Pioneering Hydroponics

Since 1976

What is Foliar Feeding?

Hydroponic nutrients can be used in foliar feeding in spray form. Instead of adding fertiliser to the growing medium, you simply spray it onto the plants’ leaves. This lets nutrients pass directly into the plants’ vascular system by direct leaf and stem absorption.

What is Foliar Feeding?

Simply put, it’s a great way to address nutrient deficiencies. Particularly if your hydroponic grow system has multiple plants but only a select few show deficiency signs. It allows you to treat these plants without compromising the entire system’s feeding schedule - or leading to the other plants becoming unbalanced.

If you’re growing with soil, you shouldn’t use foliar feeding as an alternative to good, healthy soil. Plants need major nutrients such as phosphorus, nitrogen, and potassium in big quantities, which they wouldn’t be able to get just through their leaves.

For micronutrients like iron and zinc, foliar feeding ensures that plants have what they need to grow strong and healthy. In addition to addressing nutrient deficiencies, this is also a great way of giving your plants a boost if they’re under stress either from pests or diseases.

How Does Foliar Feeding Work?

When liquid fertilisers are sprayed onto leaves and stems, plants absorb the nutrients through their epidermis or through the stomata. The epidermis is the outer layers of plants’ cells and the stomata are the pores found mainly on leaves’ undersides. 

The stomata regulate gaseous exchanges and water content, and nutrients are absorbed much faster through them.

What are the Benefits of Foliar Feeding?

  • Corrective nutrition. A fast and effective way of treating nutrient deficiencies, as foliar uptake is much faster than the root uptake of nutrients.

  • Boosting growth. The precise timing of foliar feeding can help improve yield and growth, by directly applying nutrition during these critical stages in which plants have low concentrations of much-needed nutrients.

  • Complementary nutrition. Should plant growth be stunted due to stress, pests, or diseases, plants will benefit from foliar feeding providing complementary nutrition.

  • Efficiency. Helps to activate specific plant mechanisms, such as stimulating flowering.

There are, however, a few factors in you need to keep in mind if you’re seriously considering foliar feeding. It’s very easy to overfeed plants, as foliar feeds inject nutrients straight into plants. Phytotoxicity is a real concern and your plants will likely show signs of nutrient burn with yellow, crispy, and dry tips on the leaves.

Nitrogen toxicity is another possibility, with new leaves darkening and growth becoming misshapen or distorted. This happens due to plants trying to grow faster than they can cope with. 

How to Foliar Feed

When foliar feeding, you need to make sure you don’t make the spray too strong as it can scorch the leaves due to high salt concentration. Spray a few leaves to test the strength of the spray before moving forward to the rest of the plants. Make sure to dilute the spray if the test leaves show any signs of scorching.

Foliar feed only when your grow system’s lights are off. Liquid drops can often act as lenses that hurt plants instead of helping them. Additionally, when plants have to feed on light and absorb nutrients at the same time, they might choke. 

Spray plants on both sides of the leaves. Plants can absorb nutrients through both sides of their leaves, and foliar feeding on both sides of the leaves makes absorption much faster.

Make sure to spray with a fine mist. This gives plants a thin layer of nutrients instead of over-saturating your crops.

We recommend:

House & Garden Magic Green Foliar

Humboldt Honey Hydro

If you want to know more about hydroponic nutrients, make sure to get in touch with our friendly team by giving us a call on 01695 554 080 or 01226 320 850. You can also find a shop or become a stockist of some of the UK’s leading brands in hydroponics.