Preventing Weeds with a "No-Dig", "No-Till" System

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Q. Mike: I just purchased a home and want to get the ground prepared for a ""no dig"" organic garden next year, but I'm not sure where to begin. The main reason I want ""no dig"" is to avoid back pain. A UK organic gardening Internet site I consulted lists other advantages, including reducing moisture loss and protection of soil structure and topsoil. The disadvantages were that some people like digging (I don't), that it takes longer to improve poor soils, and does not deal with compaction and ""hard pans"". (I have no idea what that last thing means; can you please explain?) I am willing to dig once to build the garden as long as I don't have to till it year after year. Thanks,

---Jude in Phoenixville, PA

For eight years I have been unable to stop the weeds from overtaking my vegetable garden. I have used mulch and plastic mats. Do you have any suggestions?

---Hugh in Burton, Michigan

Mike: I just moved into a new development and want a beautiful vegetable garden and lawn. All the topsoil was removed when they built the houses. What would you suggest I do to have great soil and a beautiful, lush backyard? Thanks,

----Stefanie in Mt. Holly, New Jersey

A. Let's get Stefanie a lawn first. You—and most other folks in the North—want a cool-season lawn, so get to work, because Fall is the only time to successfully plant one! Now, if you wish to completely follow the dictates of the ""no dig"" method we're covering this week, you would bypass the traditional tilling up of the existing soil. To 'no dig' a new lawn you would instead cut whatever's there as short as you can, and have a big load of compost or aged mushroom soil delivered and dumped on top to smother the old stuff and provide a weed free planting bed. Level that new stuff out to around an inch deep, water it gently, spread the new seed, cover with some more compost and mist lightly twice a day until it sprouts (which will be fast at this time of year).

Feed your new lawn correctly (that means corn gluten meal at the right time early next Spring and compost or more corn gluten or some other form of nice gentle organic lawn fertilizer in the Fall), keep it cut high and all should be well. (See these previous FALL and SPRING lawn care Questions of the Week for all the juicy details.)

But if this WASN'T ""no-dig"" week, we would suggest you till up your existing soil, rake out as much green as you can, level it all out, then apply the compost overtop and seed. The potential disadvantage to this method—and the overwhelming benefit of no-dig, no-till systems—is that tilling and digging uncovers enormous numbers of buried weed seeds, some of which might well migrate through that new layer of compost and reach the surface of the soil, where they would sprout and compete with your grass seed.

But doing this in the fall, when cool-season grass is the plant from Krypton, should give the edge to the grass over the weeds. (The reverse is why Spring sown cool-season lawns are always a weedy mess; weed seeds have the upper hand in Spring). And that initial tilling will greatly improve the drainage under your new turf—which could be really important if the soil is as poor as you imply.

That's the same basic choice you face in creating a no-dig veggie garden: Whether to till it all up first or not. Whichever you choose, you should definitely build raised beds to not dig in. And building those beds now will give you the whole season to grow lots of tasty treats in them next year.

We've covered raised bed building in great detail in two previous Questions of the Week (click HERE and HERE to read them), but the basic idea is to simply raise your growing areas six inches to a foot above the surrounding walking areas and frame them out with non-toxic wood (no old railroad ties!) or stone. This solves the soil compaction problem that always occurs in flat ground gardens, whether they're no-dig or not, because the frames remind you to never step into the beds. No big feet in the beds means the nice loose soil you start with stays nice and loose, which keeps plant roots happy and healthy. Compacted soil makes plants sickly and sad. (""Hardpan"" is soil that's been compacted to the level of concrete.)

If you want to be no-till from Day One, build your beds right over top of your existing soil. Have a big load of compost and a big load of topsoil delivered, mix them equally (or buy a 50/50 blend if its available), and use this fine mix to fill your frames, which can be as long as you want, but no more than three or four feet wide so you can reach the center of each bed from either side without stepping into it. Immediately cover the top of that new soil with a couple inches of shredded fall leaves to prevent new weed seeds from blowing in; and mulch the walking lanes heavily with old carpeting and/or wood chips to prevent weeds from sprouting out there. It's fine to use wood chips or shredded bark in the lanes, but don't mulch the beds themselves with any kind of wood.

In the Spring, gently move the leaf mulch aside for a few days before you plant each area to let the soil warm up, and then re-apply that mulch right after planting. If you keep an inch of that perfect mulch on the surface of your soil, you shouldn't ever see a weed; so be sure and stockpile lots of shredded leaves this Fall. Those leaves will also slowly feed your soil as they decompose. And I don't know about their 'no-till' preferences, but earthworms love living under leaf mulch.

If you don't mind tilling once to get started (which I really recommend if your soil is rock hard clay), till up the entire area first before building the beds. If you want to do this but would like a little extra insurance against weeds, till everything up, level it all out, wet the soil, wait a week for all those weed seeds you uncovered to germinate, hoe them down and then build your beds. (An old technique known as the 'stale seed bed' [don't ask me why], this eliminates much of the weedy potential that digging and tilling entail.)

Either way, you shouldn't have to till again. Or spend your summer pulling weeds.

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