I'd till the grass under about a month before planting (a lot of work without a good tiller). This "green manure" will benefit your soil. You just need to make sure that you allow enough time for decomposition before you set out your tomatoes.

I tilled the grass in when I made my bed. Biggest garden mistake I ever made. I had weeds for YEARS. I recommend renting a sod slicer/cutter and removing the sod level. You can use it to patch bare spots in your lawn or chop it up and compost it.

The no-till floks would recommend that you smother the grass lasagna-style and plant through it.

But under no circumstance would I EVER till in the sod again.

I also vote for no tilling. I made the mistake of tilling under my lawn, and Oh, My, it took me YEARS to get the weeds out! I finally let it go fallow for one year, put black plastic over it, and let it solarize -- because all I was doing was pulling weeds non-stop. Then when we put in another bed, we got a sod cutter, took off the grass, worked a mixture of compost and topsoil into the top, and never had a real problem with weeds there. The difference between the beds was day and night. Under NO circumstances do you want to till! It just brings up every dormant weed seed that has been waiting around for this very opportunity to get started, and once started --Geez! -- one 3-week vacation and I couldn't even see the rows in my garden because they were choked with weeds! I hope this helps. MacThayer

All of the above posts are correct in part.

Tilling in the sod has the advantage of adding organic matter to the soil, and opening up your soil for aeration, improving the tilth.

However, it also brings up TREMENDOUS quantities of weed seeds, all just waiting for a little light to begin to grow. And, you would probably have to till every few weeks for several months to get all of the sod to die.

My personal recommendation -- 1) At least a month before you want to plant, spray the entire new bed area with Roundup or another systemic herbicide, to kill the sod. 2) After the sod has turned brown, till the area thoroughly and as deeply as possible. 3) Wait about 2 weeks, then topdress with all-purpose fertilizer and/or organic matter (compost, peat, etc) and till deeply and thoroughly again. 4) Wait about 10 days to 2 weeks, then till deeply again. 5) After the last tilling, cover the entire bed with 6 mil black plastic.

This approach combines the best of both worlds. And, tomatoes LOVE black plastic mulch, especially here in Michigan. It keeps in the moisture, keeps down the weeds, and keeps the plants clean and the foliage relatively dry, helping to prevent diseases.

If you do the herbicide and first till by May 1st, you can have the bed ready to set out you plants by Memorial day weekend, which is really just about the best planting time in S.E. Michigan - not too early, when its too cold, and not too late.

denninmi, whereabouts in mi. are you? Thank you all for your input.

Dale

Why can't you till the grass and then spray an herbicide to kill any weeds that may sprout up? Problem solved, so long as you allow enough time for the herbicide to break down before planting your tomatoes. Removing the sod sounds like more trouble than it's worth. Also, grasses are common cover crops that are routinely tilled - farmers do it all the time. Weeds are always going to sprout in bare soil, so I don't see how removing the sod is going to make any difference. Plus, isn't mulch supposed to take care of weed suppression? Why not just mulch around the tomatoes to prevent weeds?

Would'nt tilling everything under as seedboy suggests then covering with clear plastic for a couple of weeks kill everything? As long as the temps under the plastic got up in the 120's or hotter.

Dale

If you cover it with plastic (or landscape fabric) it will kill the latent grass eventually. You'll only get grass around the edges.

I mulched with black landscape fabric last year and plan to do it again. Not having to weed was nice. You have to pay more attention to proper soil moisture, though: not too much, not too little. I let mine get too soggy.

i do not mean leaving it on for good just for a couple of weeks so that all the seeds in the soil will get killed off. will raising the temps up over 125 degrees kill off all weed seeds?

Dale

Use the Roundup to kill the grass/weeds before you till. Then you can just rake the dead grass/weeds away. Then spread some organic matter and/or fertilizer and work it all in together when you till it. After tilling you can apply some sort of mulch if you so choose.

Alan