When to fertilize seedlings?


How and when to begin to fertilize seedlings

I started some broccoli, Brussels sprouts and parsley seeds under a set of grow lights a few weeks ago. I also plan to start some tomatoes and peppers soon. I’d like to know how and when to start fertilizing them. Right now the early crops are about an inch and a half tall. Everything looks good, but I want to make sure they’re healthy when I move them out to the garden.

Seed starting is a favorite hobby of many gardeners. It allows us to grow many more varieties than we can get at a nursery, plus it’s cost effective and fun. Using a lighting system is a smart way to keep the plants growing straight and strong.

If you used a potting soil formulated specifically for seed starting (as you should), there’s typically a small amount of fertilizer included in it to help your seedlings get off to a good start. There isn’t a lot of fertilizer added, however, since too much can burn young seedlings and their roots. As your plants grow, they quickly use up any fertilizer found in the seed-starting mix, and you’ll need to start feeding them a supplemental fertilizer.

Fertilization should begin soon after your seedlings form their first “true” leaves. The initial leaves that emerge from a seed are called the cotyledons. They’re rounded with smooth margins. The second set of leaves to emerge are the “true” leaves. They look very similar to the foliage of the mature plant. When the first set of “true” leaves has fully emerged, it’s time to move your seedlings to the next stage in their care.

First, when the “true” leaves arrive, it’s your signal to transplant the seedlings into larger containers or cell packs, using a standard potting mix that already contains a nutrient source. There are lots of different potting mixes out there you can use, but I prefer ones that contain naturally derived nutrients, rather than brands containing a chemical fertilizer.

Next, about two or three weeks after transplanting, it’s time to begin to fertilize the seedlings with a liquid organic fertilizer. Dilute the fertilizer to half the strength recommended on the bottle, and use it every two to three weeks. Choose a product formulated for use on seedlings (I use Espoma’s Grow), liquid kelp or fish emulsion.

Your strong, healthy seedlings will have to be hardened off before planting them out into the garden. This is an important step in the process to avoid burning the plants in the hot sun or freezing their tender foliage during cold nights.

For two weeks prior to moving the plants out into the garden, work on slowly acclimating the seedlings to outdoor conditions. Begin by placing them in a shady spot outdoors for just a few hours. Gradually leave them outside for longer periods of time and expose them to more sunlight until they are outside full-time. This hardening off process is extremely important to those young transplants and helps them gradually adjust to brighter light levels, wind and fluctuating outdoor temperatures.

  • Horticulturist Jessica Walliser is the author of several gardening books, including “Attracting Beneficial Bugs to Your Garden,” “Good Bug, Bad Bug,” and her newest title, “Container Gardening Complete.” Her website is jessicawalliser.com. Send your gardening or landscaping questions to or The Good Earth, 622 Cabin Hill Drive, Greensburg, PA 15601.

    Categories: Lifestyles | Jessica Walliser Columns

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    Fertilizing Bedding Plant Seedlings

    Fertility is an important factor in the production of high quality seedlings by the plug method or traditional row or broadcast methods. Recent research has shown that fertilization must begin shortly after germination and that abnormal seedling growth is often caused by nutrient disorders.

    The success of a fertilizer program for bedding plant seedlings and transplants is determined by more than just the rate (ppm) of fertilizer applied. Other factors which are as important as rate include fertilizer type (NPK analysis, micronutrient package, proportion of ammonium (NH4) vs. nitrate (NO3), and pH effect), frequency of application, volume of fertilizer solution applied, and how much leaches from the container. Also the growth rate of the young plant as it is affected by light intensity and temperature influences the fertility requirement of the plants.

    Fertilizing Seedlings and Plugs

    Plug researchers have identified four stages of seedling growth and have developed guidelines for fertilizing each stage (Table 1). Fertility is not a critical factor for most species during Stage 1 because most seeds have enough stored nutrients to carry out germination. Also, many germination media have a starter charge of fertilizer which is effective at supplying nutrients as the root emerges and elongates. The most important factors for germination are temperature of the growth medium and a proper balance between moisture level and aeration. Beginning in Stage 2 a dilute fertilizer program is normally started and the rate of application is gradually increased as the seedlings grow larger and approach transplanting. The rates in Table 1 are general starting points and they can be fine-tuned by the individual grower

    Table 1. Fertilizing seedlings before transplanting.
    Seedling or plug stage of development Water-soluble fertilizer program
    Stage 1: Germination and root emergence. No fertilizer
    Stage 2: Opening of the cotyledons. 25-50 ppm N
    Stage 3: Development of 1st set of true leaves. 50-100 ppm N
    Stage 4: 1st set of true leaves to transplant. >100 ppm N

    Seedling Disorders Related to Fertility

    During Stages 2 and 3 several nutrient disorders may occur, they are: 1) shoot tip distortion or death, 2) misshapen cotyledons or true leaves, or 3) seedling chlorosis. Shoot tip and young leaf abnormalities have been linked to excess soluble salts and deficiencies of either calcium (Ca) or boron (B). Seedling chlorosis may indicate low overall nutrition or a deficiency of iron (Fe). It is important to remember that non­nutritional problems may cause similar symptoms. For example, temperatures below 65°F or chronic, prolonged periods (>4 hr) of water droplets standing on the growing points may cause shoot tip and young leaf abnormalities.

    Fertilizer Program Affects Seedling Size

    In Stages 3 and 4 the fertility program can have significant effects on seedling height and overall size. Levels of overall nutrition, NH4 vs. NO3 nutrition, and phosphorus (P) nutrition have the greatest effects on size.

    Traditionally, many growers have slowed the growth of bedding plants by not fertilizing or using very low levels. This approach is very effective at reducing height and may improve root growth. However, the disadvantages of low nutrition are that the seedlings become chlorotic and may fall behind schedule. On the other hand high nutrition will prevent chlorosis and keep the plants on schedule, but the seedlings may become too large and the root systems may be small. A moderate level of nutrition (100-150 ppm N) is probably the best compromise.

    Research has shown that seedlings and young plants of many bedding plant species grow taller and are greener with NH4 compared to N03 nutrition. Taller plants result from using fertilizers supplying >50% NH4 (e.g., 15-15-15, 15-16-17, 20-10-20) and shorter plants can be had by fertilizing with a high NO3 fertilizer (e.g., 15-0-15, calcium and potassium nitrate, EXCEL fertilizers). These effects are somewhat complicated by the pH effects and the P levels of the fertilizers.

    A mild deficiency of P can reduce height without causing nutrient deficiency symptoms or delay in plant development. The method has been used most successfully with petunias and tomatoes, but most bedding plants are probably responsive. Fertilizers to try are those with a P analysis is 0-2%. Very little P is required to satisfy the requirements of common bedding plants. In fact, the starter charge in many soilless media seems to be enough to carry marigolds and seed geraniums to flowering with little or no effect on height.

    pH Requirements of Seedlings and Plugs

    Growth medium pH is an important factor in seedling production. pH-related problems are common for plugs because of the very small volumes and limited pH buffering capacity of growth medium in plug trays. Many bedding plant species are tolerant of a wide range of pH levels. However, researchers at North Carolina State University have found that a number of bedding plants have very specific requirements (Table 2). These specific pH ranges are needed to prevent micronutrient toxicities or deficiencies of B, Ca, and Fe.

    Table 2. pH ranges for bedding plant seedlings.


    pH Why?
    Most bedding plants 5.4-6.8 pH tolerant
    Celosia 6.0-6.8 Prevent Fe/Mn toxicity
    Dianthus 6.0-6.8 Prevent Ca deficiency and NH4 toxicity
    American marigolds 6.0-6.8 Prevent Fe/Mn toxicity
    Geranium 6.0-6.8 Prevent Fe/Mn toxicity
    Pansy 5.4-5.8 Prevent B & Fe deficiency
    Petunia 5.4-5.8 Prevent B & Fe deficiency
    Salvia 5.4-5.8 Prevent B deficiency
    Snapdragon 5.4-5.8 Prevent B & Fe deficiency
    Vinca 5.4-5.8 Prevent B & Fe deficiency
    North Carolina State University Plug Research Group

    Several factors interact to determine pH of a growth medium: materials used to formulate the mix and the amount of limestone added, irrigation water alkalinity, use of acidic or basic fertilizer, and plant species. Most soilless growth media are very acidic to begin with and a portion of the acidity must be neutralized with limestone in order for the starting pH to fall in the range of 5.4 to 6.8.

    The remaining factors come into play once the mix is in use for growing seedlings and plants. High alkalinity water (i.e., water with pH >7-8 and bicarbonates above 100 mg/liter) causes growth medium pH to go up. The increase in pH can be detrimental to those species in Table 2 needing pH 5.4-5.8. Where alkaline water is a problem, growers can inject dilute acid to lower pH and counteract alkalinity. Keep in mind that alkalinity (level of bicarbonates) is more important than pH. High pH water with low alkalinity is much less a concern than water with both factors high.

    Some growers use nitrogen fertilizers to manipulate pH. Fertilizers supplying >50% NH4 (e.g., 15-15-15, 15-16-17, 20-10-20) are acidic fertilizers and high NO3 fertilizers (e.g., 15-0-15, calcium and potassium nitrate, cal-mag fertilizers) are basic fertilizers. Continued use of NH4 fertilizers tends to make the pH go down while continued use of NO3 fertilizers makes the pH go up. Generally these changes are not very large (0.5-1 pH unit) and they occur slowly. However, these fertilizers can be very useful in offsetting alkalinity or stabilizing pH in a desired range.

    Plants themselves can have an influence on growth medium pH. Many growers in Massachusetts have reported sudden drops in pH in soilless media growing geraniums. Oddly the low pH conditions which can develop as the geranium grows are the opposite of what geranium needs! In a North Carolina research project pansy, begonia, celosia, dianthus, and tomato caused the pH to drop while marigold, annual vinca, and zinnia caused the pH to increase. Sometimes these changes are large enough to cause a nutrient deficiency or toxicity.

    Fertilizing After Transplanting

    Bedding plants are commonly fertilized on a constant basis at 200-250 ppm N from one of the following fertilizers: 15-15-15, 15-16-17, 20-10-20, or cal-mag 15-5-15. These types of fertilizers are available from several different manufacturers. “triple 15” has lower levels of micro nutrients than the others and cal-mag supplies calcium and magnesium.

    A common fertilizer strategy is to begin fertilizing vigorous types shortly after transplanting. Small, slow growing types should receive lower rates (100-150 ppm N) or less frequent applications until they are well-established. To increase shelf-life it may be beneficial to cut the rate (ppm) in half at visible bud or about 2-3 weeks before sale. To avoid creating a nutrient deficiency, do a soil test before making a rate reduction.

    Douglas Cox
    Stockbridge School of Agriculture and UMass Extension
    University of Massachusetts, Amherst


    UMass Soil and Plant Nutrient Testing Laboratory

    UMass Extension Soil Test Report for Commercial Greenhouses

    Feeding Seedlings: Should I Fertilize Seedlings

    Fertilizing is a necessary aspect of gardening. Often, plants can’t get all the nutrients they need from garden soil alone, so they need a boost from extra soil amendments. But that doesn’t mean that lots of fertilizer is always a good thing. There are all kinds of fertilizers, and there are some plants and growth stages that actually suffer from the application of fertilizer. So what about seedlings? Keep reading to learn the rules of fertilizing young plants.

    Should I Fertilize Seedlings?

    Do seedlings need fertilizer? The short answer is yes. While seeds have enough power inside themselves to germinate, the nutrients essential to healthy growth aren’t usually present in soil. In fact, the problems that small seedlings suffer from can often be traced back to a lack of nutrients.

    As with most anything, though, too much fertilizer can hurt just as much as not enough. Make sure when feeding seedlings not to give too much, and don’t let granular fertilizer come directly into contact with the plant, or your seedlings will get burnt.

    How to Fertilize Seedlings

    Nitrogen and phosphorus are two very important nutrients when fertilizing seedlings. This can be found in most common fertilizers that are designed to promote plant growth.

    Don’t fertilize your seeds before they’ve sprouted (Some commercial farmers use a starter fertilizer for this, but you don’t need to).

    Once your seedlings have emerged, water them with a common water-soluble fertilizer at ¼ regular strength. Repeat this once every week or so, gradually increasing the concentration of the fertilizer as the seedlings grow more true leaves.

    Water all other times with plain water. If the seedlings start to become spindly or leggy and you’re sure they’re getting enough light, too much fertilizer may be to blame. Either reduce the concentration of your solution or skip a week or two of applications.

    Strengthen Seedlings Before Planting

    Start Slowly

    Harden off fragile seedlings over the course of 6-14 days. The idea is to expose plants gradually to outdoor conditions, each day incrementally increasing the time seedlings spend outside.

    Withhold water gradually over the course of hardening off. Don’t allow seedlings to wilt, but also don’t pamper them by keeping soil perfectly moist.

    Stop fertilizing seedlings 3-4 days before you plan to start hardening off. Don’t fertilize again until you plant seedlings into the garden.

    Provide Protection

    Initially place seedlings outdoors in a sheltered spot – protected from wind and direct sun. Each day following, expose plants to another 30-60 minutes of filtered sunlight. Work your way up to giving plants direct morning sun, followed last by noon-day sun. By the end of the hardening-off time frame, seedlings should be experiencing the same amount of sunlight they’ll receive in the garden.

    Bring seedlings inside for the first two nights. If shuffling seedlings from place to place proves too difficult, tuck them into a partly shaded spot for a few days. Great choices include a location under a tree or picnic table, a covered porch, or an area next to a building where the structure’s shadow will shelter seedlings. After 3-4 days, move the seedlings to a slightly sunnier site.

    Watch The Temperature

    Keep tabs on predicted nighttime lows. If temperatures dip near freezing, move seedlings indoors or cover with a spun-polystyrene row cover, which protects plants from frost while allowing water and some sunlight to pass. You’ll get the best frost protection when you mount the row cover so it doesn’t directly touch foliage.

    Unless freezing temperatures are forecast, plan to leave seedlings outside overnight by the third or fourth night. Place them near a building or beneath a table to provide some protection. By the sixth night or so, expose seedlings to night air without any protection.

    Time To Plant

    After seedlings experience a week or so of hardening off, you’ll notice stems are stockier. Tuck plants into the garden on an overcast or drizzly day when winds are calm. Water in seedlings using a fertilizer solution diluted to half strength.

    After planting, continue to protect seedlings if high winds, frost, hail or heavy downpours threaten. Shelter plants beneath buckets, row covers or cloches. A plastic gallon jug with the bottom removed makes a good cloche for a seedling.

    When to Start Using Fertilizers with Cannabis

    • Escrito por : Ciara
    • Crop articles

    In this article we’re going to talk about when to start using fertilizers with cannabis. People always ask us when they should start using fertilizers on their plants, but honestly it depends on your grow method, the strain and the phase that the plant is in.

    Depending on the phase your grow is in your plants are going to need certain nutrients in higher proportions; they need more Nitrogen in growth, and phosphorus and potassium for the flowering period. Cannabis plants absorb large quantities of these nutrients as well as others, so if they don’t get them through irrigation then they’ll probably end up showing deficiencies through stains on the leaves.

    To start using nitrogen during the growth phase you’ll need to wait for your little plant to grow the roots out enough so that it becomes slightly stronger. It won’t need much more than some humidity to germinate and grow during the first few days, but once it begins growing aster then you’ll need to start using a growth fertilizer.

    You should begin off with small dosages; if your product says 4ml/L for adult plants then you need to start off with 1ml/L, and only begin using it once the leaves on your plant have three points. Once those leaves appear you can start using your growth fertilizer in the irrigation water. Once the plant begins growing more then you should raise the dosage until you reach the maximum milliliters allowed, and always use it with every second watering.

    For the rest of the grow, regardless of what products you use, you will need to use them on every second watering or else you’ll burn out the roots. If you notice the plant getting yellow then you can use fertilizers twice in a row, but if it gets a dense dark green color then you’ll need to lay off on the fertilizers for a couple of waterings.

    Once the female flowers begin showing then you’ll need to begin using flowering fertilizers. Just like in the growth period, you’ll need to start off little by little until you reach the maximum milliliters stated by the fertilizer manufacturer, alternating between pure water and fertilizers.

    Each brand has a different range of products, so depending on the brand you go with you’ll need to use more or less products for both growth and flowering, although in this article we’re just talking about WHEN to use them.

    If you buy a product with root stimulants in it then you should use it during the first two growth weeks and for two weeks after every time you transplant. If you have a flowering stimulant then you’ll need to use it once you flip the lights to 12 until the first flowers start appearing.

    If your chosen range of liquids has a fattener with a high PK you’ll need to use it during the last phase of the flowering period, the fattening period.

    Author: Javier Chinesta
    Translation: Ciara Murphy

    How To: First Nutrient Feeding for Cannabis Seedlings

    In this video I explain when you should give your cannabis seedlings their first nutrient feeding. I also demonstrate how to mix the nutrients at the appropriate strength and pH level for seedlings.
    The first and most important step in this process is knowing exactly the right time to feed your seedlings their first bit of nutrients. If you do it too soon it could damage the plants and if you wait too late, the plants might exhibit some deficiencies. The best time to give the first nutrient feeding is when your plant has 3 nodes or 3 sets of fan leaves. At this point the plant can handle a low dosage of nutes.
    I always start with 1/4 strength of what the feeding chart recommends for the first feeding. So if the chart calls for 1 Tsp of CalMag per gallon, I’ll do 1/4 Tsp per gallon instead. Once it is time for the next nutrient feeding, I’ll do 1/2 strength, then 3/4 strength, until finally I am doing full strength for the rest of the grow.
    Once you have added and mixed your nutrients and coco wet ( if growing in coco based medium), you will want to pH your mix. This is crucial, and the desired pH will vary depending on the growing medium you use. In a coco based medium I pH to 5.8 and that works really well.
    Now that you have your nutrients prepared, it is time to feed the plants! Be sure to gently water so you do not move the soil around and disrupt the roots. Water a little bit at a time and stop once 20% starts pouring out of the bottom. At that point you have completed the watering. Also be sure to water all around the plant so that you cover all areas of your growing medium.
    And that is all you need to know about giving your cannabis seedlings their first nutrient feeding. Remember to only provide nutrients once every 2-3 waterings, and you will be able to grow a perfectly healthy and massive cannabis plant!
    As always, thank you for watching and until next time…
    Happy Growing!!!

    Dylan @ GreenBox Grown

    How to grow out your baby cannabis plants

    After your seedlings have started, you are going to need to grow out your plants. That includes making sure they have a healthy medium to grow in, ample room to grow, plus enough light, food, water, and a cozy temperature and humidity. This process is called ‘vegetation’. Let’s dig in.

    Transplanting Seedlings

    Keep your seedlings healthy by keeping the growing medium moist, but not soaked, and by spraying the leaves with water once or twice daily. Once seedlings have established roots and grown to around 4 to 8 inches tall, it is time to transplant your marijuana seedlings. Growing vibrant and healthy marijuana plants requires you do so. The growth period between seedlings and mature plants, prior to flowering, is called the vegetative phase.

    DIY: Sprout your own marijuana seeds with these tips from a master gardener

    Soil-less (hydroponic) growers will transplant mature seedlings into their preferred systems. The pH for soil-less gardens should be about 5.5-6.5. Indoor and outdoor soil growers will generally transplant seedlings into a size #1 through a #5 plant container. I grow in soil, both indoor and outdoor. When I transplant up, my soil mixture is one part (Pro-Mix) Coco Choir soil with one part (Fox Farms) Ocean Forest mix, which includes a fine blend of: earthworm castings; bat guano; fish meal and crab meal. A pH of 6.2-6.8 should be maintained in soil.

    The best light for vegetating cannabis

    When bringing plants outdoors, I like to get started as soon as the season allows. That means no more rain or freezing temperatures. I like to take the plants outside for extended periods during the day, over the course of a week or so, to let them get used to the bright sunlight and temperature variations of an outdoor environment. This is known as “hardening”,a process that keeps the plant from suffering too much stress (shock) when moving from one environment to another. While the marijuana plant is very hardy, shocking it can set its growth dormant for several days to several weeks.

    Clones from Bolder Cannabis of Boulder Colorado | David Downs

    It is important the plants have light for at least 14 hours a day in order to maintain vegetative growth and keep them from flowering. The growing season varies slightly by latitude. For instance, mid-summer days in the state of Washington are about 16 hours, while in southern California the mid-summer day is about 14 hours. Vegetative lighting preferences differ between indoor growers. Some growers prefer to use a lower watt High Intensity Discharge (HID) bulb for vegetative growth, say a 400w or 600w, while others might prefer to use the 1,000w bulbs typically used for the flowering cycle. The “Gavita” brand offers a professional line of lighting systems that are very popular with mainstream growers today. Likewise, brands such as Hortilux bulbs and Value Brite hoods offer more budget oriented brands.

    BACKYARD CANNABIS PROJECT: Get your plants in the ground or into pots

    Light Emitting Diode (LED) systems are gaining rapid popularity because of their low heat generation and high energy efficiency. The technology surrounding LED is also increasing, making them very viable for small indoor gardens as their price continues to drop. Some of the top selling LED brands include; Advanced Platinum, GalaxyHydro, Kind LED, Apollo Horticulture and King.

    How long to leave the lights on

    Some growers prefer to use a 24-hour light cycle for vegetative growth, others tend to leave the lights on about at least 16 – 18 hours. Regardless of what light cycle you use, just make sure that you have over 12 hours of light on your plants or their hormones will begin to trigger the flowering phase.

    Ideal temperatures and humidity for cannabis growth

    The temperature for outdoor growth should ideally range from a low of about 55 F to a high of about 85F. Early spring and late fall you can expect to see the low’s possibly dropping below 55F, while in mid-summer highs may exceed 85F. Fluctuations in temperature are okay, as long as they are not for extended periods. Methods to keep those ideal temperatures consistent throughout your growing season include plant blankets for cool nights and shade cloth for hot days.

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    Speaking of outdoor variables, excessive wind can damage your plants while excessive moisture can encourage the growth of molds and mildews. So stake your seedlings to support them in the wind and make sure soil has good drainage.

    Indoors, ideally, the temp should be maintained at 65F to 85F with a difference of no more than 20 degrees. Humidity for marijuana plants should be about 60% in the vegetative growth cycle.

    Feeding your growing cannabis plant

    Start adding nutrients to your watering routine now. Follow the directions of the products you are using, adding the nutrients conservatively as per the label, building up to the maximum dosage over time. Be careful not to overwater your plant and avoid combining so many nutrients that the plant loses its ability to uptake the additives. Generally, in the soil mix above, I use some calcium and magnesium, some seaweed extract, and a good vegetative plant growth mix specialized for marijuana growing. Botanicare, Advance Nutrients and Fox Farms are all reputable nutrient companies.

    Cannabis grows underneath LED lighting in Seattle, Washington | Jordan Stead

    Your plant will tell you whether or not you are treating it right by rewarding you with rapid growth in both height and new lush green foliage. On the other hand, too much or not enough water, or, too much or not enough fertilizer, and the plant will droop and begin to yellow or brown at the leaves. Keep your eyes open for any symptoms and make changes in your routine to correct any water or nutrient imbalance. Have fun, don’t try too hard, and let the plant do what it does best – grow!

    GreenState cultivation columnist Kevin Oliver is the co-author of “Idiot’s Guides: Growing Marijuana” (Alpha, 2016). Besides being founder/CSO of Washington’s Finest Cannabis and sitting on the Board of Directors for NORML, Oliver is also the executive director of WANORML/WANORML PAC — the Washington Affiliate of the National Organization for the Reform of Marijuana Laws.

    Plant Food 101: How To Feed Plants So You Get Big Buds And Huge Yields

    Just like humans need proper food packed with healthy nutrients to help us grow strong and vigorous, your plants also need the right foods.

    Feed your plants the right foods in the right ways and you too could see consistent yields of 3-plus pounds per grow light, like many growers today who follow these feeding guidelines.

    To help you on your path to successful growing, in this article we’re going to cover everything you need to know about plant food and what you need for your high-value plants and specialized strains, including:

    • What plant-specific nutrients do and why they’re so important for high-value crops.
    • How to know exactly what to feed your plants during every stage of their growth cycle to get maximum yields, potency and performance.
    • And common feeding mistakes, along with how to fix them as quickly as possible.

    Let’s start with the basics…

    What Are Plant Nutrients, What Do They Do, And Why Are They So Important?

    Just like food for people, your plants need food to survive, thrive, and grow into the high-value performers you want them to be.

    Nutrition and food can be broken down into three categories: macronutrients, secondary nutrients and micronutrients. Macronutrients are the big nutrients that are required for health and growth, secondary nutrients are slightly less important, and micronutrients are the small nutrients.

    For example, with people food, macronutrients are protein, carbohydrates and fats. These are the most important nutrients you must have to be healthy and to survive.

    For plants there are 16 important nutrients that can be broken up into macro- and micronutrients:

    The bottom line is, your high-value plants need macro-, secondary and micronutrients to thrive.

    A Quick Guide To Nitrogen, Phosphorus And Potassium (N-P-K)

    Once you get into growing strains of high-value plants, you will find that nitrogen, phosphorus and potassium are also commonly referred to as N-P-K.

    That’s because these are the three most important nutrients for plants. Without these three nutrients in the proper amounts, your plants will eventually die.

    Early on, growers of high-value plants recognized the importance of these nutrients in combination and so began formulating plant food with specific ratios in mind. When you pick up a bottle of base nutrients, you will often see the three numbers on the label:

    These numbers stand for the N-P-K ratio in the product. The first number is nitrogen, the second is phosphorus, the third potassium.

    Keep in mind, these are the ratios – not a specific amount in the product.

    If N-P-K are all essential nutrients for your plants, at this point you may wonder why the ratios in the bottle would make any difference at all.

    Why Your Plants Need Specific Nutrients For Each Phase Of Growth

    Your plants not only need the right nutrients, but they need them in the right ratios, only at specific times in their life cycle.

    To keep things simple, there are two main stages to your plant’s life and they each require a specific ratio of N-P-K for optimum performance:

    • Vegetative stage: high nitrogen, medium phosphorus, high potassium.
    • Flowering stage: low nitrogen, medium phosphorus (much less than most growers have been led to believe), high potassium.

    If all this seems confusing, don’t worry, the important thing to remember is this: You have to make sure your plants are getting the optimal levels of nutrition and the nutrients they crave during these times in order to keep them healthy, growing, and later enjoy a great harvest. That’s why scientific testing, research and development with the distinct strains you grow (as opposed to other typical food plants) is so important when choosing your nutrients.

    How Often Do You Need To Feed Your Plants?

    How often you nourish your plants will be determined by both the type of growing medium and the nutrients you are using. For example:

    • Soil growers: Some growers who plant their seeds in nutritious soil in a vibrant outdoor area may find they hardly need to feed their plants at all. You will have to keep them watered, though, and can add nutrients as needed when you water.
    • Soilless mediums: Using a soilless medium such as peat or sphagnum-based mediums, you’ll have to water and feed your plants often. When the top of the growing medium feels dry, it’s usually the right time to give them water.
    • Coco coir: Using coco coir, you’ll want to feed often, with ample runoff. Coco should remain wet and usually be fed at least daily. You’ll also want to use coco-specific nutrients.
    • Hydroponics: Your plant’s roots are interacting with water constantly, which also contains your nutrients. In some of these hydroponics setups your plants are feeding all the time.

    As you might imagine, answering the questions of when to water and feed your plants at this point can get complex and there are many variables based on the strains you’re growing, where you’re growing, the strategy you’re using, and the medium you’re growing in.

    How To Know Exactly What To Feed Your Plants For Strong, Healthy Growth And Maximum Yields

    In order to figure out exactly what’s right for your personal grow situation, the good news is that you don’t have to guess. There are experts that have done the legwork and experimentation for you.

    These are commonly called feeding schedules and they’re a very convenient way to get your grow going.

    In fact, here at Advanced Nutrients, we have three excellent ways for you to determine the optimum feeding schedule for your plants:

    1. Nutrient Calculator: When you use our nutrient calculator, you’ll quickly be able to see how much of what nutrients to feed your high-value plants growing hydroponically.
    2. BudLabs Mobile App: If you’d like to take our nutrient calculator into the grow room with you, this is the best way to do it. Simply download the app to your phone (available for both iOS and Android) and you’ll have everything you need in the palm of your hand.
    3. Customized Growing Recipe: To completely customize your grow recipe, you’ll want to use the free recipe generator we provide. With this one page, you can receive a completely custom recipe based on your experience level, growing medium (including coco coir, hydroponics, Pro-Mix/Sunshine Mix/soilless or soil) and more. It’s literally your step-by-step guide.

    Once you have the recipe you want to follow, the only thing left for you to do is visit a local store to find your nutrients and get started.

    A Quick Guide On How To Mix Nutrients

    It’s pretty simple to get your nutrients ready to use.

    1. Vigorously shake your nutrients: The base nutrients you’re using may have been sitting on the shelf for a while, so it’s a smart idea to agitate them to make sure the active ingredients aren’t accumulating at the bottom from sitting too long.
    2. Ready your reservoir: Get your pure, preferably reverse osmosis, or RO-filtered water reservoir ready. Depending on your setup, this could be your reservoir or the container you’re going to use for hand-watering your plants later.
    3. Measure out each nutrient as directed into the reservoir, according to label rate: Using an appropriate measuring device, pour the nutrient from the bottle into your measuring device and then into the water container.

    For example, when using pH Perfect® Sensi Grow Part A, the label states:

    Use 4 ml per liter during all weeks of vegetative growth.

    That means you pour 4 ml of the nutrient into 1 liter of water and use that mixture to feed your plants. Simple!

    How To Know If The Nutrients You’re Using Were Designed Specifically For Your High-Value Plants

    Many growers are not aware that there is a huge difference in fertilizers that were designed for traditional agricultural crops such as corn, soybean and wheat, and fertilizers that were developed for high-value plants.

    A study conducted by the University of Mississippi demonstrated the dramatic difference specialized fertilizers can make when growing specialized strains. It is the only scientific study of its kind, proving that the Advanced Nutrients fertilizers delivered 21 percent bigger yields when compared to regular fertilizers.You can .

    The fact is, in this day and age, there is no reason to use regular fertilizers for growing high-value plants.

    And whatever you do, don’t make the common beginner mistake of using something like Miracle-Gro for your high-value plants.

    Miracle-Gro nutrients and Miracle-Gro soil (or any “extended release” soil, really) will leave you with all kinds of nutrient problems — everything from burning your plants to starving them. Your best bet is to leave those plant formulas for the tomatoes and flowers they were intended to feed.

    Here Are Some Common Feeding Issues And How To Fix Them

    While growing great plants is not always simple, here’s a quick and simple list of some common feeding issues and how to fix them:

    • Underfeeding: If your plants are looking pale green instead of vibrant, then you could be underfeeding them. You need to give them more nutrients.
    • Overfeeding: Likewise, you could be overfeeding your plants and not know it. This is often accompanied by nutrient burn and could be caused by problems like nutrient lockout.
    • Nutrient lockout: This occurs when the nutrients you’re feeding your plants are unable to be absorbed and so they can’t feed. Discover what you need to know about nutrient lockout here.
    • Nutrient burn: When you give your plants too many nutrients and they end up with brown/black/dark burn spots on the tips of their leaves. This can happen if you don’t recognize signs of nutrient lockout and think plants are underfed, so you add more nutrients.
    • Overwatering: Your plants can be drooping because they’re starved of oxygen if their roots are sitting in stagnant water caused by overwatering. This is one of many plant root problems you can run into.
    • Nutrient deficiencies: Often looks like underfeeding in the form of droopy, sad, sick-looking plants. Goes hand in hand with underfeeding, but you could be lacking specific micronutrients even if you’re feeding them enough.
    • pH problems: Your pH levels are critically important to your plant feeding program. .
    • Don’t forget to flush! Many nutrient and feeding issues can be fixed by knowing how and why to flush your plants. Don’t forget to do this.

    Feeding Your Plants The Right Nutrients At The Right Time And In The Right Amounts Will Give You The Results You Want

    Plant food and proper nutrition is so important that it can mean the difference between losing a harvest or enjoying the most bountiful, potent yields of your life.

    It’s that important.

    So take the time to educate yourself on plant nutrition. Use the tips in this article and check out the recommended resources to see what a big difference the proper plant food and fertilizers can make, and you’ll be improving your growing results in no time!

    Did You Enjoy This Article? Sign Up To Our Free Newsletter To Get More Essential Gardening Tips.

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    Basic Seed Starting & Baby Plant Feeding

    Q: I’ll be starting basil and tomatoes under some LED fixtures that I can adjust to keep the lights just above the plants. I’ll use a timer to provide the appropriate amount of light each day (which I still need to research). My question is about feeding. I’ve heard you say that potting soil has almost no nutrients. So how should I feed my young plants? Once they’re outside, I’ll use my own compost (made from fall leaves), but I don’t want to use it inside the house. Is there some kind of granular feed you would recommend?

      —Tyler in Harleysville PA

    A: I have to thank Tyler for his timeliness; this is the perfect time of year to deliver a little primer on seed starting; and I’ll begin by suggesting that those lights be on for 16 hours a day, and then off to give the baby plants eight hours of darkness every cycle.

    Side note: His use of LEDs is clearly the Next Big Thing in indoor growing, but I don’t know a lot about them—and I already have several sets of four foot long fluorescent tube fixtures that work very well for me. However, the basic principle is the same: you want to keep the baby plants very close to your lights to insure that they get enough lumens, and that means you need lights that don’t get too hot. Old school incandescent bulbs would cook the baby plants in much the same way that the Easy Bake ovens of my childhood used 60 watt incandescent bulbs to bake cupcakes.

    Timing: start your seeds two months before you intend to put the plants in the ground. If you typically plant on May 1, your start date is March 1st. May 15th = March 15th; and in colder climes, April Fool’s for June 1st—so you don’t get fooled by a late frost.

    Tyler already seems to know not to use garden soil to start his seeds. It’s the worst. Using a light, loose soil-free mix allows for the maximum root growth and good drainage that produces healthy plants; and beginning the season with healthy vigorous starts gives you your best shot at long-term success. Trying to start seeds in clay soil and the infamous “sunny windowsill” always delivers weak, puny, leggy plants. You’ve got two strikes on you before the season even starts!

    There are many excellent seed-starting systems on the market, but I use old plastic nursery ‘six packs’ that I’ve collected over the years. They’re designed to hold moisture, drain well, and provide the kind of depth that allows plants to develop deep roots. (Plus re-using the containers gets rid of any potential guilt I might have about using plastic. By the time I throw an old six pack away, it’s in shreds!)

    Note: whatever you use to start your seeds, follow one rule: No egg cartons! They’re not deep enough and you’re not in kindergarten anymore!

    Fill the containers with a light, loose soil-free mix and sit them in water for a few hours until the mix becomes totally saturated. (You may have to put a dish or something on top to hold them down in the water in the beginning.) Then sow two seeds on top of the wet medium in each cell. (Don’t sow and then water; it can wash the seeds all over the place.)

    Cover the seeds with a little more mix, cover the containers with something like Saran Wrap (or put the lid on if it’s a little plastic greenhouse) and put them in a warm but not hot spot. Mid 70s F. is ideal. If you’re planning on doing this every season, heating mats are a great investment. They’re set to the perfect temperature to get the seeds sprouted quickly without cooking them. All my seeds are started on mats.

    Place your freshly-sown and now covered containers in a low tray that holds water, and add water whenever the tray gets dry. Check them every day, and take the wrapping or cover off as soon as you see the very first sprouts. Immediately stop using any bottom heat and get your plants under bright light—with no more than an inch between the lights and your baby plants.

    Don’t worry about the seeds that haven’t sprouted yet; any viable ones will pop up soon. Keep the uncovered plants close to the lights and cut back on the water.

    Now: when and how do we feed?

    Most of the high-quality bagged organic/natural potting and seed starting soils I’ve seen and used already contain small amounts of natural nutrients like worm castings and compost that feed the baby plants perfectly for the first few weeks, making life easier and the young plants healthier. And seeds also contain a lot of their own ‘starter food’, so even if you don’t have a little bit of natural food in your seed-starting mix, don’t add any food until the plants are a few inches high and have at least four true leaves.

    (Note: Avoid seed-starting and potting soils that contain chemical fertilizer, which is what you’re most likely to find at mass merchants. Take a pass on these and keep looking; it’s better to start a week later than to feed your baby plants nasty stuff in utero. Same goes for those ‘water-holding crystals’; I’ve never seen any evidence that they work (and they creep me out).

    Then before we feed, we ‘thin’. This is the hardest chore emotionally in seed-starting, but it has to be done. Use a small pair of scissors to snip off the weakest looking sprouts until you only have one plant per cell. Choose the shortest, stockiest, best-colored specimens for survival; snip off the taller, more spindly ones. And be sure to snip the losers out—don’t yank them out or you risk killing the other plant!

    Then get a bag of high quality compost or worm castings and make ‘tea’. Fill an old sock with the compost or castings, let it sit in a quart of water for a few hours and then use that ‘tea’ to water and feed your plants. (You can use your own compost if it’s completely finished, but most gardeners don’t have finished compost this early in the season.)

    Depending on the size of your original seed-starting cells, you might also want to pot your plants up into larger containers, which is never a bad idea if you have enough room under your lights.

    This is a great time to mix some worm castings or compost in with the additional potting mix you’ll be using. (Notice how gently we’re feeding early on?)

    Note: For tomatoes, add all the new soil on top, burying part of the stem and keeping the roots down at the very bottom. But with all other plants, add the new stuff at the bottom and maintain your original soil line. (Read a couple of our tomato articles to learn why.

    Hardening off: As planting time approaches, take your babies outside for a few hours a day for several days, and then leave them out overnight as soon as nighttime temps remain in the 50s. When the calendar says it should be OK and the ten day weather forecast confirms that it is OK (nights in the 50s), you can plant them outside. Don’t rush the season; tropical plants (like peppers, tomatoes, eggplant, melons, cukes….) do poorly if they’re exposed to nighttime chill early in life.

    Then wait a week to let them get settled before you actually ‘feed’ them. That food can be a ‘mulch’ of two inches of high-quality compost or one inch of worm castings or a balanced non-chemical fertilizer. If you’re using a granulated fertilizer, spread the directed amount on the surface of the soil and then cover it with some compost or soil to activate it to release its nutrients faster.

    For more detailed info on all of these steps, read our earlier articles on seed starting under the letter ‘S” in our archives.

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