Cannabis Cultivation

How to Maximize Plant Health, Foliar Feeding Cannabis

Foliar Feeding Cannabis

Cannabis Growers have been using foliar feeding techniques for many years to help their cannabis plants grow stronger and healthier. Used correctly, foliar feeding cannabis can create larger cannabis plants, bigger stocks, and larger and more dense cannabis buds. 

Cannabis plants are able to absorb nutrients and plant hormones through their leaves.   This is very effective if you are having nutrient deficiencies as the plant will not have to find these nutrients in its rootzone. In this article we will teach you how to grow cannabis using foliar feeding techniques that we use to grow the best and most healthy cannabis.

Spray Bottle For Foliar Feeding Cannabis
Spray Bottle for Cannabis Foliar Feeding

What is Foliar Feeding Cannabis?

Foliar feeding is a way to fertilize cannabis plants using water and nutrients mixed together and sprayed on your cannabis plants. Cannabis growers will take a nutrient source that dissolves in water, then they will take and fill a good spray bottle and spray this nutrient solution all over their plants. 

They will make sure to spray the entire plant, getting both the tops and bottoms of the leaves with a good soaking.

How Does Foliar Feeding Work?

Typically a cannabis plant will take in nutrients through their roots. They will be brought up into the plant to be used by the plant tissues to grow healthy. Cannabis can also take in nutrients through their leaves. 

When a grower sprays a water nutrient solution on the plant it will absorb the water and nutrients through the stomata. The stomata are tiny holes under the plants leaves, you can’t see them with your eyes because they are very small. The stomata on the bottom of the leaves can only be seen with a microscope.

These tiny holes open and close as the plant gets warmer and cooler, during a typical day night cycle. They tend to open more in hotter weather to cool themselves, and take in CO2 from the air around the plant. The stomata also open take in water, when this happens if the water from foliar feeding contains nutrients they will also be taken into the plant. 

Spraying a Cannabis Plant With Foliar Feed
Spraying a Cannabis Plant with Foliar Feed

What is the Advantage of Foliar Feeding?

As nutrients are taken in from the leaves instead of through the roots, the plant is able to absorb them much quicker and easier than if they were brought up from the plants root system. The advantage of this is that the plant can take in nutrients that it needs quickly, and growers can fix nutrient deficiencies using foliar feeding much faster then using a water and nutrient soil drench. 

Is Foliar Feeding Effective for Cannabis?

Like with most vegetative, leaf based plants, foliar feeding is very useful and beneficial for cannabis plants. It can be very helpful if you are experiencing nutrient deficiency issues with your plant. It is very effective for quickly fixing these issues.

What do you need for Foliar Feeding Plants?

There are only three things that a cannabis grower needs in order to feed their cannabis plant using this method.

  • A quality Spray Bottle 
  • A quality Water Source, distilled works best
  • A nutrient that is soluble in water, either organic or salt based 

Foliar Feeding Frequency

Growers can feed cannabis as little or as much as they like. Some growers will foliar feed several times a day while others may only foliar feed a couple times a week. We recommend doing it at least once a day. 

Doing so will help keep your plants very healthy and green. Grower should remember that this isn’t a replacement for waters and nutrients feeding your plants with the root system. Foliar feeding is a supplement to your normal way of growing quality cannabis.

Ways to Foliar Feed Cannabis Plants

Since the stomata are located under the leaves of the plant it makes perfect sense to spray the plants with the nutrient water under the leaves. Growers can also spray the top of the leaves as well however it will have less effect. Make sure to drench the underside of all the plant leaves very well, some leaves may be blocked by other leaves so be sure to move them around as you spray the plant down. 

The plants should be dripping water once you have finished your feeding.

Types of Things you can use to Foliar Feed Cannabis

The first thing you will need is water, spraying a plant with just water can go a long way to keep your plant healthier. The water will wash away dust and dirt from the leaves, allowing them to better absorb CO2 and dispel oxygen from their leaves. 

You can add a soluble nutrient to the water as well. There are some bottled nutrients that are created specifically for foliar feeding cannabis and other plants. 

Growers can also make their own foliar feed for their plants. We can recommend some different things to use, but one of our favorites is soluble seaweed. This can be mixed with water and sprayed on your plant leaves. Seaweed is a great foliar feed as it contains many nutrients and growth hormones to help your plant stay healthy and grow well.  

You can also use types of organic nutrient teas, once the grower has brewed these teas they can also be applied directly to the plant or mixed with a ratio of water. 

Growers will also use salt based nutrients as a foliar spray, most of these bottled nutrients will come with instructions on how to apply as a foliar nutrient mixture.

Can you Foliar Feed Cannabis During Flowering

You can foliar feed cannabis during flowering, however only for the first two weeks after the lights have switched to 12 hours of darkness to start the flowering process. It is advisable to stop foliar feeding after this time. Spraying any type of water based substance on your flowering plants is a bad idea. It can raise the humidity around and inside the buds. 

This will cause mold and mildew issues in your flowering buds. You want to avoid this as much as possible.

Best Time to Foliar Feed Cannabis

There are better times to foliar feed cannabis than others, and there are certain times that growers should not feed their cannabis plants this way. 

We recommend using a foliar feeding application about an hour before the lights are about to turn off in your grow room. Another good time to do this is when the lights come on.   

There are times when you should not foliar feed your plants, when the plants get over 75F or when your lights have been on for awhile. The plant’s stomata start to open very wide when the plant gets hot. This is because the plant does this to start to cool off. If the plant has any water on it, this can burn the plants so it should be avoided. 

Never foliar feed cannabis outdoors when it is in the midday sun. The plant is in the full heat of the day, and it can burn the plant quite bad if you do this.

Foliar Fed Cannabis Plant
Foliar Fed Cannabis Plant

Foliar Feeding Recipes for Cannabis

There are many different types of foliar feed you can use for your plants. Here are some recipes that we like to use on our plants. 

  • Dissolve Kelp (seaweed) in Water, add a bit of Organic Calmag 
  • Dissolve Kelp (seaweed) in Water, add some dissolved Epsom Salts

Remember that any salt based bottled nutrient can be used as a foliar feed for cannabis.

Can you Foliar Feed or Spray Too Much?

You can foliar spray too much if you are doing it at the wrong times as stated earlier in the article. However other than that there is no real way to foliar spray cannabis too much. If you are having a serious nutrient deficiency while your plants are working to correct that, spraying more times can help to fix the issue more quickly.   

Since plants can take in nutrients far better this way, it is a great way to fix your plants and get them back on track as quickly as you can. It is very beneficial so there is not really a way to do it too much.

When is Foliar Feeding Cannabis not Good?

Growers can feed salts on their leaves which is not good for cannabis in large amounts. If you are using a salt based foliar feed on your cannabis, the salts can build up on the leaves of the plants. When this happens you are at risk of burning your plants. 

If you are using a salt based nutrient for foliar feeding it is advised to use plain water for every other foliar feeding this will help the plants continue to use the salt nutrients that were left behind from the last feeding, and to wash off any excessive salts that were left behind on the leaves of the plant.


As long time growers we very much recommend using a foliar feeding cannabis plan with your grow to maximize the growth production of the plant. Foliar feeding can help to clear up minor plant issues quickly, keeping your plant healthy and growing to their maximum potential throughout the growing season or period indoors. 

We also recommend using organic tea for foliar feeding. You can read how to make an awesome Alfalfa Tea for foliar feeding cannabis here.

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