Speaker (John Kempf) explains why ‘rebound boron’ products exist and when to use them. Ionic/soluble boron (e.g., boric acid, Solubor) applied to leaves is not phloem-mobile and will not move from leaves into fruit or roots; therefore the preferred, cheapest way to correct boron deficiency is soil-applied (pre-plant or broadcast) or via root-applied soluble boron through irrigation. Rebound boron is a complexed form (anion complex, not a cation chelate) that allows foliar-applied boron to be transported within the plant to fruit or roots during the growing season, improving calcium–boron interactions, fruit firmness, sugar allocation, storability, and sometimes root microbiome/pathogen outcomes. Practical advice: use rebound boron when mid-season foliar correction is needed or when targeting fruit quality or root microbiome effects.
Chapters
Why does rebound boron exist if you can go out and buy Solubor? There's a reason and there's a parallel reason to why we don't have a rebound magnesium. We are specifically only creating products for which there's a very clear need based on what's happening in the field and based on plant physiology. So let's talk about boron for a little bit. So boron within the plant is not flow immobile, which means that we can't put on a foliar application of soluble, of ionic boron, whether it's soluble boric acid, whatever form it might be on the leaf surface and expect it to move from the leaf. Let's say we have some fruit, we cannot put on a boron application of soluble here on the leaf and expect it to move into the fruit in the ionic boron form. Or if we're growing a root crop like potatoes or beets or carrots, we can't put on a foliar application of boron on the leaf and expect it to get down into roots are into the tubers. And that is because boron cannot be transported from the leaf down as long as it is in the ionic boron form. So the reality is the, the least expensive way to address boron, what is best for the grower, what's best for the crop, is to put on a slow application of boron so that we get it in the root system either at planting, pre planting or rebroadcast on the soil. That's the cheapest and most effective form of boron. But if you don't have enough boron and you're in the middle of the growing season and you need to get boron into, because of course boron has this synergistic relationship with calcium to form strong cell membranes. If we want to have fruit that has exceptional shelf life and storability, we don't have calcium related disorders like blossom end rot, cell wall rot and so forth, sun scald. We have to get calcium into the fruit in association with boron. And boron is also very necessary and very foundational for producing high sugar content fruit. Because in many ways boron is kind of the switching agent that determines where sugar goes in the plant. So potassium is the major carbohydrate transporter that transports sugars out of the leaves into the fruit and into the root system. But boron to a large degree determines where the sugar goes and how efficiently it moves. So being able to get high levels of boron into fruit is one of the shortcuts for producing exceptional quality fruit, both in terms of fruit firmness and integrity, and also sweetness and carbohydrate content. So this is true whether we're growing cotton or grains or fruit and vegetable crops. The same foundational principle applies. So now, if you're in the middle of the growing season and you have a crop that doesn't have enough boron, if there is a mechanism and a means for applying boron through the root system with an irrigation system or cypress application, then we can do that again with a soluble application. We can apply that to the soil and it moves through xylem transport from the root system upward into the plant into the fruit. That can work very well. If we are looking at foliar applications, we need to have a boron. That is the technically correct term is complex. It's similar to a chelate. But a chelate technically only refers to a cation, to a positively charged ion. In the case of boron being an anion, negatively charged, we refer to it as a complex. So boron needs to be complexed such that it can land on the leaf surface and then be transported by the plant from the leaf into the fruit or into the root system or wherever it's required. And that's the reason for the existence of rebound boron is because we can put a boron application on in the middle of the growing season and have an immediate positive impact on the quality of fruit, seeds, grains. And in some cases where we have pathogens in the root system, we can change the way the microbiome is expressing itself by having more sugars transported to the root system. And that is again, a function of boron availability and boron supply to transport sugars from the transport sugars efficiently from the vegetation down to the root system. So there's a surprising number of instances where we actually put on foliar applications of rebound boron and manganese to address possible pathogens in the root system, because we put those products on up here and they can be transported down to the root system, which doesn't happen if you're using soluble or manganese sulfate or less expensive manganese chelates. So that's the reason for the existence of rebound born and where and how you should be using it.
