20 Mule Team Borax. It contains a natural substance -- sodium tetraborate -- that organic gardeners value for two primary purposes. As an herbicide, it kills any invasive weed; and as a fertilizer supplement, it provides the micronutrient boron to plants.
Boron is the lightest metalloid element that exists in nature. It is not a free element, existing alone, but it is found in chemical compounds such as borax. Borax is the common name for the chemical compound sodium tetraborate decahydrate, which contains sodium, boron, water and oxygen. Because this compound is produced as a natural residue from the repeated evaporation of seasonal lakes, it is suitable for the organic garden. Even though boron and borax are organic substances, this does not imply that their misuse is harmless to your plants. It simply means that they occur in nature instead of being chemically synthesized in a laboratory.
California is home to one of the world’s largest borax deposits from which 20 Mule Team Borax is manufactured. This product is packaged in its pure form, with no chemical additives. The only processing it receives after its removal from the ground is washing, drying and packaging. The company claims its product is 99.5 percent pure, with the remaining 1/2 of 1 percent containing naturally occurring trace minerals. The use of the product in the garden is considered organic because it eschews synthetic chemicals by using naturally occurring substances that are minimally processed.
Fertilizers contain varying levels of nutrients, depending on plants’ needs. Some primary nutrients, such as nitrogen, phosphorus and potassium, are needed in larger amounts, while others such as boron are called micronutrients because they are needed in trace amounts. Some plants, such as the cole crops that include broccoli and cauliflower (Brassica spp.), need boron in slightly higher amounts than other plants. Boron deficiency symptoms may appear as hollow broccoli stems or brown cauliflower heads. If a soil test shows a boron deficiency, you can use 20 Mule Team Borax to correct the problem. Following soil-test recommendations, broadcast 1.5 to 3 pounds of 20 Mule Team Borax per acre when you apply fertilizer. For smaller gardens, sprinkle 1 tablespoon of 20 Mule Team Borax for every 100 linear feet. You can make a foliar fertilizer by mixing 0.2 to 0.3 pound of Solubor, which is manufactured by 20 Mule Team Borax, in 30 gallons of water and applying it per acre. Adjust the amounts for your size garden.
Gardeners have used 20 Mule Team Borax since the 1920s to control weeds. In U.S. Department of Agriculture plant hardiness zones 4 through 9, creeping Charlie (Glechoma hederacea) grows as a perennial weed that invades turf, flower gardens and mulched areas. This aggressive mint-family (Lamiaceae) plant can send stems up to 2 1/2 feet long in all directions. To control this weed, the University of Minnesota Extension recommends using borax as an effective herbicide by first dissolving 10 ounces of 20 Mule Team Borax in 4 ounces of warm water and then adding the solution to 2 1/2 gallons of water. Apply the herbicide to creeping Charlie with your garden sprayer."
My soil and tissue tests are all very deficient in Boron. Creeping Charlie is taking over the old home place. The plan next year is to start using Boron around the farmstead.
Is your farm, lawn, or garden deficient in Boron? It is the most consistently deficient element of the 17 essential nutrients I have tested for over my career.