"Lets take a closer look at what happens when a foliar spray is applied to plant leaves. A well-made foliar spray is a dilute nutrient solution. If properly constructed it will pas through the leaf surface and increase the photosynthetic capability of the plant. In other words it will allow the plant to take in more energy from the sun. The difficulty is in properly constructing the foliar spray."
Now that's interesting. I got the most damage in the leaves that were closest to the light - kinda puzzled me. I'm used to seeing N def in the older, lower leaves. So I boosted photosynthesis with the foliars, and then starved the soil with the cat switch - fastest leaves yellowed first.
Clear thinking like that will take you very, very far. N, being a mobile element, will always show deficiency in the lower leaves first. Too many people, when they see yellow think N. "Clever" folks will think Zinc or Sulfur....since the leaves are on top. However, there isn't a deficiency of anything.....the soil is just screwed up. Adding stuff will only make it worse, with the exception of Humic Acid and Calcium Nitrate. Humic acid will help "bust out" the clingy cations, as will the Ca++. The nitrate will feed the plants until things get sorted out.
That is exactly what happened, although it would have happened even if you didn't foliar feed.
Foliar sprays are not for the plant, per se.....they're for the biota in the soil, specifically attached to the roots.
Before I was doing high brix, I'd add this, or that.....try this tea, that tea......I'd see some results, over time. Things were green, leaves were healthy, taste was great....super cool.
Then, when doing actual, laboratory designed high brix soil, drenches and sprays.....WOW. What a difference a day makes! Each spray, each drench....you can see results almost overnight. That's because the soil is balanced, the biology is active, and we're feeding the plant according to a much more scientific and current methodology.
Mineralized Soil, major elements in proper balance
Trace elements in the proper ratio
Hyperactive soil biota
Foliar spraying designed to feed the biota
That's high brix. We often get confused trying to apply NPK or hydro thinking to the program. Neither applies.
Let the critters in the soil do their work. They do a much better job than we can.