Examine the Essentials: Boron
Boron is anything but boring. It’s a multi-functional micronutrient that aids in cell division and is a component of cell walls. It helps manage water in plants by regulating the opening and closing of stomata, and helps balance the rations of sugars and starches in a plant. Boron takes on added importance during the reproductive phase of a plant, as it is a key requirement for the production of pollen tubes. No boron, no pollen. No pollen, no seed or fruit formation.
Boron is typically available in sufficient quantities in soil. However, high pH (alkaline) soil reduces the availability of boron to plants. And the element easily bonds to sugar molecules, though, so it doesn’t move around the plant once it is inside. Symptoms of boron deficiency are poor flower and fruit development or withering leaf tips. If your strawberries are small and lumpy, it could be a sign of boron deficiency. Other hollow fruits like watermelons or zucchini may be caused by a boron deficiency that prevented proper reproduction activity. Apples, beets, turnips, broccoli and cauliflower are known to have high boron needs.
On the other hand, too much boron in the soil can be toxic to plants, causing yellowing and browning foliage and brown leaf tips. If your soil test shows excess boron, test your garden water supply. Spring water and well water can contain higher concentrations of boron than plants can handle. If your water also shows high boron concentrations, consider a rainwater capture system to collect water for irrigating your garden, and water deeply to help leach some boron out of the soil.