Q&A

Editor’s note: This email exchange with Rodale Institute Research Agronomist Dave Wilson began April 30.

DEAR NEW FARM:

I would like to, within a week or two, plant a stand of buckwheat as a cover crop. After five to six weeks, it would be mowed down with either a sickle or flail mower. I would then plant pumpkins, watermelons and squash by seed and transplants.

I'm not farmer, however I understand that buckwheat does not contribute anything in the form of nitrogen. Does this sound like a worthwhile plan, or would the buckwheat pull needed nutrients by the subsequent crops? The fact that buckwheat is a fast grower is the main reason I want to use it.

Thanks for any thoughts and suggestions,
Tom Dunnock
Pennsylvania

DEAR TOM:

You're right. Once the soil warms up then the buckwheat will germinate quickly, and it grows quite fast. If planted thick enough, it does help suppress weeds. After you mow, it will break down rather quickly as well, so it doesn't contribute much to building up organic matter. But it does release an enzyme that helps make the phosphorous in the soil more available for the next crop. If you leave it on the surface, it won't stick around that long once it starts to break down. It doesn't take up much nitrogen, but if you leave it on the soil surface the nitrogen that it does take up in its tissue will be released to the atmosphere through volatilization as it breaks down; if you incorporate the residue, it will go back into the soil. Because it breaks down quickly, the nutrients it took up will be released and go back to the soil mostly this season. If you don't want to till you can mow it, leave it on the surface, put your transplants in and then mulch with a straw mulch around the transplants to keep the weeds down. Buckwheat isn't a legume and doesn't fix any nitrogen, so you are correct that you won't get any added nitrogen benefit from it.

Another quick grower is spring oats, which you can plant like the buckwheat. The oats will probably grow a little quicker than the buckwheat at this time of year. They would also give you a quick cover, but not being a legume won't give you any nitrogen. They won’t die as easily by mowing, so you would have to incorporate them into the soil by shoveling or rototilling. The buckwheat will kill more easily than the oats.

If you need quick available nitrogen for your squash, pumpkin and watermelon, then you should add some manure or compost.

If you do want to try to grow some nitrogen, then Canadian field peas are about the best to plant in the spring. How much growth you will get out of them will vary with the climate. We planted some peas here at the end of March this year, and they just sat in the ground for most of April because the soil temperatures were cool with this cool spring. They finally germinated and are now growing. I think if you planted those now you will get a quicker germination with the warmer soil temps. Our soil temps are up to 50° to 55°F now [May 2].

So here are a few options for you. Buckwheat is fine, but you won't get any nitrogen. The Canadian field peas will give you some nitrogen, but I can't guarantee how much in 5 to 6 weeks. It depends on the growing conditions.

I hope you find this information helpful, and happy planting!
Dave Wilson

DEAR DAVE:

Thanks for your reply and information. And, yes, it was very helpful. I neglected to state that my main purpose in planting buckwheat first was so that it would act as a mulch after being cut down. But from what you're saying, it doesn't stick around long enough to do that. Would planting an extra-thick stand be successful toward that goal?

Also, I'm in the process of having a house built and would like to incorporate a root cellar in the foundation. Is there someone at Rodale I could talk to about this? I'm being told by the builder that root cellars have traditionally been built apart from the house. He's concerned that it will allow easier access for rodents and insects. Obviously it would be more convenient if I could access it from the inside. Hope you don't mind the questions. This should do it for now.

Many Thanks,
Tom

DEAR TOM:

Yes, you can plant an extra-heavy stand of buckwheat and that may stick around a bit longer, but I'm not sure how long. The buckwheat stems don't have much lignin in them, therefore they start to decompose and breakdown relatively quickly; a heavier stand will help because there will be more material there. If you can straw mulch on top of that, then that will help.

For gardeners, I like to recommend straw mulching with oats, wheat or rye straw. Oats and wheat straw are more commonly found. The straw gives a nice weed-suppressing mulch, and because it has a high C:N ratio (it has a lot of carbon in it compared to nitrogen) it doesn't break down that quickly. I put some straw on an herb garden last fall to protect the herbs over winter. This spring I pulled the straw back, and I can still use it on another part of the garden as mulch. Straw sticks around a while, especially over winter; it doesn't break down at all. Over winter it acted as an insulating blanket, and in the summer as a weed-suppressing mulch. It will start to slowly break down as the temperatures warm up.

Years ago, my grandfather built his own root cellar inside the regular cellar. It doesn't have to be a separate structure. He built heavy shelves against the wall; some of the shelves he filled with soil and that is where he would bleach his endive. The people back then used to like to buy the "bleached" endive from him. (Bleached was the term for "white"; they didn't really use bleach.)

The other shelves had no solid bottom, just a frame to which he attached chicken wire. The fencing allowed for air flow through the shelves. This is where he would store his vegetables.

Most cellars in the past weren't heated, so they were cooler and damp. I think if I were building a root cellar inside a regular cellar, I would build it in the corner with cinder block walls to have a walled-off room inside the cellar itself with two of the walls being the outside foundation walls. Then follow the air-flow ventilation plan listed below into that room to keep it cool. The cinder block walls on the inside of the root cellar can be painted or left as is, on the side toward the cellar they can be finished off, studded out and insulated on the inside of the cellar to keep the rest of the cellar warm. Close off the room with a heavy insulated door.

There is a lot of information on the Internet on building a root cellar. I typed in the words "Building a root cellar" and clicked to do a search. Organic Gardening magazine is one the sites that came up with information. They give instructions on building a root cellar inside your existing cellar, as you are interested in doing. They suggest just building a room and making the walls out of rot-resistant wood and moisture-resistant wall board. I guess that would be the less-expensive route. Still, I think I would use cinder block.

If you talk to the contractor before he pours the foundation, you can have him lay the PVC pipes for ventilation right through the foundation wall form before he pours the concrete, and then have the foundation wall poured around the pipes. Sometimes this is done for electrical conduits or sewage lines.

Hope this is helpful,
Dave Wilson

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