Cultivating Questions

Concerning the Bio-Extensive Market Garden

by Anne & Eric Nordell of Trout Run, PA

Mulch Tilled Sudex and Clover

1. Sudex and clover planted middle of June. We find that both types of seeds benefit from being planted 1” deep at this time of year and will emerge from this depth in warm, dry soil in just 4-5 days. We simply broadcast the seed together, then harrow very lightly before firming the soil with the cultipacker. Even better, seed separately by harrowing in the sudex, rotary hoeing the clover, then rolling.

2. First cutting of sudex approximately 40 days after planting. Mowing at this stage of growth prevents the high carbon biomass from getting tough and woody, and forces this drought resistant cover crop to put its roots deeper in the soil. According to research conducted in New York, managing the sudex this way can alleviate soil compaction. Pressing lightly on the mower’s lift pedal raises the cutterbar 6-10” off the ground, encouraging faster regrowth of the sudex without setting back the shade tolerant medium red clover getting established in the understory. Mowing the second cutting of sudex close to the ground does a better job of finishing off summer weeds before they can set seed and reduces the size of the sudex stumps which can interfere with direct seeding vegetables the next year.

3. A late fall photo of frost killed sudex regrowth following the second cutting in mid-August. Meanwhile, the clover has produced almost 100% ground cover by the end of the summer, preventing fall weeds from getting a foothold.

4. Applying 6-8 yards/acre of hog composted horse manure before incorporating the overwintering clover and frost-killed sudex enhances decomposition and provides some slow release nitrogen to complement the quickly available nitrogen in the clover.

Due to the unusually early spring drought we faced here in 2006, we decided to setback the clover prematurely the first week of May before it had put on more than 5-6” of topgrowth. Lacking irrigation, we thought it was more important to prevent the legume from taking more moisture out of the soil then to maximize nitrogen production.

5. As an extra measure to conserve soil moisture, we decided to mulch till the clover and sudex stubble rather then shallow plow the bone dry sod. We used three shanks, 17” apart, on the old riding cultivator, two on the outside of the gangs lined up with the horses and wheels, and one in the middle mounted on a cross bracket at the front of the cultivator. Setting a horse, wheel and outside shank in the last furrow made with each pass, defined the planting beds right from the start and reduced the horsepower requirements for Becky and Ben.

6. The first time through the field we attached 4” sweeps to the three shanks to rip open narrow furrows in the dense clover root system without causing too much of a pull for the team or the antique implement. Next time over we replaced the 4” sweeps with 8” sweeps, undercutting more of the sod, then 12” and finally the 18” sweeps shown here before a final pass with our regular 5 sweep setup (illustrated in the DVD). Yes, it took five trips through the field to completely undercut all the clover…

7. …but by the end of June the cover crop was 99% dead in the planting beds and the surface mulch of decomposed sudex residues absorbed a drought breaking rain without any runoff, holding the precious near the soil surface so we could begin transplanting and direct seeding in July on schedule.

8. No doubt in our minds that the mulch tilled sudex and clover helped these fall crops of brassicas alternating with lettuce, spinach and salad mix get off to a good start despite another long stretch of hot, dry weather which did not break until tropical storm Ernesto blew through at the end of the summer. (For added moisture insurance, we applied a light mulch of wheat straw in the pathways.) Crop growth across this half-acre field was consistently healthy and vigorous regardless of large variations in soil type from well drained sandy loam to poorly drained clay loam with a fragipan. In terms of fertility management, we imagine the clover provided a quick flush of nitrogen to prime the decay process and early crop growth, but the long term plant energy that allowed the heavy feeding brassicas to go the distance came from the compost and carbo-loading the soil with the clippings of sudex during the preceding fallow year.