I believe that in order for me to make a decent first spray, I would want to emulate the contents of dry mass, or even the ratios of the contents. Being such a novice, it's difficult to fully understand if that data will be of use to me, let alone how to explain the validity of such a whim, but I feel like being able to see test results of high brix cannabis leaves will give me better insights to formulate one or more foliar sprays to try out.
I would suggest first learning how plants work. If we could improve a crop by simply spraying it with a nutrient solution based on leaf testing, every crop would be high brix, nutrient dense and perfect.
Foliar sprays CAN mitigate a limited deficiency. That's true. But they can't take bad soil and make it good.
But the way we use foliars in High Brix has nothing to do with deficiencies, but rather everything to do with revving up the soil life via root exudates. We test the soil in detail, not the plants. A refractometer is completely adequate to test whether something is working or not, but the answer to problems lies in the soil, not the leaves.
There are several fallacies on the webpage you linked:
1. They say use a wetting agent and suggest soap! Do NOT use a wetting/sticker/spreader.....especially soap. <------only a novice who copies and pastes info, not really understanding the science would say such a thing.
The spray must be quite acidic (hence no soap) if it is to penetrate the leaves. This changes the way the elements in the spray react with eachother. You can't just look at a leaf analysis and mix up the "missing nutrients" and spray it on. You must first understand which form the nutrients will be absorbed and what will happen if you acidify the nutrient solution....will new compounds form? Will the compounds you think will feed the plant ionize and link with another cation???
2. they say, "Don't spray during flower." Utter nonsense. This is prohibition mentality on display. The time the foliar benefits most is during bloom.
I'll close by quoting myself:
"""When the soil is dialed in and the microbes are happily chomping away at rocks and delivering them to the plant as food, the plant produces sugars and other compounds in the leaves and sends them down to the roots in the form of Root Exudates. The microbes crave these sweet exudates and will work day and night eating rocks for a sweet hit of that sugar! Even more, the plant customizes root exudates to actually communicate and signal the soil microbes to deliver certain types of nutrition. """
You'll come up against a big wall in your quest to use foliar sprays to increase brix in hydro: You've got no microbes to signal via root exudates! it's like having a keyboard but no computer.....type all you want, but nothing changes.
The other major issue with foliars in hydro is osmotic pressure. If you forgot to add nutes to your rez....and the plants started to yellow then an emergency foliar spray might help in the short term, until you got nutes in the rez.....
But if you're feeding high PPM salts and you further add salts to the leaves via foliar feeding.....now you've got a serious osmotic pressure problem. Crispy claws are the result.
Foliar sprays, generally speaking, are always used with soil.
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