When to plant melons?

Quick Guide to Growing Cantaloupe and Honeydew Melons

  • Plant cantaloupe in an area with warm soil (70°F+) and plenty of sun.
  • Cantaloupes are sprawlers, so plant them 36 to 42 inches apart in fertile, well-drained soil.
  • Growing cantaloupes require a lot of nutrients, so it’s best to improve your soil by mixing in several inches of compost or other rich organic matter.
  • Cantaloupes need a lot of water, so keep soil moist and avoid wetting the leaves—soaker hoses and drip irrigation are best.
  • Mulch well and eliminate weeds early so vines can run freely.
  • Protect young fruits by getting them off the ground. A small upside-down flower pot will work well.
  • Avoid pinching off shoots because an abundance of healthy leaves will produce sweeter fruit.
  • For best flavor, leave the largest fruit growing on the vine and pinch off any young fruits that begin to form.
  • Harvest cantaloupe when they reach ideal color and the netting is pronounced.

Soil, Planting, and Care

Cantaloupe and honeydew melons thrive in warm soil. Don’t plant until the ground temperature is above 70 degrees F, which typically occurs about the time peonies bloom in northern zones. Prior to planting, cover soil with plastic film to hasten soil warming. Because cantaloupes and honeydew are heavy feeders, prepare your planting bed well. The quick way is to plant in soil amended with several inches of compost or well-rotted manure, if available, or with aged compost-enriched Miracle-Gro® Performance Organics™ All Purpose In-Ground Soil. Then feed regularly through the growing season with Miracle-Gro® Performance Organics™ All Purpose Plant Nutrition Granules, which nourishes both plants and the beneficial microbes in the soil (be sure to follow label directions). This combination of nutrient-rich soil and premium plant food is an excellent way to ensure a great harvest!

There is another way to plant–a technique used by the hard-core. Excavate the soil 1 foot deep, add a 9-inch layer of fresh manure, and then cover that with 3 inches of soil mixed with compost. This creates a bed with a high-nitrogen soil base that is naturally warm because it generates a little heat as the manure composts. In yet another approach, some gardeners plant melons atop their compost piles to ensure a warm footing and adequate nitrogen.

Melons need room to roam. Space plants 36 to 42 inches apart. Or, to save space, plant melons 12 inches apart at the base of a trellis. When trellising melons, tie vines to the trellis daily, using soft plant ties that won’t crush stems. A trellis for cantaloupe should be large: up to 8 feet tall and 20 feet wide in warmest climates. Wire fencing works well. Trellising offers several advantages: Vines get better air circulation than on the ground, which reduces the chances of disease. In northern zones, vines also get more sunlight when on a trellis that’s positioned at a slant toward the sun. You can also place a trellis against a bright reflective surface, which increases the amount of light reaching leaves and confuses melon aphids, who like to hide on the shadowy undersides of leaves. If you use a trellis, anchor it firmly so gusty summer winds don’t topple the vine-covered trellis.

After planting in spring you can cover plants with floating row covers to exclude insects and trap warm air near plants; this is most important in cooler climates but is useful everywhere to keep certain pests off the plants. In cool climates you can also lay out a permeable black tarp or black landscape fabric over the area to help trap the sun’s warmth. Simply plant through it (cut x-shaped slits).

Vines bear male and female flowers. Male flowers open first, joined by female blossoms about a week later. Female flowers have a small swelling at the base of the flower. When vines start to bear male and female flowers, remove row covers so bees can visit the flowers.

Tackle weeds before vines start to run, because later it will be impossible to step among vines without crushing them. Mulching soil under vines suppresses weeds and slows moisture evaporation from the soil. Of course, if you planted in a black cover, that is already done.

Water may be the most important variable that you supply; melons need a steady supply. Vines are most sensitive to drought during the time between transplanting and when fruits start to form. Keep soil consistently moist but not waterlogged, which will kill plants. It’s typical for leaves to wilt under midday sun, but they shouldn’t remain wilted into the evening. If possible, avoid overhead watering. Soaker hoses and drip irrigation deliver water directly to the soil, preventing possible spread of fungus diseases on wet foliage. If you must use a sprinkler, then water vines very early in the morning so that leaves can dry early, which helps prevent fungus diseases.

For vines running on the ground, keep fruit from direct contact with soil to prevent rot and protect fruit from pests. Place ripening fruit on mulch, upturned coffee cans, or flower pots. If large critters such as groundhogs discover your melons, protect ripening fruits by covering them with plastic milk crates or similar boxes weighted down with a few bricks.

An old garden adage suggests pinching off a vine’s growing shoots as melons start to ripen to cause the plant to divert all its energy to the ripening fruit. Research has proven this false. The vine needs all its leaves to produce the sugars that sweeten fruit. Anything that reduces the total number of leaves available for sugar production reduces melon sweetness.

The more fruits that ripen at the same time, the less sweet they’ll be, since the vine will have to divide the leaves’ sugar production between fruits. In warmer climates with a long growing season, experienced growers often prune off all but one newly forming melon every 2 weeks. Ripening 1 melon at a time yields maximum sweetness. As you gain experience, you’ll develop your own technique.

In colder regions, remove any blossoms that start to develop within 50 days of your area’s first average frost date. This ensures remaining, larger fruits will ripen before frost.

8 Tips for Growing The Sweetest Melons

Sweetness is graded on the Brix scale, which measures the percentage of solids (everything that’s not water) in juice extracted from fruit. Those solids include not just sugars, but amino acids, proteins, minerals and vitamins – in other words, fruit that is sweeter also has more complex flavors and a better nutrient profile.

Hot Tip: Sweeter fruit has a better nutrient profile.

The Brix rating, often abbreviated ‘Bx’, results from the interplay of genetics, climatic conditions, soil conditions, and ripeness. Below are a few considerations for how to harness those forces in the name of producing the sweetest possible melons.

Start with the Sweetest Varieties

All else being equal, some melons are naturally sweeter than others purely on the basis of genetic composition. Some seed purveyors list the average Brix rating for their melon, but for many common varieties that information is easily obtained through a quick internet search. A Brix rating of 12 is considered pleasantly sweet; 14 is very sweet; and 16 is over-the-moon sweet.

Sow Seeds Early

A long, hot growing season is required for optimal ripeness, and thus sweetness. Start melon seeds indoors in 4-inch pots at least six weeks before the average date of last frost in your area so that the seedlings are already well-established once warm weather hits. If you transplant the seedlings outdoors when the weather is cool, they’ll stop growing; so wait a couple weeks after the average date of last frost to do so, or until nighttime temperatures are consistently above 60 degrees.

Find Your Warmest Microclimate

Heat brings out melons’ sweetness, so make sure to plant them in a location that warms up early in spring and stays hot through the end of September. The south side of a fence or wall is ideal as the structure will absorb heat and light from the sun and reflect it back onto the melons. Locating the melons near a sunny brick patio or other paved surface also helps to create hot microclimate for these tropical plants. Such measures aren’t necessary in southern California, the desert Southwest, and the Deep South, but in cooler climates melons need all the help they can get to reach optimal ripeness.

Accentuate the Sun’s Rays

You can’t do anything to change the climate where you live or the amount of sun your yard gets, but there are a couple tricks for making the most of the available heat in any location. Covering the soil in melon beds with garden-grade black plastic film, which traps heat much like an asphalt surface, is one time-honored trick. You can also install clear plastic or see-through fabric “row covers” over melon beds to create a mini-greenhouse. These must come off in early summer when the plants begin to blossom so that insects can pollinate the flowers. Cover the beds again in late summer to ensure optimal ripening as the weather cools.

Don’t Crowd Your Melons

Melons grow on sprawling vines and do not ripen effectively when grown in cramped quarters. The seedlings are typically planted on mounds (three to a mound) spaced 2 feet apart in rows 6 feet apart. Thin the fruit to three melons per vine, as this will result in more nutrients (and thus sugars) pumped into each melon. If space is an issue, build a sturdy trellis and train the melons up the south side of it – this saves bed space, but also puts the fruit into better contact with the sun’s warming rays.

Sweetness Starts in the Soil

Sugars are produced in the leaves through the process of photosynthesis, and then pumped into the fruit – so the more lush the leafy growth, the higher the Brix rating. To encourage strong growth, blend 4 to 6 inches of composted manure into your melon beds prior to planting. Then add a balanced organic fertilizer (such as a mixed blood meal/bone meal product) every 3 to 4 weeks. Some gardeners elect to plant melons right into their compost pile, which not only provides loads of nutrients, but a bit of extra heat.

Water Heavily – But not During Ripening

Keeping melon leaves lush also requires copious amounts of irrigation. This is best applied with soaker hoses or a drip system, as overhead irrigation encourages fungal disease, which definitely detracts from melons’ sweetness. During the final weeks of ripening, however, excess water dilutes the sugar content of the fruit. So as the fruit approaches its full size, cut back on irrigation, providing only enough water to keep the leaves from completely wilting. It is normal at this stage for some of the older leaves to turn brown.

Pick at the Pinnacle of Ripeness

Even if you do everything else right, no melon is sweet if picked immature. Signs of ripeness include a fruity aroma, a slight softening of the rind, and a hollow sound when you strike the fruit with your knuckle. But the sure sign is how easily the fruit detaches from the vine. If it releases with a slight tug, it’s ripe enough to harvest. However, the highest sugar content is achieved when fruit detaches from the vine on its own (or if this does not occur, when the vine becomes shriveled and dry where it is attached to the melon). The risk at this stage, of course, is that birds and other critters may start eating the fruit before you do.

Growing Watermelons (Citrullus Lanatus)

How To Grow Watermelons From Seed

Growing watermelons requires lots of space, lots of sun, lots of water and lots of nutrients.

They are greedy, rambling vines, like all plants in the Cucurbita family (e.g. zucchini, squash, pumpkin, cucumbers…)

Watermelons are not particularly difficult to grow but because they are so demanding I don’t consider watermelons a good plant for beginner gardeners. (You can get lucky if you live in the perfect climate with perfect soil.)

I also don’t consider them a good plant for anyone with restricted space, water, or average soils.

You need to put a lot into a watermelon and what you get out in terms of nutrition is little… So from a permaculture point of view watermelons would not be the very first thing to worry about.

But I get too many questions about growing watermelons. They are very popular. So I give in…

How To Grow Watermelons

Where And When Can You Grow Watermelons?

In the true tropics the dry season is the best watermelon growing season.

Watermelons do not cope well with extreme heat or with the humid, soggy conditions of our wet season/summer. Fungal diseases and bugs will wipe them out in no time.

If you live in a cooler climate, then summer is the time to grow watermelons.

You need at least three months of reliably hot, sunny weather to grow and ripen a watermelon. During that time your average daily maximum temperature should be at least about 20-25°C or 70-80°F. Warmer is even better.

There are different watermelon varieties, so if you are at the low end of that, look for a faster maturing variety.

Grow watermelons in full sun. You also need an abundant supply of water and nutrients (very rich soil).

And you need space. As I said, a rambling vine. They like to go wandering and smother everything around them.

Growing Watermelons From Seed

Watermelons are grown from seed. You may be tempted to use seed out of a melon you bought, but don’t waste your time. It is almost guaranteed to be a hybrid.

Hybrid varieties are very special crosses that don’t grow true to type. You would end up growing what we call pig melons: A melon variety that’s only good for feeding to the pigs.

Buy your seed, and if possible buy an open pollinated heirloom variety. Because then you CAN use your own seed next year. The open pollinated varieties are also hardier.

You will find many more interesting varieties amongst the heirlooms than you can find in the standard collection of hybrids at your local gardening centre.

Start your watermelon seeds in the ground, right where they are supposed to grow. The soil should be at least 18°C/65F for them to germinate.

Unless you have an extremely short growing season, do NOT start your watermelon seed in a pot or punnet. Do NOT buy watermelon seedlings from a nursery.

Watermelon seed germinates easily and quickly, within a few days. Watermelon plants outgrow the seedling stage very quickly and they don’t like transplanting. You don’t save much time and you end up with a weaker plant.

Save yourself this totally needless extra work and stick your seeds in the ground, about two centimetres or an inch deep.

If you have a long growing season, you may want to do several plantings, a few weeks apart.

Watermelons need deep, rich, friable soils. To grow watermelons it helps to raise the soil (make mounds or ridges). Raising the soil has several advantages:

A mound or ridge is free draining (melons don’t like wet feet). If you have heavy clay soil, definitely raise the bed.

Mounds are also good if the soil is as poor as mine. I just make a mound of good soil with lots of compost in it to grow watermelons. Sometimes I plant them in what’s left over from a compost pile after I used most of the compost.

If you like growing things in neat rows, or if you want to plant a large area, grow watermelons on ridges, like the commercial growers do.

Rows should be about 2 m/6 ft apart and the plants spaced at 30 cm/a foot apart.

Sow twice as many as you want and keep the stronger seedlings. Just snip off the weaker one.

I prefer growing watermelons in clumps on a mound, in several different locations in the garden. Mixing things up helps keeping pests and diseases at bay. If you want several hills together, keep them about 2 m/6 ft apart.

A mound should be about one metre/three feet square and a foot high. I plant about ten seeds in it, in three groups of three to four seeds each. The groups are spaced about a foot apart (30 cm).

After a few weeks I can see which watermelon plants grow the strongest, and I snip off the weaker ones, leaving only one seedling in each group. Don’t pull them up, cut them off. Or you disturb the roots of the others.

If you have a very small garden but absolutely have to have watermelons, you can try growing them on a trellis. Really.

You need a very strong trellis, you need to train them up the trellis because they aren’t climbers so won’t climb up on their own, and you need to support the developing fruit so the trellis holds the weight, not the plant.

It is a lot of work but it can be done…

Growing Watermelon Plants

Slugs and other seedling chomping critters like mulch and they like watermelons. So wait until the watermelons have outgrown the most vulnerable stage where a slug can demolish them within minutes. Then mulch the area well.

Watermelons have very shallow roots and they need lots of moisture. The soil should never dry out and mulch helps with that.

Mulch also keeps weeds down. Weeding could disturb the shallow roots, so it’s better to not let weeds grow to start with.

Watermelons are VERY hungry plants. If your mulch is something like compost or aged animal manures, all the better. Like all cucurbits, watermelons can handle fairly raw compost and manures.

Otherwise, feed your watermelons regularly with something like pelleted chicken manure or another organic fertiliser. Ideally you should use a high nitrogen fertiliser in the early stages, but cut back on nitrogen and give them lots of potassium once they flower and fruit.

When the vines are about two metres/six feet long, pinch out the tips. It encourages branching.

As your watermelon vines grow bigger they will start trying to take over more space. If they start to smother other things you can remind them about sticking to their area by gently moving the tips of the vines, so they grow into the right direction.

Watermelon Flowering and Fruiting

Watermelons grow male and female flowers on the same vine.

The smaller male flowers appear first. The female flowers are larger and you can already see the tiny melon beginning to form at the base of the flower.

Female watermelon flower. Photo: [email protected]

If you don’t see female flowers it could have several reasons: too hot, too cold, not enough water, not enough nutrients… In any way, it means the watermelon plant isn’t happy.

If the plant does produce female flowers but the little fruit at the base of it shrivels up and dies, then the flowers are not getting pollinated.

Watermelon flowers are insect pollinated. If you suspect the insects aren’t doing their job, you can do it yourself, just to be sure.

Hand pollination is best done early in the morning. Pull off several male flowers and remove the flower petals. Then brush the pollen laden stamen against the stigma in the centre of the female flower, so the pollen sticks to it. Easy.

The first few female flowers on each branch will give you the best fruit.

To grow them as large as possible you can pinch out the tip of the branch after several fruits have set (i.e. are starting to swell up).

But this isn’t an essential step. You can also just let them go.

Harvesting Watermelons

Telling when a watermelon is ripe is an art. You will get better at it with practice.

The first sign to look for is the curly tendril at the stem. Once it is dry, as in, totally dry not just starting to dry off, once it is totally dry, your watermelon may be ready. Maybe.

Here the stem and vine is dry, too, already. Can you see the curly tendril though?

Another sign is the light coloured patch on the bottom of the fruit. It is initially greenish, but as the melon ripens the green tinge disappears and it becomes yellowish. The skin overall becomes duller and tougher.

But the most popular way to tell if watermelons are ripe is the sound. Knock them with your knuckles and listen for a dull, hollow sound. The unripe melons have a higher pitched sound. Keep thumping lots of them and comparing until you can tell the difference. Eventually you’ll have to take a chance on one…

The only way to get good at this is to grow and harvest lots of watermelons!

Problems When Growing Watermelons

The biggest watermelon pests are the leaf eating beetles (they damage the flowers, too) like spotted and striped cucumber beetles, pumpkin beetles with or without dots, whatever you want to call them.

Those orange things…

Pumpkin beetle. Photo: Doug Beckers

They all look similar and all do the same: they chomp away on your watermelon plants.

However, if they become a real problem it is mainly a sign that your watermelons are stressed.

A healthy watermelon in a balanced environment and in good soil should not attract too many beetles. Also, a watermelon should grow fast enough to cope with a few beetles.

In other words, you should spend more time worrying about providing your plants with enough enough sun, water and the right nutrients than you should spend worrying about the beetles.

The other main problem with growing watermelons is mildew, a fungus that makes the leaves look as if they were coated with white powder. The fungus thrives in damp, humid conditions.

The best you can do to avoid mildew is to avoid getting the leaves wet. If you can’t avoid overhead watering, do it first thing in the morning so the leaves dry quickly. Never wet the leaves in the afternoon or evening.

In the tropics, once the build up for the wet season starts, you probably won’t be able to control the beetles or the mildew. And it isn’t worth it anyway… The oppressive heat and the humidity just aren’t good conditions for growing watermelons. Grow something else that likes humidity and wait for the next dry season to grow watermelons again.

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All About Watermelons

Shop Watermelon Seeds

Can I Grow Watermelons?

Every gardener should plant a hill or two of watermelons as they are easy to grow and, oh so good on sultry summer afternoons.

Try a small variety such as an eight-pound ‘Seedless Big Tast Hybrid’ that will fit in the refrigerator easily, or go for the glory and sow watermelon seeds for a whopper like the 30-pound ‘Million Bucks Hybrid’. Heirloom fans will want to plant ‘Moon and Stars’, introduced in 1926 with a deep green skin speckled with tiny yellow stars and quarter-size moons. The leaves are speckled with yellow stars as well. If you don’t have room in the garden for watermelon vines, think about growing them in the middle of the lawn. Yes, in the middle of the lawn. Simply dump two 40-pound bags of composted cow manure and one 40-pound bag of topsoil into a heap on the lawn. Mix and mound with a trowel or by hand to integrate all materials. Water well and plant 6 to 8 seeds and later thin to three plants. The vines will ramble all over the lawn, and you will have to mow around them. But, the watermelon foliage will shade most of the grass underneath it and slow growth.

After harvest, pull up watermelon vines; rake the nutrient-rich manure mix over the lawn for fertilizer and water well. Within a week, the grass will be growing vigorously again, and it will be a healthy dark green.

Watermelon Plant History

Watermelons probably originated almost 5,000 years ago in the Kalahari Desert of Africa where botanists have found its wild ancestors still growing. Watermelons migrated north through Egypt, and during the Roman era they were cultivated and prized. Hieroglyphics on the walls of Egyptian buildings tell stories of their harvest. Watermelons were buried in the tombs of kings to nourish them in the afterlife. Melons spread across the European continent and particularly flourished in the warmer Mediterranean areas. Watermelons were documented in 1629 in Massachusetts. During the Civil War, the Confederate Army boiled watermelon to make molasses for cooking. It is in the Southern states such as the Carolinas and Georgia where watermelons flourish as commercial crops. Numerous varieties were developed, and variations of flesh color surfaced. By the late 1800s, the W. Atlee Burpee & Co. was developing its own watermelon varieties and selling seeds.

Should I Grow Watermelon Seeds Or Plants?

Watermelons need a long growing season (at least 80 days) and warm ground for seeds to germinate and grow. Soil should be 70 degrees F or warmer at planting time. Sow seeds 1 inch deep and keep well watered until germination. To get a jumpstart in cooler climates, cover the planting area with black plastic to warm up the soil and start seeds indoors two or three weeks before they are to be set out in the garden. Don’t start seeds any earlier, because large watermelon seedlings transplant poorly. Plant 3 seeds in 3- or 4-inch peat pots or large cell packs, and thin to the best plant. Sow watermelon seeds 1/2 inch deep. Place in a sunny south-facing window or under lights to germinate. Make sure the area is warm?day and night?ideally 80 degrees F. Use a Seedling Heat Mat if necessary.

How To Cultivate Watermelon Plants

Watermelon is a space hog; vines can reach 20 feet in length. So plant where there is plenty of open ground. Amend soil with organic matter such as compost or composted cow manure. Add a balanced fertilizer that is high in nitrogen. Sow 8 to 10 watermelon seeds in a hill, and push seeds 1 inch into the soil. Space hills 3 to 4 feet apart, with at least 8 feet between rows. Thin plants to the 3 best in each hill. Keep soil free of weeds by shallow hoeing or with a layer of mulch.

Watermelon Plant Growing Tips

Watermelon Plant Insects & Diseases

Watermelon Harvesting Tips

Knowing how to determine when a watermelon is perfectly ripe is not easy. One way favored by many gardeners is to watch the tendril closest to the melon stem. A tendril is a modified leaf or stem in the shape of slender, spirally coil. When it turns brown and dries up, the melon is ripe. The trouble with this method is that with some watermelon varieties, the tendril dries and drops off more than a week before the melon is fully ripe. Slapping and tapping or thumping are other common methods used to determine ripeness, but they are not always accurate.

The surest sign of ripeness in most watermelon varieties is the color of the bottom spot where the melon sits on the ground. As the watermelon matures, the spot turns from almost white to a rich yellow. Also, all watermelons lose the powdery or slick appearance on the top and take on a dull look when fully ripe. After picking a watermelon, chill it before serving for best flavor. Some folks sprinkle a little salt on their watermelon, but it’s probably thought of as a cure for poor tasting store-bought melons and certainly not necessary for home-grown. If the seeds present a problem, grow seedless watermelon varieties like ‘Seedless Sugar Baby Hybrid’ or ‘Orange Sunshine Hybrid’. A cut melon, if covered with plastic wrap or aluminum foil, will keep several days in the refrigerator.
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