As the world turns: reflections on daylight, temperature, and why you need to seed your fall cover crops NOW

Update February 2015: read more about Jan’s work in this more recent post, with links to an eOrganic webinar he presented in January, 2015.

Back to the original post…

If you’re in the no-till vegetable world (especially if you’re an organic grower), you’ve either met Jan or you will meet Jan over the next couple of months.

Jan and Natalie during Jan's visit to Maine. A baby forage radish was sacrificed for this photo.

Jan and Natalie during Jan’s visit to Maine. A baby forage radish was sacrificed for this photo.

Jan-Hendrik Cropp is an organic no-till enthusiast from Germany who is learning everything he possibly can from those of us trying out bits and pieces of organic no-till in the states. After his trip, I may just hand this blog over to him. But before that, I want to highlight a couple of big differences between crop production where Jan is and where we are (the Northeastern US), all with the take home message that if you want good enough cover crops for no-till next year (both high-residue and low-residue), you need to start putting seeds in the ground NOW (well, depends where you are, but very soon!). Forage radish needs to go in before overwintering cover crops like rye and vetch.

Jan was startled that all the farmers and researchers here in the Northeast have insisted that an early seeding date  is essential to any cover crop-based no-till production. In Germany, despite being farther north even than Maine, they can seed their cool weather legume/grass cover crops in October and still get great biomass in spring. In the mid-Atlantic, September 15 is optimal for rye/vetch (see Rodale’s Beyond Black Plastic report). I told him that despite the summer heat, we have COLD winters here in the Northeast. The weather data show that, indeed, German winters where Jan is are more mild than even mid-Atlantic winters.

Click for larger version.

Click for larger version.

And what about daylight? Mightn’t the shorter late fall days in Germany negatively affect cover crop growth? Perhaps, but in this case temperature might trump daylight. This isn’t meant to be all sixth grade science-y; I was just trying to understand why they can seed their grass/legume cover crops so late (darn them!).

daylightWhatever the reason, they can seed rye, vetch, and peas in October and get great biomass production for no-till. Research and experience shows this is just not the case where we are. High-residue cover crops need to be able to put on enough growth in fall to really take off in spring and provide the biomass needed for adequate mulch-based weed suppression. Forage radish–the only low-residue cover crop we’ve found that works really well for no-till in spring–needs an early seeding date for canopy closure and weed suppression. No way around it.

Despite some climatic differences, much of the work Jan and his colleagues have been trying out in Germany has great potential here, too. In fact, some of what they’ve been investigating is bolstering weaker cover crop performance with “chopped and carried” material from clover/grass fields in rotation. This has enabled them to do no-till transplanting without herbicides even when they don’t have quite enough biomass in the cover crops alone. They’ve even developed a pretty neat transplanter for this system.

This transplanter was designed and engineered by Jan-Hendrik Cropp and colleagues in Germany.

This transplanter was designed and engineered by Jan-Hendrik Cropp and colleagues in Germany.

Once he’s done with his US tour, we’ll put together a summary of their work and share it here. They have some information in English on their website if you’re eager.

In the mean time, seed your cover crops now so you’ll be a happy farmer next spring!

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