Posted by Rooster on May 21, 2015
Boron is low in typical New England soils. Crops that respond well to boron include beets, brassicas, potatoes, and tomatoes ... and chili peppers, of course. Boron helps plants move nutrients from the roots up to the top of the plant. Don't over do it. High levels of boron are toxic to plants. Have your soil checked at, for example, the UMass Soil Lab. Boron levels in the soil below about 0.15 ppm indicate the need for supplementation. Do not supplement if soil levels are much above 1 ppm. Your lab results will be your guide.
If boron supplementation is indicated, a convenient source of boron for your garden is 20 Mule Team Borax. Here's the formula to mix and apply to achieve about 0.8 ppm additional boron in the soil. Per 100 sq. ft. dissolve 1 1/2 TBL Borax in warm water and drench soil. Adjust the quantity of Borax depending on the area you want to treat. Quantity of water is not important as long as you have enough to evenly cover the intended area. One gallon is about right for 100 sq. ft. Water is just the vehicle for the Borax. Avoid contact with leaves of your plants. The concentration of this soil treatment may result in leaf scorch. Foliar treatment is also helpful for increasing yield and disease resistance, but use a solution with a concentration of about 0.2% (1 tsp/gal).
A box of Borax is 100 year supply. Buy a box. Use it. Share it with your friends and fellow gardeners!
Special thanks to Derek Christianson at Brix Bounty Farm in Dartmouth for this information. He lead a discussion on Secrets of Soil Nutrition in March at the 3rd Annual Urban Farming Conference.