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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

Get more tips and advice on how to troubleshoot common marijuana pest issues from the experts at Leafly.

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.

What Is Nutrient Lockout and How Does It Affect Cannabis?

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.

Stages of the marijuana plant growth cycle

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.

What are the best nutrients for growing cannabis?

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.

Lead image by mediaphotos/iStock

Trevor Hennings's Bio Image
Trevor Hennings

Trevor is a freelance writer and photographer. He has spent years in California working in the cannabis industry.

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