Fracking Daikon Radish is a deep rooted forage radish that will make an outstanding winter cover crop. The deep taproot of the large rooted plant can help break up the tough, compacted soil, improve water infiltration, suppresses weeds, eliminate pests and stores nitrogen. When planting daikon radish seed as a cover crop, the benefits will be optimized if planted in late summer:

Among many other benefits, daikon is renown for softening the soil. As Fukuoka simply states, “if the soil is hard, grow Japanese radish first.”

Natural farmers have known this truth for generations. Now, even big agriculture praises it’s effects, as corn, wheat, and soybean producers add tillage radish to their rotations.

Daikon captures last year’s nitrogen, so you don’t have to fertilize. Softening soils is not the only reason to use daikon as a cover between fall and spring crops. It’s deep roots recycle last year’s nitrogen, catching it before it drains out over the winter. Because daikon decomposees so quickly in areas where it naturally dies over winter, that nitrogen is released in the spring for the next season’s use. In one study, this amounted to 170 lbs N/acre – more than enough to meet vegetables growing needs.

Revitalize soils with fall-planted Daikon--To transform soils in a single season, daikon magic works best in zones where heavy frosts of below 25 ° F naturally kill the cover over winter, so that soil life has time to chew and transform the decomposing crop before spring. In climate zones that don’t have heavy frosts, harvest daikon as an overwintered vegetable and turn the residue back into spring soils. With this method, compacted soils can loosen over a couple of seasons. For natural, wild gardens, let the daikon radish flower in the second season to reseed. In this way you can introduce this phenomenal soil builder into your wild plant guild.

Plant daikon a little earlier than other over-wintering cover crops to give it time to grow a thick leaf canopy. Aim for 4-10 weeks before the first frost – late August in cooler climates, early September in warmer ones. Like all cover crops, how much seed you use depends on how you garden, seed costs, and your goals (more on this in future posts). In the garden, I use cover crop seeding rates up to 10-20 times higher than farm recommendations. For a quick cover that suppresses weeds, I’ll use 1/4-1/2 a pound per 100 square foot of garden, broadcast and scratched into the top 1/2 of the soil surface. For my no-till beds, I might double this rate, since new plants will be competing with mulch and residue already present on the surface.

Daikon is a type of oilseed radish that is bred as a garden vegetable. This variety will certainly work as a cover crop if you can find an inexpensive seed source. Otherwise, you can order cover crop seed for daikon-type radish under the names tillage radish, forage radish, fodder radish, or groundhog radish.

To use these radishes to their full potential, producers should do all of their land preparations in the fall (pulling beds, etc.) with the intention of planting the following cash crop in the spring with no tillage. One of the primary benefits of the radishes are the “holes” or cavities left when the root dies and decays, which allows the soybeans or other following crop roots an easy channel to bore deeper in the soil profile.

If you plant radishes and then do your normal tillage operations in the spring prior to planting, you are potentially wasting one of the benefits of the radishes.\

Minimum soil temperatures for radish germination is 45 degrees F, so they can be planted late in the fall and still germinate. However, late-planted radishes do not have adequate time to grow and develop the large taproot or above-ground biomass critical to their success as a cover crop prior to the cold temperatures that restrict growth during December to February.