There is no question that foliar feeding plants is an investment in time and resources. Is it worth it? Does it pay? The bottom line question we all need to answer is:
Why Foliar Spray?
There are many benefits to foliar feeding. In this article I will touch upon the main reasons why foliar feeding should be a part of your Standard Operating Procedure (SOP).
1) Foliar feeding is a toolbox full of tools.
Have you ever met a professional mechanic? A mechanic uses his or her understanding of engines and machines and combines that with physical effort to fix all sorts of problems.
Fixing an engine without tools doesn't work. Every mechanic has to have an array of tools. Each has a specific role it plays. As a grower you can look at specific foliar sprays as tools in the toolbox. They help you meet specific objectives in growing your crop.
2) Foliar feeding allows an additional supply of nutrients into the plant.
The primary supply of nutrients into the plant is through the roots. Yet the leaf is another route of entry that should not be discounted. Nutrients can penetrate the leaf via its stomata and directly through the cuticle on the upper part of the leaf.
Imagine your family budget where you consistently spend 110% of every month's income. Credit card bills and debt at local businesses keep climbing. In this context 10% makes a big difference. Now imagine you start a small family business and your income goes up 20% while your spending stays the same. Now you only spend 90% of your monthly income. Is this a significant change? Absolutely! Finances changed from great stress to great relief. Likewise the small addition of nutrients from foliar feeding can have a very significant impact on the "nutritional budget" of your plants.
3) Foliar feeding only uses small doses of nutrients but can have a large impact.
Small doses is a key parameter when foliar feeding. How much salt does it take to salt your food? Very miniscule compared to the amount of food. I remember when I first formulated a garden spray called BrixBlaster. It was designed to increase blossoms, flowers, and pod set. I used it on marigold flowers and green beans. I sprayed 2-3 times per week and the results were amazing.
The marigolds produced so many flower heads they were practically bumping into each other. On the green beans the results were very fast. I could spray in the afternoon and next morning see a profusion of tiny white blossoms. How much product was I using? Only ½ oz. in a quart of water and then only applying a light misting. This equates to 1-2 quarts per acre.
4) Foliar feeding directs crop physiology.
This is an extremely powerful aspect of foliar feeding. Farmers have used this many times to increase yield. Here is another rule from Wendell: A foliar spray is a command to the plant. A foliar spray can push a plant towards vegetative growth that results in more stalks, stems, and leaves. Or toward more reproductive energy that results in blossoms, flowers, and pod set.
The key is to use the right "command" at the right time according to the current stage of the plant. As an example if you are raising alfalfa for animal feed and the regrowth after a cutting is now 12" high it would be great to foliar spray a growth/vegetative spray such as:
2 quarts Amaze
1 quart PGR
4 oz. Boric Acid
2 lbs. Dextrose
20 gallons Water
Why spray this? To increase tonnage. What you should not do is to spray Bloomit (a strong reproductive foliar spray) on the alfalfa. Why? It can switch the plant from growing stalks, stems, and leaves and instead promote blossoms and flowers. When this happens tonnage is substantially reduced.
5) Foliar feeding helps correct trace mineral deficiencies.
This is one area where foliar sprays really shine. Since trace minerals are only needed in trace amounts a small addition can fix a big problem. Specific trace mineral sprays will be covered in other articles.
6) Foliar feeding improves the efficiency of the leaf.
The leaf is the plants' warehouse. Inputs come in, energy comes in, new products are made, and then the new compounds are shipped to other parts of the plant. Adequate mineral nutrition increases this process significantly.
7) Foliar feeding can increase quality.
Nowhere is this more evident than on fruit. A large crop of apples takes up less than 100 lbs. of calcium from the soil per acre. An apple with 300-500 ppm of calcium on a dry matter basis does not taste or store well. Even before it quickly rots it will be mealy and mushy. When calcium is at 1,200 ppm or higher the apple will be crisp and crunchy. It will keep in cold storage much longer and can even grade larger because its weight per size is higher. The same foliar spray used to increase vegetation in alfalfa can increase the solids in apples. Use a plant tissue test to determine if you need the boric acid. Amaze has the added benefit of supplying mobile calcium that is deposited into the apple. Mobility comes from being hooked to the phosphate.
8) Foliar feeding can increase yield.
This is the big one for farmers. If it doesn't pay to spray then why spray? Foliar feeding that increases yield happens in two primary ways. Either the foliar spray provides more minerals needed by the plants or the nutrients enhance the plants' resistance to disease or fungal attack. In the first situation the increase of minerals help further plant metabolism via enzymatic reactions thus increasing yield. In the second scenario yield is being lost because the plants are expending so much energy fighting disease or infection. When nutritional foliar sprays enhance plant health more energy is available to increase crop yield.
The last point brings up another rule to keep in mind. Use nutrition as the first defense against insect and disease pressure.
Foliar sprays can help you do this two ways: 1) Proactively as part of a regular spray program, and 2) Reactively in critical situations.
The first is better but the second is still useful.
There you have it; eight reasons to consider why foliar nutritional sprays can benefit your operation.