you’re reading this in the United States). So remember access at the design stage!
Think about access to water…
Roof gardens are hot and exposed. Plants will need watering regularly, especially as they will be in pots.
Large wooden planters need less watering than lots of small pots.
‘If you’re having to struggle up a ladder and through a hatch with watering cans, watering will be difficult,’ warns Tony. ‘It’s really important to get a tap or irrigation system up on the roof for watering.’
You need to consider your neighbours’ privacy
A roof garden could be very invasive as far as your neighbours are concerned. Think about screens and where you’re going to look.
There weren’t many issues of privacy for John Lewis, because they are surrounded by shops and offices. But they did still need screening. Their neighbour to the left has a large neglected roof, with air conditioning units and other ugly detritus. ‘We put up a row of amelanchier trees and a hedge to screen that view,’ says Tony.
You can just see a dilapidated roof behind this bird box, but most of it is screened from view by hedging.
Tony created the John Lewis roof garden in 2013. ‘The London skyline has changed considerably since then. There’s lots of building, so although most of the hedging is fixed, we move pots around every year to block any ugly sight lines’.
Tony moves some planters around every year in order to block some of the building work – although I love this juxtaposition of a high modern crane and an old-fashioned milk churn.
Speaking of screening…
Screening is vital on a roof garden, because it helps reduce the windiness. But a trellis or a hedge is much better than a solid wall. Wind is broken up when it whistles through a hedge or trellis, but it goes up a solid wall then lands, still furious, on the other side.
Hedging screens some of the wind on the John Lewis rooftop. It isn’t very high hedging – not more than 5-6ft, which is enough to screen anyone sitting down, but not so high that it may get blown down. Note that the trees are pruned to have quite small canopies.
Roof garden furniture – the important considerations
You might think that roof garden furniture should be super-light.
But light furniture can also blow away more easily. ‘You need to make sure that furniture is fixed down when you’re not using it,’ says Tony. ‘For example, some people put dead weights on the top of chairs and tables when they leave the roof.’
Garden furniture (available from John Lewis). Because this roof terrace is a cafe, there are staff to make sure everything is safe and anchored at the end of the day – so there’s no chance of these garden benches landing up on top of the Number 73 bus in Oxford Street below –
but could you be so careful in your own home?
I blench at the thought of having to weight down garden furniture every time I leave a roof garden. Tony’s solution is to have garden furniture built in where possible.
And think about storage
‘People get excited about their roof gardens and buy 15-20 cushions,’ says Tony. ‘Then in bad weather, a bedroom becomes a dump because there’s nowhere to put them.’
This is another advantage of built-in roof garden furniture. Tony’s team design benches with internal plastic clip storage boxes, so cushions and other accessories can be stored in completely weather-safe conditions. ‘And they can’t be eaten by mice, either,’ he adds.
One of the delightful rooftop ‘summerhouses’ in the John Lewis roof garden. You can book one for your coffee or meal (like booking an ordinary table in a restaurant). Benches like these can be built to use for storage.
Roof garden pots
Like roof garden furniture, roof garden pots have conflicting issues of weight and stability. You probably don’t want to put lots of heavy pots on your roof garden, but if you put light ones they’re more likely to blow over (or away, if the winds are serious).
Low planters with herbs and annuals on the John Lewis roof garden. This sort of planting is more stable than having high pots and plants.
Tony’s first advice is ‘Don’t have lots of small pots. They dry out quickly and heat up, too. Go for large, sturdy pots.’ Sturdiness is about shape as much as anything – a tall pot or vase shape will blow over much more easily than a low or square shape.
Tony uses sheets of polystyrene or polystyrene balls in the pots to insulate them against wind and heat. It reduces the amount of compost you need to use, which also makes large planters less heavy. You can also buy ‘light compost’ for roof terraces.
Best plants for roof terraces
The best plants for roof gardens are those with small or narrow leaves, says Tony. Pines, for example, are good at withstanding exposed conditions and have needle-like leaves, so the wind will blow through them rather than blow them away. Low plants, too, are better than high ones.
Pines and grasses along the edge of the roof garden, plus a view of the London Eye.
What about accessories?
When Tony is called in to re-design a roof garden, he says he almost always ‘finds at least one smashed candle lantern lying on its side.’ Go for fitted lighting or lighting that’s easy to store. And if you have pretty displays, you need to find a way of securing them.
These pretty pots and accessories on a vintage ladder on the John Lewis roof garden are glued down to prevent them being blown away.
But you can close a door on this rooftop ‘summerhouse’ so that everything is safe. But most domestic roof terraces probably don’t have room for garden sheds or summerhouses. Tony advises something like a retractable sail for shelter.
There’s the top of a skyscraper reflected in the glass – if you peer closely.
Flooring for a roof garden…
If your aim in having a roof garden is to feel closer to nature, then artificial turf may seem inappropriate. But a real lawn wouldn’t be viable. Decking or artificial turf add a layer of insulation to any roof, so they are still ‘greener’ than having a plain flat roof.
Artificial turf on the John Lewis roof garden – planting and growing real grass just wouldn’t be viable.
The decking on the John Lewis roof garden is a composite decking called Millboard. ‘Wood decking doesn’t always wear well,’ says Tony. ‘It gets slippery with algae in winter, and splintery in summer.’ Millboard is a wood-free composite that is moulded from real wood patterns.
Once again, if you’re concerned about a green space being environmentally friendly, Millboard have had their carbon footprint verified by an independent body. They say it is about the same as a cup of latte.
So why have a roof garden?
I asked Tony what he was most proud of in the John Lewis roof terrace design.
‘I love people’s reactions – their surprise – when they first step into it. It’s a total escape from Oxford Street and the busy city.’ It is a genuine garden – although the themes are tweaked every year and pots are moved around – the hedges and trees have matured.
Roof gardens are also environmentally positive, because they help reduce the heat given off by roof materials. When it rains, planters and plants absorb rain, thus reducing run-off.
Roof gardens are a sanctuary for wildlife. Some of the John Lewis bird boxes are mainly decorative, but others have been placed under advice from experts. There’s a post here on what makes a good wildlife garden if you want to place bird, bat and bug boxes in the correct places.
The wildlife have enjoyed the garden: ‘We’ve even had a pair of ducks trying to nest here, presumably to get away from the crowds in Hyde Park,’ says Tony. This year, there’s a greater emphasis on native plants and wildlife-friendly planting to evoke an English country garden.
Rooftops are great for growing fruit and veg…
Roof gardens are usually sunnier than ground-level gardens, especially in cities (unless you’re surrounded by taller buildings that throw shade over your garden). So roof gardens are a great place to grow sun-loving plants like tomatoes, aubergines and herbs.
Herbs in the John Lewis roof garden. They’re used in cocktails, and in some of the restaurants. There have been unusual cocktails, such as a lavender cocktail or even one made with pine. I like the words…you could try a line of poetry, perhaps.
A roof garden is a lovely sunny place to grow strawberries, although the birds got most of these. I visited a garden in Melbourne, Australia where the owner maximised her space for growing food by using her flat garage roof for beehives and sun-loving plants.
For more ideas about roof gardens, see Tony’s book for the RHS (with Kay Maguire) Big Ideas, Small Spaces – 30 Creative Ideas for Balconies, Roof Gardens, Windowsills and Terraces. (Note: affiliate link, so if you buy through it, I may get a small fee)
The John Lewis Rooftop Garden is open from April to September (check website for specific dates and times). There are a variety of activities and workshops as well as the cafe/pub/restaurant.
And if you’d like inspiration from other gardens straight to your inbox every Sunday morning, then do enter your email at the top right of this page. Thank you!
- Permission: First, check with your landlord and/or building code. Questions about accessibility, building height restrictions, and fire regulations can prohibit any type of roof use.
- Structural Integrity: Make sure the roof can hold the load. Get a licensed pro to do this. Soil and pots are heavy to begin with and will get heavier as the plants grow. If you’ve ever tried to move a pot full of wet soil, you know how much weight water can add.
- Access: How are you going to get your materials and supplies in and out? If you live in an apartment, make sure you are allowed to use the elevator. Some municipalities require multiple access/exits and possibly exit lighting, fire alarms, and emergency lighting.
- Water: Will you be able to run a hose out to the roof? Watering cans can become a nuisance and containers require a lot of water. Consider installing a rain barrel and drip irrigation.
- Sun Exposure: Are you shaded by nearby buildings or the terrace above you? Even fun sun can be a problem when plants are sweltering on top of concrete.
- Heat: Besides the sun beating down on the roof, there is ambient heat being reflected from the roof surface, surrounding buildings, streetcars and metal exhaust and utility structures. You will probably want to provide some sort of shade, if not for the plants, then for you.
- Wind: Wind can whip down straight urban streets, especially on high-rises. You may want to consider some type of wall or fencing. If so, you will probably need to check your building code again for required heights and structural stability. This is especially important when building safety barriers for kids and pets.
- Privacy: Most rooftops are surrounded by neighboring buildings. If your rooftop garden will be in full view, you may want to plan for screening. You can plant a hedge of evergreens, run vines up a trellis wall or simply tuck under an umbrella table.
- Electrical Wiring: Electricity isn’t essential, but it sure makes things easier. If you are planning on enjoying your garden at night, candles aren’t the best lighting for weeding.
- Storage: There’s a lot of paraphernalia associated with gardening: tools, fertilizer, compost, buckets. Space is limited on a rooftop and it’s hard to camouflage a storage area. Shelves will suffice. Some rooftop gardeners opt for narrow closets. Another option is bench seating with built-in storage, to do double duty.
- Cost: Last but not least, how much are you willing to spend? You can start small and add on, buying more pots and plants (and soil) as you go. The real expense comes when you want to start hardscaping and building on the roof. Laying tiles or stone, building raised beds and boxes, adding lighting and furniture can all start to add up. Plus, you may need more structural work to support them.
Starting a Rooftop Garden: A Basic Guide for All Level Gardeners
Starting a rooftop garden? Why not?
When I was starting my urban garden, I found out I was soon running out of space. So I looked for other places around the house to grow my other vegetables. What I discovered was essential—I soon found out that I can actually grow some plants in the rooftop! Yes, starting a rooftop garden is convenient and easy. If you want to find out how to do it, read on!
You may want to consider creating a rooftop backyard. Rooftop gardens are an ideal manner for an urban gardener to broaden their space. Rooftop gardens also make use of typically unused and wasted space. There are, nevertheless, just a few things to keep in mind when making a rooftop garden.
Related: You don’t know where to start? Meet our experts to get Professional Guidance
Starting A Rooftop Garden: Find and Study Local Rules
First of all, find out how neighbourhood ordinances, property regulations or home ownership organization rules say about a rooftop garden. Starting a rooftop garden could also be prohibited or require certain rules and it is normally good to know these things before you spend your time and money.
Related: Starting a Garden from Scratch: Tips for Gardening Success
Seek the Advice of a Contractor
Get an architect or contractor as soon as possible in starting a rooftop garden. You don’t want the architect or contractor for the entire garden construction; however you will need them to tell you if the rooftop is safe and sturdy enough to construct a garden on.
Some buildings cannot resist the further weight that a rooftop garden would add. Different structures could take the additional weight but could be in a position to take a restricted amount of weight. An architect or contractor will tell you if you will be starting a rooftop garden in your building.
Prepare Your Environment
When you’ve established the area in starting a rooftop garden, there are some further environmental factors to keep in mind. Before outlining the form of your garden, consider sun and wind exposure on the roof.
First, you need to buy a few things before proceeding with the task. Pond liners may be used to prevent the roots, water or greenery from entering the roof. Making use of root membranes in the garden prevents the increase of weeds below the decking. They could also prevent dust from coming into the lower surface of the gravel and facilitate drainage. A moisture blanket might assist in maintaining the moisture in the soil. You also want to shop for the compost and the top soil which goes to be your plant’s nutrition. Finally, you need to buy those plants.
Next, you need to pour gravel. The gravel needs to be brushed into place and rolled over the foundation membrane. Now, pour on a few more gravel if you want a thicker layer.
Once the gravels are in place you want to spread out the moisture blanket. While doing this, make certain to leave 6-8 inches’ area around the corners. You can even make use of antique garments, towels and sacks as a moisture blanket considering they’re going to stay damp for a long time. Now, you need to pour another layer of gravel over the moisture blanket. Large portions of pebbles and gravels may unfold round the rims of the terrace. This would cause proper drainage and prevent the plant life from entering your home. Finally, make use of flashing tapes to connect the pond liner to the corners of your house. This will make sure that no water is going to get underneath the pond liner.
Now, let us go to making ready the soil for the garden. The first step is to unfold out the bark at the floor of your roof. Once the bark masking is complete, you want to start setting on the compost. Pour it first after which rake it around the entire surface. Similarly, pour on the top soil and rake it around. If you’re looking forward to a layer of soil, then you can strive stomping it down. Lastly, you need to install a few paved slabs so that you can without problems stroll for your lawn without treading on the plants.
Now, go to your nearby nursery and choose the plants which might be sufficient to live with little care. Let me give you the varieties of plants you can go for. Plants like Azure bluet, chamomile, sedum hispanicum, Sedum reflexum, thyme, misty butterfly, and blue haze arctic fire are good for a roof terrace. If you’re planting them deep, ensure to preserve the patches well so they can spread.
Definitely, sunlight shall be a major component in growing any sort of plant, so make certain you have a good concept of the daily and seasonal sun exposure and shade in your rooftop garden.
Also, sunlight exposure determines which vegetables, flowers, herbs, and veggies you would be able to grow. Most likely, rooftops acquire more direct sunlight, so if that’s the case, there are numerous choices based on the fact that most veggies develop well in full sunlight at a minimum of six hours with unobstructed, direct daylight.
Nevertheless, if you happen to live in a building that blocks sunlight in your rooftop, more vegetables that grow on shade such as kale, lettuce, and spinach will fare better.
Roofs may experience more windy conditions than conventional gardens. You should have a plan for wind protection, both for the garden and passersby below.
A rooftop garden with excellent airflow is satisfactory for most plants, but highly windy areas can dry out the plants or smash the stems before they are able to mature. Aside from broken plants, the final thing you need is for substances or instruments to blow off into the street beneath.
Related: How to Start Gardening At Home: 7 Best Tips
Drainage and Waterproofing
After you have deliberated out your garden’s measurement and dimensions, the next step is to ensure water resistant and prepare a correct drainage method.
Reducing corners on rooftop drainage and waterproofing is a big mistake. You could have a soggy garden with drowned roots and you could place yourself at risk for structural injuries.
You can set up a tapered layer of insulation to the rooftop to channel the extra water into a storage tank or drainage on the bottom. This may, of course, rely on your living conditions. It’s also wise to add a weatherproofed rubber layer. A pond liner may be used; however you can also spend money on a sturdier option like a rubber membrane.
Starting a rooftop garden required good methods: you can find ours in our Step by Step Garden Planner
Our tips are very useful to you as a gardener. Contact us now!
Featured Image from @brooklyngrange
A great way to garden outdoors when renting is to start a rooftop garden—a great solution for urban gardening. It’s a solution if the apartment building doesn’t have a backyard, or you can’t directly access one, because you’re renting on a higher floor. You can set one up for fun only, or you can produce food that is healthy to eat. Some flower varieties do well in a rooftop garden, so keep that in mind as well for cut flowers or for other uses.
You’re not going to want to start a rooftop garden on a roof that’s sloped. It should be flat, and one that you can safely access to water and take care of the plants. If portions of the roof don’t get full sunlight because other buildings are obstructing it, then choose a spot where you get the most sun. Before you get started, obtain written permission from your landlord, who might be concerned about liability issues with you making frequent trips to the roof.
Since you don’t own your apartment, your best option for rooftop garden is growing a container garden. Buy or find pots and other containers that have drainage at the bottom to release water. You’ll need to set the containers in something to catch the water that drains out, so that it doesn’t spill out on the roof.
Fill containers with soil, and you can buy potted soil mixes at stores that sell garden supplies or top soil from a nursery. If you want to grow an organic garden, be very picky about what soil you buy. You can buy organic potted soil online if it’s not available locally. Mix compost in the soil, even if it’s a soil mix. Your plants will appreciate the nutrients. Place the containers on the section of the roof that your landlord is allowing you to use for the rooftop garden. Transfer plants or seedlings when you get them.
Start Seedlings Indoors
You’ll have much better success if you start your seeds indoors, rather than starting them outside on the roof. Growing flowers and plants from seed is a longer process, but it’s cheaper. Some seeds require more work than others. For example, it’s better to sprout a pea seed before planting it, which involves more steps, than just putting them in potted soil. Learn how to germinate seed for the specific plants you want to grow. You may also need LED grow lights if you don’t get enough sun in your apartment. Controlling the temperature in your apartment is also important, since seeds like warmth when trying to grow.
An alternative to germinating seeds yourself is to buy transplants for your rooftop garden. Your local nursery or an online garden shop can sell you the plants you want, and all you have to do is transfer it, without shocking the plant. The way to do that is to water the plant first, and also to water the soil you’re transferring the plant to. Some transplants can stay in the container it came in for a little while, if you haven’t already set up the rooftop garden.
Once you get started, growing a rooftop garden is like any container garden. You may have to cover plants with tarp from time to time to protect it from heavy weather storms. Bringing the containers indoors is another way to protect plants during rain and hail storms.
Gardening How-to Articles
Start a Rooftop Container Garden
By Medi Blum | May 9, 2016
You can can transform a flat, tar roof into a lovely outdoor haven with container plantings. A well-planned rooftop garden can also provide habitat for local wildlife and mitigate storm-water runoff. Here’s what you need to know to start one of your own.
It goes without saying that in order to grow a roof garden, you must have a roof. But many city dwellers either rent or own an apartment in a shared building, and roof rights are not always included. Before you do anything else, be sure to check with your landlord, co-op board, condo organization, or building superintendent to determine what, if any, roof access you are granted.
If you skip this step and try to surreptitiously plant containers on your roof, you are likely to regret it. An angry landlord or super may drag all your hard work to the dumpster—or worse, you may ﬁnd yourself liable for damage or injury.
At the same time, learn as much as you can about the roof’s general condition as well as any upcoming maintenance requirements. This may be the year your roof is scheduled for repainting, for example. You don’t want to invest in expensive and hard-to-move planters or other structures that the roofers would have to clear away.
Once you’ve secured your roof space, assess the site just as you would when establishing a ground-level garden. You’ll also want to plan how to address various site challenges.
Sun and Heat
Make note of the site’s light exposure. Most roofs receive full sun (more than six hours of direct sunlight a day), but if yours is shaded by neighboring buildings most of the day, you’ll be better off growing shade-loving plants. If your roof is painted black, it will be signiﬁcantly hotter than a white or silver roof—black roofs in New York City can reach 170°F on a very hot day—and you’ll need plants that can survive such scorching temperatures.
Water Supply and Drainage
During the growing season, most rooftop container plants need daily watering, so a rooftop water supply is essential. Many gardeners use drip irrigation fed from roof-level spigots because of the intense watering needs of wind- and sun-exposed roof plants. If there’s no spigot, you could place a rooftop rain barrel on your roof, but before you do, take into account the weight of a full cistern, ﬁnd a secure place to put it, and clear it with your landlord or coop board.
If neither of these is an option, you may be left to haul watering cans up from your apartment. If so, it might be impractical to grow more than a few plants. Of course, succulents and other drought-resistant plants can go longer between watering and thus lighten your workload. No matter what type of plants you use, plan to place rubber mats, wooden decking, or some other buffer beneath your containers to help them drain more efﬁciently and protect rooﬁng materials.
It can be extremely gusty on a roof, especially if it’s unshielded by adjacent buildings. Take note of the areas that are most vulnerable to wind and plan accordingly. If your roof has no windbreaks, either install something to shelter your plants—like a well-secured trellis—or choose low containers that hug the perimeter walls. (Intake fans and air conditioning equipment are not good windbreaks to grow plants against—their heat output will scorch them and perhaps pose a ﬁre hazard.)
Wind-catching plants like trees are likely to topple over in high winds, especially if they’re planted in top-heavy, vase-shaped containers, so use square planters instead and position them against a windbreak. Unless they’re well sheltered and staked, long-stemmed ﬂowers will be battered, so consider growing shrubs and low-growing ﬂowering plants instead. Lightweight lawn chairs, gardening materials, watering cans and tools are liable to take ﬂight in windy weather (and possibly injure someone in the process), so be sure to completely secure all your rooftop furnishings and supplies.
Soils and Planters
No matter what you intend to plant, lightweight growing medium is a must for any rooftop garden to help reduce its overall load. Bagged soils marketed as container mixes, available at garden supply stores, tend to contain sphagnum, perlite, and vermiculite, which are lighter than garden soil and also help retain moisture and provide aeration.
Look for plastic or lightweight wooden planters and pots rather than heavier terra-cotta or concrete ones. Commercial sub-irrigated planters like EarthBoxes can be an especially useful option for rooftops. Also called self-watering planters, they contain reservoirs that can help stretch the time between watering.
Budget-conscious roof gardeners can make their own planters out of wide range of repurposed receptacles like children’s wading pools, plastic buckets, and recycling bins with holes drilled in the bottom for drainage. Some gardeners even have good luck with old coffee cans or heavy-duty plastic shopping bags. For vertical plantings, consider trellises, pergolas, or commercial hanging systems, like Woolly Pockets, that can be installed on walls.
Plant Selection, Maintenance, and Design Intent
Once you’ve assessed your roof site and planned your approach, the fun begins: You can now choose your plants. Drought- and heat-tolerant plants are most likely to do well in windy and dry rooftop conditions, but you needn’t stick to low-growing succulents. To a large extent, learning which plants are most successful on your roof is a trial-and-error process. Almost anything, aside from large trees that demand extensive space for rooting, can grow well in a container, but your particular site conditions will play a large part in determining which plants grow successfully there. Here are some things to keep in mind.
Birds, Bees, and Natives
Consider growing drought-tolerant species native to your region. Native plants are prime attractors for local wildlife, so even the most humble rooftop container garden can become a habitat for local pollinators and birds. Veteran roof gardener Ellen Spector Platt, who presides over a garden of more than 75 containers on the roof of her Manhattan high-rise apartment building, frequently spots butterﬂies, songbirds, and pollinating moths ﬂitting through her garden—18 stories above street level.
At the same time, Platt, who was once in charge of a ﬁve-acre farm in Pennsylvania, appreciates how the location protects her garden from unwanted predators. “Up on the roof, you never have to worry about deer nibbling your plants,” she says.
Trees and Shrubs
Many small ornamental trees and shrubs like river birch (Betula nigra), serviceberries (Amelanchier species), and Japanese maple (Acer palmatum) do quite well in rooftop gardens if they’re planted in large, stable containers and protected from the wind. This will add substantial weight, however, so be sure to determine whether or not your roof can bear it before you invest the effort and expense. After a few years you may need to do some root trimming to keep your plants to a manageable size.
Weeds and Pests
Plan on dedicating some time in the warm months to weeding and deadheading. Check your plants carefully for insect pests and diseases—early detection can help you avoid the need for chemical intervention. Beware that windy rooftops are often host to volunteer plants—mugwort, clover, or even a feral maple may try to establish themselves in your containers. Remove dead leaves and other detritus before they clog your roof’s drain.
Just as rooftops are harsher climates than ground-level gardens in spring, summer, and fall, they can be extremely bleak environments during the winter. Do some research to ﬁnd out what your plants will need for winter protection. Some smaller plants can be brought inside, and large perennials should be winterized with extra mulch. Woody vines and shrubs like American wisteria (Wisteria frutescens) and arborvitae (Thuja species), as well as containerized trees like Japanese maple (Acer palmatum), ﬂowering plum (Prunus triloba), and river birch (Betula nigra), usually overwinter well with protective wrappings of burlap or plastic.
Sunny rooftops can be great spots to grow edible plants. Many vegetables, herbs, and fruits are annuals, so you can try different varieties and cultivars each year. They’re also great plants to share with your neighbors. Roof gardener Platt cultivates a “pinch an inch” patch of lettuces and herbs and invites everyone in her building to collect from it.
One year she grew peanuts, much to the amazement and education of the city-dwelling children in her building, who had never conceived that this snack food comes from a plant. Anything you grow to eat on your rooftop should be carefully washed beforehand: Just like streetside and backyard urban gardens, urban rooftops—particularly those near major roadways—receive airborne pollution.
You don’t need a lot of space to create a container garden worthy of guests. Brooklyn roof gardener Chris Phillips keeps about 15 containers—from small pots of coleus to huge planters containing large evergreen shrubs—on a 6-by-12-foot common roof deck atop his coop building. Many of Phillips’s neighbors hold cocktail parties and cookouts in the garden, which includes a dining table and chairs, so his focus is on creating a space for evening enjoyment. To that end, he avoids edible plants and instead grows decorative ones, especially those with white ﬂowers that are visible to nighttime visitors. Phillips has also had success with fragrant plants like lavender and roses.
Roof gardens are a great way to draw people together, whether you’re the sole owner and use it for hosting guests or live in a shared building with dozens of tenants. Even a small number of plants on the roof can transform an otherwise barren space into an outdoor oasis. Add some solar lanterns, a deck chair or two, and a picnic table, and you may ﬁnd you never want to descend the stairs back to your indoor home.
This article was originally published in Green Roofs and Rooftop Gardens (2010), part of the Brooklyn Botanic Garden Guides for A Greener Planet series.
Medi Blum is the former editor of Plants & Garden News and Urban Habitats.
Rooftop Garden Guide
Get answers to common rooftop garden questions By Amber Freda
Swipe to view slides
- This 6th floor, pre-war rooftop garden had weight restrictions of 35 pounds per square foot. We designed around the weight restrictions by using lightweight potting soil and putting a false bottom inside the planters to reduce total soil volume. Photo by: Amber Freda Home & Garden Design.
- For this roof deck near Gramercy Park in Manhattan, we ran low-voltage lighting lines and drip irrigation lines underneath the deck and up into the planters before all of the screws were completely drilled into the deck planks to help make them invisible. Photo by: Amber Freda Home & Garden Design.
- This roof garden in the middle of Manhattan’s Chelsea neighborhood features lightweight aluminum decking, ipe planters, an ipe and metal pergola, and ipe benches with built-in storage under the seats. Photo by: Amber Freda Home & Garden Design.
- All of the planters on this rooftop terrace in Manhattan’s Upper East Side contain drip irrigation lines set on an automatic timer for stress-free maintenance and low-voltage up-lighting for nighttime ambiance. Photo by: Amber Freda Home & Garden Design.
- Bamboo was planted on this rooftop terrace located on Manhattan’s Upper West Side because it can tolerate conditions ranging from full sun to full shade, does really well in containers and provides instantaneous lushness against the monolithic looking black metal wall. Photo by: Amber Freda Home & Garden Design.
- For this Harlem roof deck, we kept the great views of the city skyline open with low plantings of variegated willows, Alberta spruces, and torulosa junipers. Photo by: Amber Freda Home & Garden Design.
Are you thinking of transforming your rooftop into a garden? Rooftop gardening has its own unique challenges and caveats that may surprise even the most seasoned of gardeners. Read these frequently asked questions before heading into the project.
Can I have a garden on my rooftop?
Yes, anything is possible. First, it’s important to know the difference between a roof garden and a green roof. A green roof can be done on any roof, even a slanted one. A green roof usually consists of shallow plastic or metal trays filled with sedums, grasses, or perennial wildflowers. It’s lightweight and easy to install. A roof garden usually consists of larger planters filled with a mix of evergreens, flowers, shrubs, and grasses. A roof garden might also include outdoor furnishings and can be thought of as an outdoor room. A roof garden usually exists on a mostly flat roof surface, due to the weight of the materials and the way the space is going to be used.
GET AMBER’S CHECKLIST FOR DESIGNING ROOFTOP GARDENS
The most basic requirement is that you know how many pounds per square foot your roof can hold so you can determine how much weight it will be able to withstand in terms of decking, planters, furnishings, etc. An architect, developer, or building manager may be able to tell you what the weight-bearing load is for the roof. If that information is unavailable, you may require the services of an engineer and/or a roofing contractor that can do a probe to determine this information.
How can the weight be kept down?
Pre-fabricated wood, fiberglass, and metal planters are usually pretty lightweight to begin with. Custom planters are bulkier and can be designed with false bottoms in them to help reduce the total amount of soil needed to fill them. As far as decking goes, wood or porcelain decking is usually lighter weight than stone or concrete.
What utilities are required for a rooftop garden?
An outdoor faucet is a must for a roof garden. An automated drip irrigation system can usually be installed for around $1,000-2,000, and it will be an enormous time-saver, as well as help extend the longevity and health of the plants. It usually pays for itself within the first year by greatly reducing the need for replacement plantings. An electrical outlet is useful to have if you plan to install low-voltage landscape lighting.
What are some important safety considerations for rooftop gardens?
Railing heights should conform to local laws. You will also want to check out your local laws with regards to flammable materials. NYC only allows 20% of a building’s total roof surface to be covered in wood decking. Umbrellas tend to be a safety concern. There are versions out there that are rated for wind permeability because they have extra vents built into the canopies that allow the air to pass through without lifting the entire thing up like a sail. There are also umbrellas with very heavy bases, like the Tuuci umbrellas, which are 500 pounds and in very little danger of ever being blown off a roof.
How can views, both good and bad, be handled?
We usually block unattractive views of neighboring rooftops, buildings, or walls using plantings like tall evergreens or fencing. We try to keep the more attractive views open by using lower plantings in those areas.
What types of plants are best suited for rooftops?
Gardening on top of a roof can be likened to gardening on top of a mountain. We tend to select plants that are more bottom-heavy than top-heavy to help avoid having them get blown over in high winds. Most evergreens work well for this reason, as well as multi-stem and weeping trees. We also try to avoid plants with large leaves, like elephant ears, which will tend to get easily shredded up by the wind. Finally, we recommend measuring the total number of sunlight hours the space receives per day to help determine whether you should use plants for full to part sun or mostly shade.
What features can be incorporated into a rooftop garden?
There are very specific fire code rules for every city that must be looked into for fire pits and grills. In NYC, the only ones that are allowed are electric, charcoal, or dedicated gas lines. Propane tanks are strictly forbidden. We usually incorporate a combination of high-voltage wall sconce lighting and low-voltage landscape lighting in the planters for a more ambient effect. For shade, we would probably recommend an umbrella, shade sail, awning, or pergola, depending on the aesthetic and budget of the client. Jacuzzis are usually allowed as long as they aren’t too heavy for that particular roof. The most difficult thing with a Jacuzzi is usually getting it to the roof — a crane may be required, which can be pricey.
Amber Freda is recognized across NYC for her landscape design expertise. Her company, Amber Freda Home & Garden Design, offers design and installation of roof gardens, terraces, backyards, patios, and decks.
Designing a Luxury Rooftop Terrace
by High Country Gardens
Plants for rooftop container gardens need to be tough plants that thrive in sunny, hot/cold, dry, windy conditions.
Rooftop gardening has its own set of challenges, but it’s no more difficult than traditional, in-ground gardening, it’s just different. Let’s review the growing conditions on a typical roof, and you’ll see what I mean.
Most rooftops are full sun growing situations. In cities with competing high-rises, one building may cast a shadow on a neighboring roof, but in general, rooftop gardens are full sun gardens. Growing conditions are hot and bright.
Containers can be filled with annuals or perennial plants.
As you rise above ground level, wind gets stronger; this both helps and challenges the rooftop gardener. Good air circulation reduces the chances of fungal diseases (e.g. black spot of roses, powdery mildew on bee balm). However, wind wicks moisture away from leaf surfaces, so plants with delicate foliage (ferns, Japanese maples) may become wind burned.
When you consider the things that make rooftop gardening different from in-ground gardening, it’s clear that plant choice is important. You need tough plants that thrive in sunny, hot/cold, dry, windy conditions.
Look for plants with these physical characteristics:
- Fuzzy leaves and silver foliage are adaptations that slow the evaporation of water from leaf surfaces. Consider lamb’s ears, lavenders, and sages.
- Plants with tap roots store moisture in specialized root tissue. Butterfly weeds, coneflowers, and false indigo are good examples.
- Succulent plant tissue stores moisture that plants can draw on in times of drought. Many succulents grow well in containers, like stonecrops, spurges, and yuccas.
- Evergreen trees and shrubs are often drought tolerant. Their small leaf surfaces lose water slowly, and stiff leaves with waxy surfaces have an extra layer of protection against drying winds. Junipers, Oregon grape, and arborvitae are excellent choices.
The roots of container plants are more exposed to cold temperatures than the roots of plants in an in-ground garden. They simply don’t have as much soil insulating the root zone. When planting a container garden, choose plants for one hardiness zone colder than you would for an in-ground garden. And if your container is on a rooftop, subtract one more zone to compensate for the cooler temperatures above ground level.
Ornamental Grasses can play a beautiful role in container gardens.
Rooftops are man made structures and most were not constructed with gardens in mind. If you’re going to grow a few pots of tomatoes, you’re probably fine, but if you want to plant an extensive rooftop garden, get an engineer’s report to make sure your roof is up to the task. In all my years of rooftop gardening I’ve never had this be an issue, but let’s play it safe.
Edibles can also be part of a rooftop garden.
To minimize the weight of your rooftop garden, use a lightweight potting mix rather than topsoil. Potting mixes may be either soilless or soil-based. Soil based mixes will be heavier, but will retain moisture longer. Soilless mixes are lighter weight and dry out more quickly.
Containers add to the weight on the rooftop; wood, terra cotta, and metal are heavier than plastic and fiberglass. Container material also effects your watering schedule. The potting mix in porous containers (terra cotta, wood) dries out more quickly than the mix in non-porous containers (fiberglass, metal, plastic), since water can evaporate through the walls of the container. And in areas where winter temperatures regularly dip below freezing, you’ll want your containers to be winter proof. Untreated terra cotta can crack with repeated freezing and thawing, and plastic may become brittle in cold temperatures. The most durable choices for containers that overwinter outdoors are fiberglass, metal, and wood.
I’ve saved the most important consideration for last: How do you water rooftop gardens? I have two words for you: drip irrigation. It’s the most efficient way to water plants because it delivers moisture directly to the roots of the plants. It can also be automated so your garden is watered when you’re away, and it releases you from the chore of hand watering, so you’ll have more time to relax and enjoy the garden you’ve created.
A rooftop garden is a terrific way to make the most out of unused space and bring more greenery into your life. Not to mention all the great things it does for air quality, rain capture, and building temperatures. But that’s another blog post!
Ellen Zachos is a Harvard graduate and received her certification in Commercial Horticulture and Ethnobotany from the New York Botanical Garden. As the owner of Acme Plant Stuff, Ellen designs, installs, and maintains both interior and exterior gardens in the New York City area. Ellen is an instructor at the New York Botanical Garden, where she teaches for both Continuing Education and The School of Professional Horticulture. She lectures on a wide variety of topics at flower shows, nurseries, and for horticultural organizations around the world.
Are you growing a Terrace Garden? If yes then this informational guide on ‘Terrace/Roof Garden Plants’ will surely help you in choosing the plants for terrace garden.
First, assess these characteristics of your terrace accurately: Do you want to grow plants on its floor, in raised beds or in pots? Do you have large or small terrace? Is it shady or sunny?
Selection of terrace garden plants completely depends up on the factors listed above.
In general, better to choose large containers when growing plants for terrace garden because in large containers, plants grow more easily: better moisture conservation and nutrient supply, room for ample root development.
Terrace Garden Vegetables
Well sized pots or raised beds, an ideal exposure to sun, water, slightly acidic and fertile soil and sufficient drainage, this is all you need to have your own vegetable garden.
Vegetables need more care then herbs, so if you’re growing them for first time, start by salads: tomatoes, especially cherry tomatoes, radishes and cucumbers are easy to grow.
You can also grow vegetables such as eggplant, peppers, okras (lady finger) and chilies and strawberries (fruit of course). If you’ll dedicate at least half an hour in a day to some regular gardening chores like pinching, pruning, watering and fertilizing every couple of week or in a month according to your plants’ needs, you’ll get success.
Terrace Garden Flowers
If you feel an urge to grow different, exotic and beautiful flowers on your terrace to make a roof flower garden then grow lot of annuals.
You can plant some tulip bulbs and hyacinths, colorful primroses are also easy to grow.
In summer, grow petunias, pansies and begonias and some exotic flowers depending on your climate.
Hibiscus comes in variety of colors, grow it, you can plant roses, too.
If you live in warm climate, grow these flowers in fall and winter.
Also Read: Rooftop Garden Design Ideas and Tips
The first way to get into the gardener’s skin is often begins with a pot of basil that arises near the edge of the kitchen window.
Gradually, try various herbs to enhance taste of your dishes and salads. Herbs are quickest and easy to grow plants.
Thyme, rosemary, lavender and sage require less watering and grows well on a sunny terrace. Basil, chive, parsley or cilantro need moderate sun and watering. Do not forget the lemon grass and mint which can be used in many cuisines and in preparation of teas.
Depending on your climate and needs, you can try other herbs too on your terrace garden.
Also Read: How to Grow Curry Tree
Low Maintenance Succulents and Perennials
There are a multitude of succulents and perennials, that push themselves to one year to another.
In full sun to partial shade, most of the succulents are grown on well drained and dried growing medium, so they require little maintenance.
Aloes and various cacti are low maintenance. You can grow them in small pots too.
Certain grasses, sage and plants of the composite family like asters, daisies, zinnia, black eyed susan or chamomile and marigolds are possible.
If you have a shady terrace facing north, look for varieties of ferns, and other shade loving plants like English ivy, impatiens and balsams.
If the size of your terrace garden allows, make the choice of small trees, evergreen shrubs and vines.
In less sunny spot, grow camellias and rhododendrons, Japanese maples and honeysuckles, sweet autumn clematis.
In full sun, grow the lemon tree, the oleanders, olive tree, a flowering virbunum, some dwarf fruits trees like apple, pomegranates, guavas, figs and even mangoes in pot (if your climate allows).
Don’t forget to care about the water requirements, humidity levels and sensitivity of each plant and the rapid development of some vigorous plants, whose exuberance lead you to their too severe pruning or disposal.
Pay attention to the choice of containers
Pots or trays should be chosen in harmony with each plant: combining the beauty and requirements both.
Traditional Terracotta pots are timeless, they retain their charm in all seasons, but it must be remembered that these pots are expensive, heavier and frost susceptible.
If you do a little research and visit your nearby garden centers, you’ll find many frugal and possibilities: containers made of wood, metal, concrete and polyester resins, some flashy colored pots for darker areas.
Do not forget to partially renew the potting soil annually or periodically by adding compost and manure. You’ll also need to repot some large plants once in a couple of year for their development and growth.
Also Read: Roof Garden Designs
The best roof garden plants are low maintenance and able to survive the harsh conditions present on rooftops. Urban rooftop gardens make exquisite spaces that can be surprisingly low maintenance, if you use a good mix of the best roof garden plants.
Rooftop Garden Plants Must Withstand These 2 Things
High Heat Exposure
Roof gardens are exposed to a lot of heat on a regular basis. That means plants must be tolerant of high heat and sun.
High Wind Exposure
The taller a building is in relation to its surrounding buildings; the more susceptible roof top gardens are to high winds.
They have tap roots
Plants with tap roots are defined by the fact they can store moisture in specialized root tissues. Examples of tap root plants include Butterfly Weeds, False Indigo, and Coneflowers.
They have furry leaves
Plants with fuzzy leaves and silver foliage tend to show slower evaporation of water from leaves. This helps them withstand a lot of heat and direct sunlight without drying out as quickly. Good examples of furry leaf plants for rooftops include sage and lavender flowers.
They are part of the succulent plant family
Succulent plants are hardy as heck! They store excess moisture in their leaves, which allows them to survive harsh dry conditions—hence why they are a popular desert plant. Some examples of succulent plants that grow well in containers include yuccas and stonecrops.
The Importance of Hardiness Zones for Rooftop Gardens
Rooftop plants are exposed to harsher conditions than plants on the ground. It’s not just the sun. Container plants are more susceptible to chill in the winter compared to in-ground plants because they don’t have as much soil protecting their roots. As a result, look for plants that are approved for at least one to two hardness zones colder than your region.
What About Rooftop Garden Trees?
Evergreen trees and shrubs are commonly used to outfit rooftop gardens because of their hardy and drought-resistant properties. Thanks to compact leaf surfaces, these trees and shrubs lose water slowly. Plus, the waxy residue on foliage offers an extra barrier against high winds that can otherwise dry out plants. Some great evergreen trees include Oregon grape, junipers, and arborvitae.
The Kousa Dogwood tree is hardy to Zone 5 and is considered a small tree but can grow as large as 30-feet. The tree contains a variety of small white and pink flowers, which turn a vibrant green in the summer. During fall, the tree sprouts with red-purple leaves and fruit.
Harry Luader’s Walking Stick adds dimension to any space thanks to its twisty roots. The tree/shrub produces a round, heart-shaped foliage. It can grow as tall as 10 feet. Hardy in Zones 4-8. Keep in mind, this plant is considered invasive in some areas.
Diverse Plants for Rooftop Gardens
Some portions of your rooftop garden might be shadier than others. If you have a great shady spot you might want to consider planting Big Daddy Hosta. The leaves on this plant are impressive due to their bright blue-green coloring and monstrous size. Hardy in Zones 3-8, this is a great filler plant for shaded portions of your rooftop garden.
What about rooftop vines? Climbing hydrangea is an excellent option if you want to add vines to your rooftop garden. This type of self-adhering plant vine blooms with delicate white flowers and can reach up to 60-feet in length. Approved for hardy Zones 4-8; this is a low maintenance plant that offers beautiful color in autumn and spring.
How to Water Rooftop Plants
A drip irrigation system is a great way to manage rooftop gardens. You may also want to consider investing in self-watering planters. This will help prevent plants from soaking up too much water—in the instance there’s a storm or someone overwaters them. It also prevents root rot because water builds up in a chamber underneath roots, as opposed to in the soil with the roots.
Self-watering planters are beneficial in the summer too, as they can help prevent plants from drying out. The water collection chamber can be accessed when the roots extend down.
What Type of Planters Should You Use for Rooftop Gardens?
If it gets cold in the winter, you need solid winter-proof planters. Many planters are not made to withstand freezing cold temperatures and will crack as a result. For hot summers, the right materials matter to help prevent plants from drying out quickly. Additionally, you don’t want to get too much weight on a roof, and that’s where lightweight planters come in handy. Plus, lightweight planters are easier to transport on top of your roof in the first place.
Our planters are made to withstand the harsh conditions experienced on rooftops—from heat, to cold, and everything in between. No one makes a more durable planter than us. Plus, they are made right here in the USA!
Shop our huge selection of commercial and residential planters here: https://www.terracastproducts.com/our-shop/planters/