Foliar Feeding with Results

March 6, 2023

Foliar feeding is known as a fast way to get nutrients into plants, and is one of the most effective ways to improve brix content during the season – if done correctly.

To get the results you are looking for, you need some foundations addressed from a soils perspective, which we talked about several weeks ago. Specifically, it helps if cover crops are used, compacted soil is subsoiled, calcium to magnesium ratios are addressed, and carbon and nitrogen is balanced.

But what if you have already addressed those? What else does it take to formulate a good foliar spray?

First is good water. Water quality has a big impact on how foliar applications will respond. It is so pronounced that we recommend testing your water and using only if below 5 grains of hardness, or 85 ppm. If above that, we recommend using reverse osmosis or rain water. Both typically work equally well. Rain water is typically the most cost effective, but is sometimes not practical from a regulatory perspective.

Second is knowing what to apply. Testing is obviously recommended whenever practical because how else can you know what they need? But there are also some nutrients that are more important to address than others. We look at two things: key photosynthesis minerals and also critical points of influence.

From a standpoint of photosynthesis minerals, there is not an exact sequence. The following could serve as a checklist of minerals that are extremely important:

• Calcium is first because it is considered the trucker of all minerals, and when it is in adequate supply, it is easier to get other nutrients into plants, especially if phosphorus is also adequate.
• Nitrogen is critical because without it, plants have no chlorophyll or green pigment. There are four atoms of nitrogen in the chlorophyll molecule.
• Magnesium is also part of the chlorophyll molecule, helps nitrogen metabolism, and greens plants.
• Iron and manganese are both needed in small amounts but are critical for photosynthesis.
• Silica – we have seen higher brix using silica. Silica helps nutrient uptake. According to Hugh Lovel, boron makes silica thirsty for water and nutrients, so boron is also important.
• Potassium is also needed, we want it higher than nitrogen, or you will not get high brix.

Tank Mixing Order: The tank mixing sequence also makes a difference. Start by filling the tank with water to about 90% of capacity. Next we put in any nutrients we want to add, then seaweeds and other plant stimulates. Next we put in any microbial inoculants desired. Finally, we add any spreader stickers if needed, then fill up the rest of the tank with water.

Electrical Conductivity: Once you’ve decided what to apply, you need to figure out how much of each. For crops that are being foliar fed on a regular basis, we want to the electrical conductivity to be no higher than 3.00 as measured on an EC meter. This EC reading is very important and we recommend that you check this before applying the foliar. Remember, more is not always better.

Timing: Foliar applications are most effective when applied in late evening or very early morning.

In summary, foliar applications can be ineffective or very effective, depending on how they are formulated. It is well worth the effort to make each application effective.