Using plastic to weed the garden : LUSENET : Countryside : One Thread

Being by myself for the first season in six years, I had to figure an easier way to weed the garden. So while shovel turning it, I laid down clear plastic and pinned it with garden soil on all edges to seal it down. the internal surface temps raised to 115 degrees in less than an hour under direct sun. I figure to leave these sheets in place for 30 days and turn the soil once more before final cultivation and worm cast additions to re-establish the microbe populations. Do ya'll think this will kill most of the weeds?

-- Jay Blair in N. AL (, March 06, 2002


It will kill some of the weed seeds, but not all of them. We use black plastic for gardening since I have some limitations. We've found that it takes a few years to get rid of all of the weeds. If I remember correctly, some weed seeds can survive in the ground for seven years.

-- Ardie/WI (, March 06, 2002.

Hi Jay,

It's called soil solarization and I think the reccommended time frame is 6 weeks to kill all grass, weeds and seeds in the top 4 inches of the soil.

My problem is finding clear plastic sheets that will not degrade into crumbles from the UV exposure. Any clues on that?

-- Laura (, March 06, 2002.

Laura is right, but the recommended time to kill ALL the weeds and grasses is a full 6 months . You might try you immediate plan this year, and institue the 6 month plan after harvest. This really does work . I try to resolarize every 3-5 years. Really cuts down on the weeding. The first year or two I will have NO weeds, but due to winds and birds ect.. will have a few in year 3 so I do it again. Happy gardeining, Kristean

-- Kristean Thompson (, March 06, 2002.

Hi Jay,

If you turn the soil after solarization, you will just bring to the surface the seed bank that has been happily sleeping down there.

If you are really worrying about the weed load, you could just plant through a weed barrier fabric after adding your amendments. If you mulch the fabric after planting, you will avoid cooking the young plant's roots and your fabric will last more than a season. I have had good luck planting through black or white single season plastic with either srip irrigatin tubes underneath, or with surface lines with lateral emitters for the plants...tomatoes, melons, squash, etc. We went to the fabric to avoid the labor of those two irrigation methods and it was less expensive and had less environmental impact in the long run. Mind you this was large scale growing.

On a smaller scale, I might solarize in the spring after turning and harrowing. Then plant, and then mulch heavily.


-- Oscar H. Will III (, March 06, 2002.

I am seriously considering black plastic with row openings and wick cans for watering.

-- Jay Blair in N. AL (, March 06, 2002.

I have done the black plastic - I put it down in the fall, and left it over the winter. I'm sure it had six weeks of heat in the spring before I was able to plant. This was on a section of 'lawn' that was essentially quack grass with a sprinkling of pig weed, sheperd's purse and dandelions.

I need a new section of garden this year, and I'm going to try planting buckwheat. Apparently it grows in a rather dense mass that is hard for weeds to survive in. Then you till it under just as it blossoms. This adds humus to the soil, and if I'm not mistaken the buckwheat sets nitrogen as well. I'm sure this won't get all the weeds, but it will help I'm sure.

-- Bernie from Northern Ontario (, March 06, 2002.


In response to the buckwheat comment. Buckwheat (Fagopyrum esculentum (grain buckwheat) and other species are in the rhubarb family. Members of the genus Polygonum are also carry the common name buckwheat or wild buckwheat. These plants are not legumes, nor are they able to fix nitrogen from the atmosphere like legumes.

Buckwheat makes an excellent green manure and adds nitrogen to the soil by turning it in as with any green manure. It does have a very agressive growth habit and will indeed choke out other plants (weeds). Buckwheat treatment after harvest is an excellent way to keep weeds from taking hold. Be really careful not to let it go to seed or it will become your new weed!


-- Oscar H. Will III (, March 06, 2002.

I had a plot for a few years with 4' wide black vinyl(not plastic) sheeting left down the entire growing season. Best thing I ever did for gardening. Kept it down with rocks and log spikes. Holes cut out for tomatoes, etc and slits cut for radishes and carrots. It worked great and only the pole beans didn't seem to do well with the higher soil temp, though still still produced ok. Everything else grew great, especially the tomatoes. This was up in PA where summer temps rarely went above 90. The vinyl lasted several seasons without degrading. I pulled it up every fall, tilled mulch in and left it off until planting time. Laid it right over any weeds that had already popped up. It's original purpose was used in underground communications lines to wrap around splices or something.

-- Dave (, March 06, 2002.

Another solution to growing season weeds may be to use scavenged carpet from floor covering business. This idea I read somewhere, I tried it twice, once during a hot dry summer. Had the best crops, corn potatoes, etc. with minimal watering. The carpeting, cut to fit between rows and tucked close to stalks held moisture and provided shelter for the toads, a gardener's friend.I stuffed straw in the gaps cause we had ragweed that wouldn't quit. At seasons end, you can roll them up after drying in the sun and store them in the shed for next year. This yr. I think I'll use it instead of the weed guard in the flower borders because mulch covers it well. Best wishes on your efforts, hope this gives you a solution.

-- Marjory (, March 06, 2002.

If you're going to use carpet, be careful. Quite a lot of them have bases which are heavily impregnated with pesticides. Not a worry for most people inside, because they're not touching the base. However, the pesticides will leach out in the garden when they're wet. Many organic operations who've tried what seemed like this good idea have lost their organic certification for several years. Even if you weren't going to be an organic operation, there can be a LOT of pesticide, and the types used may be unsuitable for and disapproved for use on food.

-- Don Armstrong (, March 07, 2002.

I do my tilling and planting as normal then put down two layers of newspaper everywhere except right over the plants, then cover with medium size/weight mulch. This keeps the weeds to a bare minimum except right around the plants themselves, so I have very little weeding to do during the growing season. I can usually get two seasons out of the mulch before I compost it, and the newspaper is tilled into the soil at the end of the summer.

Stacy in NY

-- Stacy (, March 07, 2002.

Stacy ,

Thanks for the idea. Right now I have the squares "super baking by using a green house tent over thye ground vinyl. The under vinyl temps are 170 plus today from the double greenhouse effect.

-- Jay Blair in N. AL (, March 07, 2002.

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