Plant Ally: Buckwheat
The many moods of buckwheat, Fagopyrum esculentum
I keep a stock of buckwheat seeds at the ready all summer long. I use it as a summer cover crop in
vacant areas, and squeeze small plantings of it here and there to attract pollinatrs and beneficial insects. It has a lot of value to me as a multi-functioned, easy to grow annual. It grows quickly, even in poor soils, is somewhat drought tolerant, and decomposes quickly when incorporated as a cover crop. Its delicate roots do require friable soil though; it won't establish itself well in a hardpan.
As a cover-crop:
Buckwheat is an all-star as a summer cover crop. Planted densely, it's a great suppressor of summer weeds and grows quickly. The planting window is very narrow though. Buckwheat is not frost hardy, and flowering and seed set are day length sensitive.
Buckwheat and rock phosphates:
Phosphorus is a tricky nutrient to supply organically and in my soil type, I need to supply it. Read about my adventures in providing phosphorus organically with rock phosphates in arid soils Here:
Read about my adventures in balancing soil nutrients Here:
Buckwheat is purported by a number of sources to accumulate phosphorus in its tissues by solubilizing phosphorus in the soil. This is done as the roots release acids which act to break down rock phosphates and other sources of phosphorus. As the crop residue breaks down upon incorporation into the soil, this phosphorus, as well as other nutrients accumulated in the tissues, break down and become available to the subsequent crop. Cornell University Horiculture touts buckwheat as “the most effective user of rock phosphates.” This ability to make phosphorus from rock phosphates more available is one more potential tool for making the most of (expensive) rock phosphate applications (see applying rock phosphates.)
Pollinator and beneficial insect attractant:
Buckwheat patches make great pollinator watching. The shallow flowers and dense plantings mean a lot of accessible nectar in a small area. The pollinators and other beneficial insects I most see in the buckwheat patch are:
Buckwheat easily resows itself, so be careful if you don't want to be weeding it out of the field for all eternity! Luckily it weeds very easily; in the early stages root and all will come out if you gently run your hoe over it. I wouldn't want an entire field reseeding, but since I will mow the bulk it down before it even flowers, I don't worry about some that flower and go to seed unintentionally. They will grow the following year and I'll either weed them or leave a few random buckwheat throughout the field for attracting pollinators and beneficial insects.
Grow buckwheat for next year's seeds, or for making buckwheat flour or groats for eating. Probably ninety percent of my buckwheat consumption is in the form of buckwheat crepes, where it really shines. Buckwheat grown for seed should be planted at wider spacing than that grown as a cover-crop.
Planting buckwheat too early, before mid-June, causes the plant to flower early, develop fewer flowers, and thus fewer seeds. It could still make a suitable cover crop to be tilled in though.
Harvesting the seeds is tricky and it takes a few seasons to become acquainted with how the plant matures its seeds. Seeds develop in different locations on the plant depending on daylengths as the seed is maturing. Cornell University recommends planning for seed maturity to take place in mid-August. Buckwheat takes 70-90 days to mature seeds, so this means planting in late June to early July. According to Cornell, ripening in August when the daylength is shorter means more seed is set on earlier nodes and maturity is more concentrated.
The cascading clumps of flowers ripen their seeds progressively, so planning for more seeds ready at one time by planting at the right time is important to final yields. While some seeds in the cluster start to fall at maturity, others remain green. On a small scale, progressive ripening can be managed by shaking the seed cluster into bags every few days (they mature and drop that quickly!) Dry, mature seeds will fall into the bag. Alternatively, cut the plant at the base of the stem when most of the seeds are mature. Hang them in a bag or over a tarp, allowing any remaining or maturing seeds to fall. At a larger scale, harvest the seed heads when most of the seeds are mature. You will lose a few of the early ones to the ground, and you will harvest some that are immature. These will be lighter than the mature seeds, so they will sort out with the chaff when the seeds are cleaned.
Buckwheat is not at all hardy and will winter kill at the first sign of temps near freezing. If its in the later stages of growing a dense planting will form a staw-like mat that can serve as a winter mulch protecting the soil.