Foliar feeding is possible due to the specific pores, found on the underside or on both sides of the plant’s leaf. These pores are called stomata, and their main duty is to enable gas exchange between plant and environment during the process of photosynthesis. Besides, respiration as well as water vaporization also occurs in stomata. Thanks to these tiny pores on the surface of the leaves, the plant can absorb water and nutrients dissolved in it.

However, because of certain barrier, only part of nutrient solution can be absorbed through leaves. So, foliar feeding can never be used as the only way to deliver nutrients to the plants. The primary task of foliar feeding or fertilization is to rapidly supply micro nutrients to the plants. Sometimes, using biuret-free urea one can deliver nitrogen via the plant’s leaves.

 Foliar Nutrient Application

In order to provide proper effectiveness of hydroponics nutrient sprays, it is necessary to keep in mind the rate at which plants absorb nutrients and translocate them within the plant. Besides, there are many other factors, which affect the uptake of nutrients within the plant. Some of them are indicated in the table at the bottom of this section.

Of course, it is not easy to consider all of those factors, but some of them are more important than others, so it is important to keep them in mind. First of all, when choosing a foliar fertilizer, choose the one with high quality wetting and sticking agent. It is necessary for ensuring proper adherence of droplets to the leaves, which in its turn will ensure effective absorption of fertilizing solution into the plant tissues.

 Though foliar feeding can be performed on a regular basis, there are certain periods, when plant fertilizing becomes especially important. For example, when the plants are in their active growing phase, or when fruits develop and plants need more nutrients than usual. Usually, during such periods plants gain additional ability to absorb nutrients through their leaves. Foliar feeding is especially beneficial for the plants with damaged root system, as it can partially compensate the decrease in nutrients absorption via roots.

The Role of Foliar Feeding in Hydroponic Gardening

In spite of the fact that hydroponic plants are meant to receive all the necessary hydroponic nutrients through the specially formulated nutrient solution, foliar feeding still provides additional benefits to them. It was proven by studies that those plants, receiving foliar feeding, provide more fruits in comparison to the plants without additional foliar fertilization. It has been shown that potato plants, treated with foliar fertilizers, provide better harvest with larger tubers. Weekly foliar feeding of tomatoes resulted in yield and fruit quality improvements. All the recorded improvements, provided by foliar feeding, allow treating this method not only as a quick fix of nutrient deficit, but also a reliable method to increase harvest.