Plants take up most of their nutrient requirements through their roots, but plants can also absorb nutrients very efficiently through their leaves. So foliar feeding is a great way to supplement any nutrient program. It’s best to supply the majority of plant nutrients through the roots, especially the heavy-hitters such as nitrogen, phosphorus and potassium. Plants can absorb NPK through the leaves, too, but not in the amounts necessary for optimal growth. High concentrations of fertilizer salts in foliar sprays can easily burn the tender leaf tissues. So if you use NPK fertilizers as a foliar feed, use them sparingly… just enough to correct any temporary nutrient deficiencies. One exception: don’t use nitrate fertilizers as a foliar spray! Nitrate-nitrogen can break down into nitrites, which can be toxic to humans. So if you must use a nitrogen supplement on the leaves, make sure it’s in the form of an ammonium compound, such as ammonium-phosphate or ammonium-sulfate.
Foliar feeds are particularly useful for providing beneficial trace elements. For example, if the pH of the nutrient solution in the root zone rises above 7.5, many essential trace elements start to become unavailable to the plants, especially the metal ions. Under alkaline conditions, plants can quickly develop deficiencies in iron, copper, manganese and zinc, even if they are provided in the nutrient formula. But if you apply a light foliar spray which includes the deficient minerals, the plants can readily absorb them and quickly correct the problem. The same holds true with magnesium deficiency. A light misting with magnesium sulfate (Epsom salts) can green up magnesium-deficient yellow leaves in just a couple of days!
Yucca extracts will improve the performance of any foliar spray. Water tends to bead up on waxy leaf surfaces, but yucca extracts are a natural “surfactant”. In other words, yucca breaks the surface tension of water molecules and allows them to spread out evenly on the surface of leaves. The more surface area the foliar spray covers, the better the absorption by the leaves. Yucca is also known as a spreader/sticker, allowing the foliar sprays to remain in contact with the leaf surface longer. So it will work well with either nutrient sprays or insecticidal sprays. It’s best to apply nutrient foliar sprays early in the morning, so the plant will have time to absorb the nutrients throughout the day. On the other hand, any of the contact insecticides are best applied towards the end of the day. Insects are generally more active during warmer temperatures, so the sprays have a better chance to do their work. Just don’t use any foliar sprays in the heat of the day. It could quickly concentrate, and possibly burn the leaves!
Yucca extracts also work very well when used in conjunction with other organic supplements. Try adding yucca extracts the next time you apply organic bio-stimulants such as amino acids, kelp, humic acid or compost teas. Soluble kelp extracts and humic/fulvic acids contain over 60 beneficial trace elements and a storehouse of micronutrients. Combined with the nutrient-absorbing compounds in yucca, the benefits of the organic bio-stimulants are amplified, providing a downstream effect on the color, flavor and nutritional value of food.
Harley N. Smith
RAW Soluble Powdered Yucca
available from Easy Grow Wholesale.
For pricing and further information please call
+44 01472 346 900