Foliar feeding of cannabis plants

Foliar feeding of cannabis plants

Cannabis, like all other plants, gets its energy from a process called photosynthesis. In this process, several different ingredients are mixed together in the leaves to produce energy from light.

These ingredients come in liquid and gaseous forms and their intake or outlet is regulated in an almost similar as to the way as the skin on our human bodies can absorb moisture through the pores.

The plant's pores, or better yet the leaves' pores, are called stomata. They are little openings that are encircled by two guard cells and together they can help the plant absorb nutrients, CO2 and release oxygen.

Spraying the stomata with nutrients can help the plant mitigate stress due to nutritional problems; the fertilisers that are sprayed on instead of being mixed into the soil are usually three to five times more efficient and they can make elements like iron and phosphorous, that do not translocate, easily accessible to the plant.

It also saves the plant energy and time because the nutrients will not have to travel all the way from the soil, up the stem and into the leaves. You spray the nutrients right where and when they are needed. Basically, foliar feeding is an extremely fast and effective way to correct your plant's nutritional problems.

Foliar feeding is a cloner's best friend. When cloning you take cuttings from a mother plant that, at least in the beginning, does not yet have a fully developed root system of their own.

Reaching the much-needed nutrients and minerals can be very hard for young clones, also for regular seedlings though. When foliar-fed, the nutrients can easily and quickly be used by the plant to help it grow its own root system quicker and starts its vegetative cycle.

Make sure to watch carefully for any discolouring on the young plants and if found spray them with a heavily diluted mixture of fertiliser and water.

Although it does provide an extra boost to the growth of your cannabis plants, foliar feeding could never and should not replace a standard fertilising regimen that is focused on the root system.

If balanced correctly the combination of the two should produce bigger, better and heavier yields when harvested.


Mist style sprayers are the best for foliar feeding because the small particles will be easier for your plant to absorb and they make misting the entirety of the plants an easy task.

The smaller droplets also evaporate quicker and easier making sure the plants get their dry time in between misting and fungus buildups are less easily formed. Spray the leaves until they are evenly covered and do not forget to also cover the underside of the leaves to make sure they get the maximum amount of nutrients possible.

Liquid fertilisers are the best choice for foliar feeding, especially fertilisers that have been designed to be used in hydroponic systems but fertilisers for soil work great as well.

If you can find a liquid fertiliser that has trace elements or micronutrients in them, those are even better. Do keep in mind though that most fertilisers should be diluted to around 50% of its original strength because too many nutrients can cause your leaves to burn and curl up. This might be more harmful than helpful and can really hurt your plants or stunt its growth.

To make sure the solution you are spraying on your plants isn’t too concentrated try it on a few leaves first. Carefully monitor the sprayed leaves and watch for discolorations, if you see any damage to the plant spray the leaves with only water and try again in a few days with the mix diluted down to another 50% (effectively 25% of its original strength).


The best time to do your foliar feeding is early in your plants light cycle, if grown inside, or at the beginning of the day when grown outdoors. This is because the stomata are opened when they sense light and to ensure that the plant has a chance to completely dry up before being misted again.

Please keep in mind that in hotter climates, temperatures of around 27 degrees Celsius or hotter, the stomata will start to close to protect the plant from the heat so try to mist your plants in the cooler mornings when the stomata are still open.

Another reason not to mist midday is that the sun could use the droplets as a magnifying glass and burn holes into the leaves.

When the cannabis plants go into their flowering stage it is recommended that you stop the foliar feeding. The mist could have nutrients build up in the buds and yield a harsh tasting harvest because the residue has not had time to be washed off or has mixed with the resin.

It could also be harder to completely dry for your plants and you risk your buds rotting or fungus being built up in your grow room.