Foliar Feeding Guide for Cannabis Plants
Not to be confused with foliar spraying which is basically the same but refers to any solution that can be sprayed, generally used to deal with bug-infested plants by applying an insecticide or fungicide via foliar spray, foliar feeding consists of delivering macro and micronutrients to your plants by spraying the nutrient solution directly onto the leaves, resulting in healthier leaves and allowing you to fix nutrient deficiencies faster. Now, a lot of growers believe that foliar feeding can be better than regular feeding, but is it true?
1. What is Foliar Feeding and Foliar Spraying?
Foliar feeding involves spraying the leaves, instead of watering the soil, with a nutrient solution and it’s a quick and effective way to deal with nutrient deficiencies, this happens because the leaves can absorb nutrients much faster than the roots, although they’re limited by the size of the stomata, unlike the roots. Foliar feeding became popular in the 1950s when researchers at Michigan State University found that the leaves are a super-efficient organ of absorption; While the amounts they can absorb are relatively small when compared to watering the substrate, the efficiency is higher, reaching about 95%.
Despite what the scientists found, not all growers agree, in fact, cultivators have found that most products designed to be used as a foliar spray don’t include a surfactant to help the solution hold on to the leaves so the nutrient solution drips off the leaves almost immediately and when this happens, the leaves cannot absorb the nutrient solution properly but the solution still drips onto the substrate and is then absorbed by the roots. This means that foliar feeding can help you deal with nutrient deficiencies and may be used a couple of times to maintain the leaves healthy but should not substitute regular feeding.
Apart from foliar feeding, there’s also foliar spraying which is basically the same method as foliar feeding but it’s used to apply fungicides or insecticides to combat mold, bugs or diseases. There isn’t really a difference between foliar feeding and foliar spraying besides why you’re using it and the frequency you should apply the solution, both of them are basically foliar sprays but one is used to feed your plants while the other is used to combat bugs or mold.
2. When is The Best Time To Foliar Spray Or Foliar Feed?
If you’re growing outdoors, the best time for foliar spraying or feeding is early in the morning or late in the evening because this is when the plant’s spores are fully open; If you’re growing indoors, the best time to spray your plants is 1-2 hrs before the lights turn off or 1-2 hrs before the lights turn on, this is due because at this time the plant’s pores are fully open, which allows for a quicker absorption when compared to spraying during the day (or when the lights are on).
The best time to foliar spray is 1-2 hrs before the lights turn off or 1-2 hrs before the lights turn on.
Keep in mind that it’s not recommended to foliar spray when your plants are getting direct sunlight because, due to the “lens effect” caused by the water droplets, the light can end up burning the leaves and may degrade the nutrients or substances in the solution.
3. When You Should Foliar Spray
As mentioned, foliar feeding cannot substitute soil applications but under certain conditions, it may have an advantage over regular feeding and there are three main scenarios.
Limited Nutrient Absorption
Foliar feeding is recommended when something is limiting nutrient absorption by the roots, this may happen when the soil’s pH is high or low, temperature stress, high or low soil moisture, root diseases or a pest infestation that can affect nutrient uptake.
For example, nutrient availability in the soil is reduced when the soil’s pH is too high or too low, so under this condition, foliar feeding might be the best way to deal with this until you can fix the pH.
Foliar spraying is a great way to deal with nutrient deficiencies due to the fast absorption, as mentioned, the leave’s nutrient absorption can be as high as 95% which is 8-9 times higher than the root’s absorption efficiency, making it a quick (but temporary) way to deal with nutrient-deficient plants.
Foliar Feeding Stimulants And Growth Boosters
As mentioned, foliar feeding should not substitute regular feeding but due to the fast absorption, it’s a fast and effective way to provide your plants with specific nutrients or vitamins in the form of growth boosters or stimulants for each growth stage. Besides providing macro and micronutrients, stimulants and growth boosters will also help the leaves and branches grow healthier, and provide the extra boost your plants need which can improve plant strength, yield, and quality.
Foliar Spraying Against Insects and Mold
Foliar sprays are the best way to deal or prevent pests and diseases such as spider mites and powdery mildew. One of the most popular substances used is neem oil which acts both as treatment and prevention while having the advantage of being 100% natural and also having anti-fungicidal properties.
A lot of growers use neem oil or similar products and sometimes mix it with aloe vera juice and an emulsifier like potassium silicate to dissolve the oil and make it easier for the plants to absorb; By applying a solution like this one week during the vegetative stage can result in stronger plants and increase resistance against diseases and pests, but its use it’s not recommended during the flowering stage because it can affect the flavor and aroma of the buds.
Also, a foliar spray made with insecticidal soap such as potassium soap is an excellent way to take care of harmful bugs, and it’s particularly effective against aphids which are very common against aphids. This means that mixing different products can result in an even more effective solution, for example, mixing neem oil and potassium soap can get rid of bugs and also prevent future attacks.
Have in mind that you’re not limited to just neem oil and potassium soap, there are a lot of natural ingredients such as cayenne pepper, cinnamon oil, and garlic which can combat pathogens and insects without harming your plants and, if you don’t want to make your own mix, you can definitely find a natural solution in your local grow shop.
4. The Limitations Of Foliar Spraying
Now that you know the best time to foliar spray and when to do it, it’s time to know its limitations because despite the high efficiency and quick absorption, foliar spraying has its downsides too and they are:
Limited Nutrient Dose
Nutrients applied via foliar spray will not provide the entire nutrient dose your plants need so you will have to water the substrate with a nutrient solution in order to meet the entire nutrient requirements.
Leaf burn (aka phytotoxicity)
Applying a strong nutrient solution via foliar spray can result in leaf burn due to the water evaporating and leaving the nutrients on the leaves.
Cost and applications
In order to avoid leaf burn, for example, you will have to foliar spray smaller nutrient doses more often which is impractical and can cost more than regular feeding.
5. What Type Of Sprayer Should I Use?
There are two main types of sprayers used for foliar spraying and both are useful depending on the situation. The first type is the regular hand sprayer that you can easily find everywhere, this type can take between 500 ml to 11 L of solution and are small yet handy sprayers that will work great if you need to spray just a couple of plants or need to be more precise and not spray the buds.
The second type is pump sprayers which can be a bit harder to find but are super convenient because it usually comes with a “sprayer wand” which allows you to spray your plants from all sides without much effort.
Now, there isn’t something as the best sprayer because the best thing would be to get both types and use them as you need to; This is because sometimes you will need a bigger sprayer such as the pump sprayer to foliar spray all your plants more easily but sometimes you need to be more precise and spray just a couple, in this situation the small hand-sprayer would be better so the best thing would be to have both of them available.
After a couple of years of using different types of sprayers for foliar applications, we can now confidently say that in almost every single circumstance a pump sprayer will do a better job and just make a grower’s life easier. These types of sprayers can be easily sourced from any garden supply store, hardware store, online, or at a specialized hydroponics store. They cost next to nothing and make any sort of foliar application so much easier. Do yourself a favor and go and grab one, and make sure it has one of the spray wands (makes full plant coverage a breeze). Trust us when we say you will definitely not regret it.
6. Homemade Foliar Spray Recipes
In case you don’t want to spend but still want to take advantage of the benefits of foliar spraying and foliar feeding, here are a couple of natural homemade recipes to help you get the best results:
Natural Growth Stimulant Recipe
For this natural growth stimulant you will need:
|10 g of Kelp meal||0.5 g of liquid Silica (optional)|
|5 g of Aloe Vera juice||5-10 g of Alfalfa meal (optional)|
Soak 10 grams of Kelp meal in 1 liter of water for around 3-5 days; Kelp meal contains almost every macro and micronutrient your plants need as well as organic PGR’s (plant growth regulators). Once 3-5 days pass, add 5 grams of Aloe Vera juice which works as a surfactant and also contains many micronutrients, mix well and the foliar spray is ready for use.
You can also add 0.5 grams of liquid silica to the spray which will help strengthen the cell walls, resulting in stronger branches and increasing resistance to pests and diseases. Alfalfa meal is another great option because it contains Triacontanol which is another growth stimulant. Keep in mind that this recipe should be used when the lights turn off and you should stop using it 2-3 weeks before your plants enter the pre-flowering stage.
Natural Insecticide Recipe
If you’re dealing with a bug infestation or want to prevent one, here’s a great recipe; You’ll need:
- 100% natural Neem oil;
- Peppermint castile soap or any type of organic insecticidal soap;
- And warm water.
Fill a sprayer with 1 L of warm water, add 0.6-1 ml of castile soap and gently mix the solution. Once the solution is properly mixed, add 1 teaspoon of Neem oil, then close the sprayer and shake until the neem oil is combined. Once the soap and oil are properly combined the mixture is ready for use, just remember to always shake the bottle before spraying. If you’re dealing with a bug infestation, spray once a week until the bugs are gone and if you’re using it as a prevention measure, spray every 2 weeks, remember that you should not spray the buds!
Natural Fungicide Recipe
If instead of dealing with bugs (or preventing them) your goal is to get rid of mold, here’s what you’ll need:
|1 L of warm water||1 ml of Rosemary oil||3.5 ml of 100% natural Neem oil|
|0.6-1 ml of castile soap||1 ml of Peppermint oil||3.5 ml of olive or almond oil|
The process is basically the same as the recipe mentioned before with the exception of the extra ingredients. So first of all, fill the sprayer with warm water then add the castile soap and gently stir. Once the soap is mixed in, add the rosemary oil, peppermint oil, neem oil, and olive or almond oil and shake until everything is well combined and the spray is ready.
This foliar spray’s use is the same as the one mentioned before, so remember, spray once every 7 days if you’re fighting mold and once every 14 days as a preventive measure but never apply this foliar spray on the buds because it will alter their taste and aroma. Don’t worry if you do not have access to rosemary or peppermint essential oils, or olive or almond oil. These extra ingredients do help when using a fungicidal foliar spray, but they are not 100% necessary or needed. You can use the same basic insecticide recipe above and you should still see great results.
7. Top Tips To Improve The Efficiency of Foliar Spraying
There are several factors that can affect the effectiveness of foliar feeding or foliar spraying, so it’s important you keep the following factors in mind in order to foliar spray more effectively:
Don’t Forget About Surfactants
Surfactants, or “wetters”, are compounds that can act as wetting agents that help a liquid spread more easily and when talking about foliar sprays, they contribute to a more uniform coverage of the leaves while also increasing the retention so, in order to avoid wasting any product that you wish to apply as a foliar spray, it’s highly recommended to mix a surfactant into the solution. The surfactant that we normally choose to use with cannabis foliar sprays is insecticidal soap. (never use other types of soap like dishwashing liquid or laundry soap. These will have a negative impact on your crop).
But, what exactly is insecticidal soap? Insecticidal soap is either a store-bought or homemade solution that can be added to foliar sprays to help prevent or treat insect and pest infestations. They help with controlling and killing many of the common pests that can affect a cannabis crop such as spider mites, mealybugs, aphids, and whiteflies. Insecticidal soaps work by penetrating the exoskeleton of the insects and effectively drying them out, which causes dehydration and cell collapse. Although finding organic insecticidal soaps is easy and budget-friendly these days, many cultivators like to make their own homemade options. All you need is a pure soap with fatty acids (unfragranced is best). Liquid Castille soap works perfectly here (we recommend Dr. Bronners). Mix 3 tablespoons of the soap with 1 gallon of distilled or RO water and 1 tablespoon of vegetable oil. Give a good stir or shake up and hey presto you have yourself your very own, homemade, insecticidal soap.
Find The Best Time Of The Day
Avoid spraying when it’s too hold or too cold; As mentioned, it’s not recommended to foliar spray when the plants are getting direct sunlight but you also have to have the temperature in mind, so never spray when the temperature is above 26°C.
In hot temperatures the pores on the leaves will be almost closed, making foliar sprays less effective and, when it’s too cold, foliar sprays may promote mold so it’s recommended that you spray a couple of hours before the lights are on or a couple of hours before the lights are off; It can also be a good idea to turn off the fans for an hour or two for your plant to better absorbs the solution.
When growing outdoors, do not spray if you’re expecting rain or strong wind because it can wash away the spray solution, so make sure the weather is fine or wait for the stormy weather to pass to avoid any major disturbances.
Spray With The Appropriate Droplet size
You should use a nozzle that sprays medium-sized droplets to cover a larger area and increase efficiency, this means that if you want to improve efficiency, the droplets should not be smaller than 100 microns or bigger than 175 microns. One of the main upsides of buying a high-quality garden sprayer is the control you have over the droplet size. Head over to your closest garden supply store or hardware big box and check out the range they have on offer. We recommend splashing out just slightly here. You don’t need to buy the most expensive option, but it’s best to grab one with adjustable droplet size. WIth $20 or so dollars you should be able to grab a gallon-sized sprayer with an extender wand (also super handy) and an adjustable droplet size.
Spray Volume Is Important
Spray volume can affect nutrient absorption efficiency so you should foliar spray until the whole canopy is covered, making sure you spray both sides of the leaves; Just remember that you shouldn’t spray too much, making sure that the nutrient solution does not drip off the leaves.
Always Follow The Manufacturer’s Instructions
Some commercial products may be safer to use than others so always follow the guidelines to avoid harming your plants. Also, make sure that you use protection such as gloves, mask, and eye gear if needed. You should also make sure that the product is safe for consumption because some products may be safe for ornamental plants but may not be safe for consumption.
Adjust The pH Of The Foliar Spray Solution
Nutrients in the foliar spray must be in their soluble form for the plant to be able to absorb them and the pH not only affects the nutrients’ solubility but also their interaction with other components of the water, so it’s essential you adjust the pH of the solution. According to the nutrients or substances, it contains. Canna bis like a different pH range depending on the method of cultivation. If you are growing in soil or a soil mix then keep the pH of any feed water and foliar spray inside the range of 6.0 to 7.0. For coco-coir cultivation, it should sit between 5.5 to 6.5, and for pure hydro, it should be somewhere between 5.8 to 6.2. These ranges also change slightly depending on the stage of growth the crop is at, so for all the relevant info take a look at the guide below.
8. Foliar Feeding Quick FAQs
What Does it Mean to Foliar Feed a Cannabis Crop?
In layman’s terms, it means to feed the crop the nutrient it needs to survive and thrive through a spray form directly to the leaves. The stomata (the leaf pores) open and allow for the plant to get direct nutrient nourishment rather than indirectly from the root zone.
What Are The Advantages of Feeding Through Foliar Spraying Over Root Zone Watering?
There are a couple of marked advantages of foliar feed when compared to regular watering. This does not mean that you should stop regular watering and switch totally to foliar feeding, but there are some situations where foliar can give an advantage to the crop. If a singular plant, or the entire crop, is displaying signs of a nutrient deficiency then foliar feeding can make a huge difference. A nutrient lockout can be caused by a few different issues at the root zone, meaning any feed water added to the roots may not provide the correct nutrient balance. If the growing medium pH balance is off, or if there has been a buildup of salts then the plant can suffer.
With foliar feeding, we are able to bypass the root zone and apply the feed directly to the plant’s leaves where it can be absorbed. This can be done at the same time as flushing the medium to bring it back to a good baseline. Waste is reduced as foliar feeding is much more efficient than root watering. Runoff is cut down, which not only saves you money but is also great for the environment. It’s much easier for the plant to access the nutrient, and the plant uses much less energy
Can Foliar Feeding Replace Regular Root Feeding?
In theory, yes there is nothing stopping you from going the whole hog and just using foliar feeding at all times for the nutrition of your crop. But, there is a reason why commercial growers do not use foliar feeding at all times. It is simply not very practical and takes a lot more work than regular root zone watering and feeding. So, while there is a time and place for foliar feeding, it should be used in conjunction with root zone watering and not exclusively.
When is The Right Time To Foliar Feed?
There are certain times when you should and should not foliar feed your plants. For outdoor cultivators, early morning or late evening is perfect. For indoor growers, the 30 mins just after the lights turn OFF, or around 1 to 2 hours before the lights come ON is perfect. You want the plant to suck up all the feed water before the lights turn on. If you feed during the hottest part of the day (or when the lights have been on for a while) you run the risk of burning the plants, stunting the growth of the plants, and ultimately reducing the yield and potency.
What is The Proper Technique For Foliar Feeding?
Three main points here:
- Cover the whole plant, but don’t leave it dripping.
- Use as fine a mist as possible (buy a good quality garden sprayer)
- If possible, move your plants outside of the tent or grow area.
Are There Any “DO NOTS” When it Comes To Foliar Feeding?
We have run through a couple already, like feeding with the lights ON, and using a cheap sprayer. But, there are a few other “do not’s” you should keep in mind when foliar feeding.
- Do not use foliar feeding in the last 3 weeks of the flowering period. This can lead to issues with proper flushing and could have an impact on the final flavor of your buds. If you do decide to foliar feed at any time during the flowering period, be very careful not to spray the budding sites. Keep them protected, it’s where the gold grows!
- Be very careful with the strength of your feed spray. Remember, the companies that produce the nutrients that we add to the feed water are businesses, and they make their money by selling as many of the nutrient bottles as possible. This means that they are prone to over recommending the strength of the solution. If your plants are very young, I would stick to 25% of the stated dose, and only move up to 50% when they are fully in the vegetative growth stage.
- Foliar feeding can dramatically and quickly raise the relative humidity of your growing space. Keep a hygrometer near at hand and stay vigilant, as high relative humidity can lead to all sorts of issues. If possible, remove your plants from the grow space to spray them.
9. In Conclusion
Foliar spraying your cannabis plants can be a great way to combat mold, bugs and pathogens, and it’s also a great way to correct minor nutrient deficiencies. Just keep in mind that the best way to feed your plants is by watering the soil, foliar feeding should be used as a complement or give that extra boost your plants need to produce dense and super resinous buds.
If you have any foliar spray homemade recipes feel free to help fellow growers by leaving a comment in the comment section below!
Foliar spraying and cannabis
It’s inevitable that at some point, almost all cannabis cultivators will find themselves in the position of needing to apply a foliar spray of one kind or another to their plants. There are many potential reasons for this: you could be in need of a fungicide or an insecticide; or maybe you want to fertilise, correct a nutrient deficiency or just give lacklustre plants a bit of a boost.
Whatever the motive for spraying, we think it’s worth doing the job properly, and there are some basic measures we should take every time to make sure we get the best possible results and avoid damaging our plants. We’ll deal with these ten fundamental points first, then go on to talk in a bit more depth about foliar application afterwards.
A small spray bottle working
The do’s and don’ts of foliar spraying
1. Do spray in low light, if you’re growing indoors, the best time will be at the beginning or end of the dark period before the lamps have fully warmed up. In outdoor cultivation, it’s best to spray early in the morning or otherwise late in the evening, rather than in full sunlight and during the hottest part of the day. This avoids any burning of the leaves due to the lens effect produced when strong sunlight hits water droplets and magnifies.
2: Don’t spray when it’s too cold or too hot. The ideal temperature for foliar application is around 20-24ºC. In hotter temperatures, the stomata are more likely to be closed, meaning they can’t absorb nutrients as effectively while spraying in cool weather can create conditions that favour fungal growth, something we most certainly want to avoid. For this reason, it’s always better to spray first thing in the morning and allow the plants to dry during the day, rather than applying at the end of the day, which can leave the plants soaking wet all night long in low temperatures.
3. Don’t spray in rainy weather, in high wind or with the ventilation running. Rain will obviously wash away, or at best dilute your spray solution, thus reducing its effectiveness. Save your solution and wait for the rain to pass before spraying. Windy conditions or powerful fans indoors will carry much of your spray mist away from the plants, meaning not only a waste of solution but more importantly, an ineffective application with incomplete coverage. In a light wind outdoors, stand upwind while spraying to minimise contact with the product and let the wind carry the mist towards the pants. Always be aware of your surroundings and other people, pets, etc. when spraying.
4. Do spray the whole plant, paying particular attention to the undersides of the leaves, where the stomata are located. In addition to being able to take in nutrients via the stomata, plants are also able, to a lesser extent, to absorb through the epidermis on the upper side of the leaf as well as the stems and stalks.
5. Don’t use nutrients at full-strength. If you’re foliar feeding with fertilisers intended for application to the substrate, it’s always a good idea to start with by using 50% of the recommended dosage rate to avoid burning the foliage with excess nutrients. Always use accurate measuring tools, don’t try and guess the amounts!
6. Do test on a single leaf before spraying the entire plant. It’s always a good idea to spot-test new and unfamiliar products to make sure it’s not going to have an adverse effect on the whole plant. Simply apply to one leaf or a small area of the plant and wait, if there’s no damage after 24 hours then it’s probably safe to apply all over.
7. Don’t spray during flowering. As a general rule, avoid wetting the buds of our cannabis plants at any time during the flowering cycle, mould is far more likely to infect and damage the flowers as a consequence, not to mention the likelihood of traces of the product remaining in the finished buds. Outdoor growers, on the other hand, need to be more realistic about spraying in flower, and in rainy climates, the issue of getting the buds wet is rather academic. The plants will inevitably get soaked at some point, and often a grower’s only chance to save the crop is by spraying an organic, residue-free fungicide to try and prevent mould. It’s of vital importance to always respect the safety period specified by the manufacturer.
8. Do use a surfactant or wetting agent of some kind when spraying for better coverage. Adding a few drops of horticultural soap, plain dish soap (free of perfumes and dyes and not antibacterial) or yucca juice to your spray solution will reduce surface tension in the liquid, thus allowing a more even coating of the surface and preventing beading, where large droplets form on the leaf and make absorption difficult.
Surface tension causes beading of water droplets
9. Do use a fine spray for a more even coverage when foliar feeding. A slightly coarser spray should be used for compost tea and beneficial microbe application, which requires a larger droplet size to achieve effective inoculation.
10. Do follow safety instructions. Make sure your garden is a safe one by fully complying with the manufacturer’s guidelines on proper usage and storage. Depending on the product used, it may be necessary to wear protective eye gear, gloves or a face mask to avoid inhaling particles. Remember that just because a product is organic, it doesn’t necessarily mean that it’s safe for human consumption.
Plant showing signs of nutrient deficiency
While it’s no replacement for feeding the roots and incorporating plenty of organic matter in the soil or substrate, foliar feeding has become widely accepted among horticulturists and agriculturists as a fast-acting and highly effective form of supplementing plant fertilisation in the short term, particularly for the supply of secondary nutrients like calcium, magnesium and sulfur; and micronutrients such as zinc, manganese, iron, copper, boron, and molybdenum.
Back in the 1950s scientists at Michigan State University proved conclusively the effectiveness of foliar feeding in experiments. They did this by spraying plants with radioactive phosphorous and potassium, and using a Geiger counter they were able to monitor absorption, movement and nutrient use. They observed that the nutrients were transported at a rate of approximately 30cm an hour to all parts of the plant. The study showed the foliar application of nutrients to have a 95% effectivity of uptake as opposed to 10% with nutrients applied to the soil via irrigation. Other studies have demonstrated a 65% uptake of nutrients just 25 minutes after application to foliage.
Stomata on the underside of a leaf
Another major benefit of foliar feeding is that when nutrients are applied to the foliage, it encourages plants to exude more carbohydrates into the root zone, which in turn increases microbial activity in the root area, working to increase nutrient uptake from the soil.
Due to the quick results obtained, foliar feeding is very popular with gardeners as an instant fix to correct deficiencies, delivering nutrients directly to the foliage in a plant-ready form when the plant needs them most, but without adding more fertiliser to the soil, where it could contribute to a build-up of nutrients and the resulting lock-out, only making the situation worse.
Safety first! – Always wear protection if specified.
Fungicides and insecticides
Many plant problems with pests and diseases can be solved with a foliar application of a fungicide or insecticide, however, any experienced grower will tell you that prevention is the key and regular use of organic preventive products will help greatly towards a trouble-free grow and happy harvest. Fortunately, many organic products are equally useful as preventive measures as they are at combating existing issues.
Neem oil is a widely available organic insecticide (and to a lesser extent a fungicide) that can not only be used to respond to pest attacks but also forms an important part of an approach known as IPM (Integrated Pest Management) employed by many organic cannabis farmers. In a typical organic IPM spray, neem oil is combined with aloe vera juice and potassium silicate (as an oil emulsifier), to make a solution that is sprayed weekly throughout vegetative growth to strengthen plants and reinforce them to better withstand pathogens and pests. Food grade essential oils like cinnamon or rosemary can be added for increased repellant properties and improved efficacy against mould.
Potassium soap is another popular and widely used non-toxic option to kill insects, particularly effective against soft-bodied sap-sucking insects like aphids. A top tip is to spray aphid infestations in full sunlight (there’s always an exception to the rule!) to get rid of them extra-fast, and always use with soft water (with a low calcium carbonate content) to avoid precipitation of the solution. Other products like Trabe’s Aliosan, with garlic as its main component, work as repellents to keep pests at bay and prevent an attack. Effective organic solutions are also available for the treatment of spider mite infestations (Spider Mite Control; Spider Plant), alongside biological controls based on Bacillus Thuringiensis like Cordalene by Trabe for the prevention of caterpillar or budworm attack.
If we’re looking for organic fungicides to help combat botrytis, powdery mildew, and other fungal pathogens, we can choose from a wide range of products incorporating natural ingredients such as propolis extract, horsetail, nettle and cinnamon essential oils to help us in our fight against mould.
Test by spraying a small area before applying to the whole garden
Stimulators, boosters and microbial inoculants.
An ample selection of plant growth stimulators and boosters suitable for foliar application are available to increase vigour, boost growth and reinforce plants’ immune systems, these include products such as Acti-Vera from BioBizz, Cannabogen’s Delta 8 or Vita Race by Plagron, all suitable for foliar application during vegetative growth to encourage bigger and healthier plants.
Another foliar approach to plant health is to inoculate plants with beneficial microbes which, as well as boosting growth and plant resistance, will also help to protect against attack by diverse pathogens. Products like B+ by Jumus Organix or Pure by OG Tea contain a blend of beneficial microorganisms ready to mix with water and designed to be applied to the foliage of cannabis plants for great results.
Alternatively, if we’re on a budget we can make our own DIY foliar stimulator at home by simply liquidising aloe vera leaves with water, or by researching recipes for compost teas, botanical teas, fermented plant juices or seed sprout teas that can safely be applied to the foliage to great benefit, with minimal cost and environmental impact.
Choosing a sprayer
For small gardens, where you’ll only be spraying a few plants, a handy 750ml spray bottle will be sufficient for proper treatment. Larger gardens with more plants to spray will require a hand-pumped pressure sprayer: these are available as a 2-litre bottle or in a 5-litre version with a shoulder strap that’s comfortable to carry and perfect for outdoor cultivation, with a spray wand that allows growers to access all of the plant and spray the underside of leaves efficiently.
The Aquaking 5 litre pressure sprayer
Always make sure to wash the sprayer well both inside and out after every application, this will not only maintain the equipment in tip-top condition but will also prevent any problems of compatibility and reactions between different products.
I hope this brief guide will be some help in your garden. Remember, a well-conceived and consistent spray regime can contribute greatly towards improving plant health and achieving a problem-free harvest, but make sure to use products responsibly, always following the instructions and respecting your own health, that of others, of our plants and of the environment in general. Happy spraying!
Respect the environment and spray responsibly!
The articles published by Alchimiaweb, S.L. are reserved for adult clients only. We would like to remind our customers that cannabis seeds are not listed in the European Community catalogue. They are products intended for genetic conservation and collecting, in no case for cultivation. In some countries it is strictly forbidden to germinate cannabis seeds, other than those authorised by the European Union. We recommend our customers not to infringe the law in any way, we are not responsible for their use.
An Introduction to Foliar Feeding Cannabis
Foliar feeding is a method of nourishing your plants by applying nutrients directly to the leaves. Cannabis leaves readily and swiftly absorb nutrients, allowing sick plants to heal quickly or healthy plants to thrive. Below we will explore:
- The benefits of foliar feeding in contrast to other methods
- When to foliar feed cannabis plants
- How to foliar feed your home garden
What Are the Advantages of Foliar Feeding?
With other feeding methods, cannabis typically absorbs nutrients through its roots. However, foliar feeding delivers nutrients directly to the leaves where they are taken in by the stomata.
Stomata are the pores found on the epidermis (skin) of the leaves. Generally, the stomata are responsible for the gas exchange between carbon dioxide and oxygen, but when they’re open, they can also take in nutrients.
These stomata can absorb the nutrients at a rapid pace, faster than top dressing nutrients or liquid feeding. You can also easily isolate and treat specific plants in your garden that are showing deficiencies without having to feed your entire garden.
Foliar feeding cannot replace all other types of feeding, but it’s a great tool for cannabis growers to have on-hand, especially when plants exhibit signs of deficiency.
When’s the Right Time for Foliar Feeding?
Foliar feeding works wonders when it comes to raising your plants to their full potential, but only when they are vegging or in the first few weeks of flowering. You don’t want to foliar feed your plants with developing buds and risk nutrient residue contaminating your hard work.
Once again, if you notice any plants showing signs of nutrient deficiencies, foliar feeding is a great solution. Plants most commonly display calcium/magnesium deficiency or a nitrogen deficiency, which can be remedied with a quick foliar spray.
Foliar feeding can also be used as a preventative tool to keep your garden thriving. This is accomplished by applying an array of macronutrients that will help provide your plants with a well-balanced diet.
How to Use Foliar Feed Spray on Cannabis Plants
To use foliar feeding correctly, you’ll first need to understand a few foundational tips and tricks.
When to Use Foliar Spray
Stomata are not always open, which limits the time frame in which you can apply your nutrients. Most gardeners advise that you spray in the evening time. If growing indoors, the stomata will take about 15-20 minutes to close up after the lights turn off, which gives you time to apply the nutrients without stressing the plants. Outdoors, you can start spraying in the late afternoon when the sun is descending and not directly hitting the plants.
Avoid spraying your plants under full sunlight or bright indoor lights in order to prevent the liquid droplets from magnifying the light source and burning your plants. Also, the stomata are less dilated during the middle of the day in peak heat.
Make a Proper Nutrient Solution
Some nutrients give advice for how much to dilute their solution; others do not, so it is recommended you start low and work your way up. If your plants are young, use 20% of the recommended strength for liquid feeding per gallon. As the plants grow larger, you can increase the percentage while observing how your plants respond.
Protect your garden by first spraying one plant and see how it responds before you spray other plants that look ill. Note that the damaged leaves will not recover, but new growth will appear vibrant and strong, and aging leaves will appear more colorful.
Explore Nutrient Solutions
How to Foliar Spray Cannabis
A little goes a long way when it comes to foliar feeding, but precision is important. When you foliar feed your plants, you want to cover all the leaves. Do this by making a routine where you go from left to right or top to bottom. Plants do not need to be soaking to receive the nutrients.
Do you have any foliar feeding advice to share with other growers? Drop your tips, questions, or favorite products in the comments section below.