Learning How To Foliar Feed Cannabis

If you're looking for ways to achieve healthier, more robust plants, it's time to consider foliar feeding. This technique isn't just for the pros—anyone can master it with the right knowledge. 

Foliar feeding can provide your plants with essential nutrients and protection directly through their leaves, which allows faster absorption and quicker results.

In common practice, fertilizers go directly into the soil for the roots to handle absorption. However, with foliar feeding (or foliar sprays), you can apply liquid fertilizers to the leaves of the cannabis plants to potentially increase the yield significantly.

In this article, we will break down why and how you should use them.

Quick Tips

• Foliar feeding can give your cannabis plants a quick nutrient boost.
• Different recipes serve different purposes, from growth to pest control.
• Timing is key: apply at the right stage and time of day.
• Avoid overdoing it to prevent leaf burn or mold.
• You can shop the best nutrients and growth supplies from our collection.

What’s foliar feeding?

Foliar feeding is a technique where you’re essentially spraying liquid fertilizer directly onto the leaves of your plants. Instead of the roots doing all the work, the leaves get to soak up those nutrients fast.

Why Bother?

1. Quick Fix: Leaves absorb nutrients faster than roots. So, if your plants are showing signs of deficiencies, foliar feeding can give them a quick pick-me-up.
2. Healthy Plants: It helps fix nutrient issues faster, so your plants stay healthy and green.
3. Better Growth: Direct nutrient application can speed up growth. However, foliar feeding can be used as a supplemental treatment, but you’ll still need to continue feeding the rhizosphere.

A bit about the science behind Foliar Spray.

When you spray nutrients on the leaves, they enter the plant through tiny openings called stomata. When plants receive this foliar spray, their stomata can also absorb the nutrients, and they travel through the plant’s vascular system. 

It’s a more direct route than the roots-to-shoots path.

Foliar feeding is particularly effective for delivering micronutrients like iron, manganese, and zinc. 

You’ll only need them in small amounts, but they’re crucial for plant health. Remember that foliar feeding solutions also need to be pH adjusted before spraying them directly onto the leaves. 

Ideal conditions for foliar feeding

Foliar feeding works best when conditions are optimal. Here’s what you need to keep in mind:

1. Humidity: High humidity (83% to 87%) can help keep the stomata open, improving nutrient absorption.
2. Temperature: Avoid foliar feeding when it’s too hot (the ideal temperature should be about 70F / 21 °C), as this can cause the solution to evaporate before the leaves can absorb it.
3. Time of Day: Early morning or late evening is best. This helps avoid the midday sun, which can cause the spray to burn the leaves.

These are conditions you can’t control when you’re growing cannabis outdoors. 

Types of Foliar Sprays

We can put foliar sprays into 2 major groups: 

Sprays that are used to treat problems located on the surface of the leaf. For example, pesticides can be used for surface fungi like mildew. 

And then you have systemic sprays that are absorbed into the plant before they’re transported to where they’re needed—through the vascular system.

These are the three most common types of foliar sprays you can use today, depending on what your plants need:

1. Nutrient Sprays: These are packed with essential nutrients that your plants might lack.
2. Pest Control Sprays: Some sprays are designed to deter or kill pests. Neem oil is a popular choice but can only be used during the vegetative stage.
3. Growth Enhancers: These sprays contain hormones or other compounds that promote faster growth.

Common Ingredients in Foliar Sprays

What’s in these sprays? Well, here are some common ingredients you might find:

• Epsom Salts: Provides magnesium and sulfur, which are essential for photosynthesis and overall plant health.
• Seaweed Extract: Rich in trace minerals and growth hormones, it boosts plant vitality.
• Molasses: Adds carbohydrates to feed beneficial microbes in the soil.
• Neem Oil: Works as a natural pesticide and fungicide.
• Compost Tea: A nutrient-rich brew that enhances microbial activity and nutrient availability.

Should You Foliar Feed Your Cannabis?

When and Why?

Foliar feeding is beneficial, but you gotta know when and why to use it. To give you all the perspectives, here are the pros and cons:

When to Use a Cannabis Foliar Spray

Now, don’t go overboard. Timing is everything. When should you go for it? Check this out.

For the vegetative stage, once a week is usually sufficient.

Be cautious during the flowering stage. We would advise against spraying anything on your plants during flowering.

Best Times to Apply Foliar Sprays

How to Foliar Spray Cannabis

Convinced foliar feeding is worth a shot? If you need help figuring out exactly how to use foliar sprays—what equipment to put together, what quantities to use, etc. This is the guide for you.

Step-by-Step Guide to Using Foliar Sprays for Cannabis

Before you start, get your tools ready and set the right conditions.

Tools needed: You’ll need a pump sprayer (commonly available in one to three gallons) which has a flexible hose connected to the handle so you can get under the leaves. In addition, you’ll need a pH meter, measuring spoons, distilled water, and your chosen nutrient products.

Ideal Conditions: Aim to spray in the early morning or late evening. This helps avoid leaf burn from sunlight and ensures the stomata are open for better absorption.

Let's get spraying! 

Mixing the Solution

1. Using your measuring spoons, add the required amount of nutrients to your pump sprayer. A common recipe is 1 gallon of distilled water with 1 teaspoon of Epsom salts, 1 teaspoon of seaweed extract, and 1 teaspoon of molasses.
2. Adjust the pH: This is crucial. Use your pH meter to ensure the solution is between 5.8 and 6.2. If it’s off, use pH up or down products to adjust it.

Spraying the Plants

1. Spray Evenly: Hold the spray bottle about 6-8 inches away from the plant. Spray the leaves evenly, making sure to cover both the top and undersides. The undersides have more stomata and can absorb nutrients more efficiently.
2. Avoid Dripping: You want a fine mist, not dripping leaves. Dripping means you’ve overdone it and it can lead to nutrient waste and potential burn. You can also use a wetting agent like Coco-wet to help optimize coverage and absorption.
3. Watch and Wait: After spraying, observe your plants over the next 24-48 hours. Look for any signs of nutrient burn or improvement in plant health.

Tips and Tricks for Foliar Spraying Cannabis

First the few common mistakes, and then some best practices we’ve found helpful.

Common Mistakes and How to Avoid Them

1. Don’t spray in direct sunlight: The intense light can cause the spray to burn the leaves. It is much better to spray in the early morning or late evening when the sun isn’t too strong.
2. Monitor pH levels: Ensure the spray solution has the correct pH to avoid nutrient lockout. You can regularly check the pH before spraying.
3. Alkaline water: If you’ve got a powdery mildew problem, alkaline water can also help. 
4. Start with lower concentrations: If you’re new to foliar feeding, start with a more diluted solution of your choice spray product combined with a wetting agent like Coco-wet. You can always increase the concentration if needed.

Best Practices for Effective Foliar Feeding

1. Use Distilled or RO (Reversed Osmosis) Water: We know that tap water can contain impurities like chlorine, which might harm your plants. Distilled and RO waters are pure and ensure that your plant’s nutritional solution is clean.
2. Spray Thoroughly: As you spray, make sure you cover all the leaves, including the undersides. This ensures that all parts of the plant can absorb the nutrients.
3. Frequency: Stick to a schedule. Foliar feed once a week during the vegetative stage. In the flowering stage, be more cautious. Early flowering is okay, but avoid spraying during the later stages to prevent mold and mildew.

Homemade Foliar Spray Recipes

Why not make your own? 

It’s cheaper and you know exactly what’s going into it. Now, we recommend you only do this if you have some experience; otherwise, you might be better off shopping for these sprays.

The Best Foliar Spray Recipe

Ingredients

• 1 gallon distilled water
• 1 teaspoon Epsom salts
• 1 teaspoon seaweed extract
• 1 teaspoon molasses

How to Mix It

1. Combine Ingredients: Mix everything in a spray bottle.
2. Adjust the pH: Make sure it’s between 5.8 and 6.2.
3. Spray Away: Apply the solution evenly to the leaves.

Top foliar spray recipes and their perks

Is foliar feeding effective for cannabis?

Science and Stories

Research and growers alike vouch for foliar feeding. Studies show nutrients can be absorbed faster through leaves than roots, making it a go-to for quick fixes.

Effectiveness Based on Nutrients and Sprays

Can You Foliar Spray During Flowering?

The right answer boils down to the risks and rewards. 

Foliar spraying during flowering can be tricky. There might be residue left on the buds that can react when exposed to heat while smoking. The residue can have dangerous effects when combusted.

In addition, there is also a worry that mold can develop. Avoid spraying during flowering and only spray during the vegetative stage. 

Foliar Spray pH and Runoff PPM

Why pH Matters

Keeping the right pH in your foliar spray is critical. If the pH is off, your plants can’t absorb the nutrients properly. The ideal pH range for foliar sprays is typically between 5.5 and 7.0.

Checking Runoff PPM

Monitoring runoff PPM (parts per million) ensures your plants are getting just the right amount of nutrients.

Common Issues with Foliar Feeding

There are a few potential issues you should look out for when implementing foliar feeding.

Potential downsides and how to mitigate them

1. Foliar Burn: This happens when you spray during high heat or use a solution that’s too concentrated. Always spray in the early morning or late evening and start with a diluted solution.
2. Mold and Mildew: High humidity combined with foliar feeding can create a perfect environment for mold. Ensure good air circulation around your plants and avoid oversaturating them.
3. Nutrient Lockout: If your spray has the wrong pH, it can prevent your plants from absorbing other essential nutrients. Always check and adjust the pH of your solution.

Wrapping Up

There you have it—a complete guide to foliar feeding your cannabis plants. It might seem like a lot at first, but once you get the hang of it, foliar spraying can be a quick and efficient way to boost your plant’s health and growth. 

Why not start with high-quality seeds that give you the best foundation for thriving plants? Check out our extensive collection of cannabis seeds and strains at Homegrown Cannabis Co.