Posted By Brock Mashburn
At the Seed Bank in early November, we started to notice a common problem around the farm. In many areas, quick growing weeds were showing inter-veinal chlorosis (yellowing between leaf veins) and even necrosis on the growing tips. These symptoms are common to find with a few nutrient deficiencies, but our observations and laboratory testing led us to settle on a boron deficiency as our culprit. We also noticed similar symptoms in one particular patch of Hawaiian chili peppers. Being the spicy food lovers that we are, we wanted to cure our plants, and the weeds offered a great spot for experimental freedom.
Boron is an essential micronutrient in plants. Although only required in very small amounts, it plays a pivotal role in cell wall strength and development, cell division, and fruit and seed production. Boron is not commonly found in nature and washes away easily in acidic soils. In many areas of the world, it is consistently deficient in soils, but it is also potentially poisonous to plants at higher levels.
We wanted to give Boron to our plants while avoiding chemicals, processed products and generally having to spend money, which led us to reference Dr. Arnat Tancho’s book, Applied Natural Farming. This book is an excellent resource for appropriate and organic farming solutions and methods (and available for purchase at the Chiang Mai ECHO Asia Impact Center). Especially of interest to us was “Chapter 6: Production of Fermented Bio Liquids,” with section 10 conveniently being “Fermented Liquid Boron.”
Dr. Tancho provides two recipes for producing a Boron spray: one from ripe guava fruit and one from dried horse manure. Fortunately, we were able to acquire both quite easily. The guavas were cut into cubes while the horse manure was dried and crushed into a powder. Each was mixed with molasses (wood vinegar works as well) at a rate of 3 parts guava to 1 part molasses or 1 part horse manure to 10 parts molasses. We left each mix to ferment 9 days and soon we had a sweet smelling liquid that we could dilute 200 times in water to spray on the soil, plants and especially flowers to promote fruit set.
Over the last 3 months, we have been wetting the leaves and soil of our peppers and have noticed a significant improvement to the inter-veinal cholorosis. The plants have been putting out more young growth with dark green leaves without any noticeable difference between the two recipes. Unfortunately, our weeds were already at the flowering stage early in the experiment, so we didn’t see much difference in new growth in them after being sprayed.
Of course, both fermented liquids are quite rich in other nutrients as well, so it is hard to conclude that the Boron was the main factor in the peppers’ improvement. However, it is quite encouraging that various bio-liquids can be made from on-farm inputs that can help to correct nutrient deficiencies and improve plant growth and health.