Once a soil test (county extension agent) reported low boron in our garden. It explained the distorted radishes. Since then we've used a lot of compost and cover crops and things are fine. But we have a small patch of strawberries off in a different place and they are small and gnarled in a way that some have diagnosed as possibly boron deficient. I would like to add some. I assume I'd use either Borax (do they still make that?) or boric acid. But I have no idea about the amounts. Anything I find is discussed in terms of acres and hectares, etc., etc., and I can't face that much math. I wouldn't trust myself. Any advice?
I just looked up the application rate of Boron for legumes and it says .5 to 1 lb per acre. It also shows that Borax is 11% Boron. That means that you need about 10 pounds of Borax per acre. Dividing that by 43,000 which is the approximate square feet per acre. gives you 0.00022 pounds per square foot or .36 ounces per 100 square feet. Granular Borax weighs 60 lb per cubic foot which converts to 1/2 ounce per tablespoon. I think 1 to 2 teaspoons per 100 square foot is fine. That is a space 10 foot by 10 foot or one that is 3 foot by 33 foot.
What I read is not to get it on the leaves. what I would do is put 1 or maybe 1 1/2 teaspoons in a five gallon pail and use a cup measuring cup to water approximately a square foot area.
I hope this helps.