Solarizing

Now is the perfect time to solarize empty plots or create new ones. Non-toxic way to kill weeds, grass
and some destructive leftover critters.

First pic is a 2 x 8 bed I had covered with old storm windows to make a HOT bed about a month ago.

2nd pic is closeup.

3rd pic is new system installed today. 6 mil clear plastic held down with small pieces of
wood tacked with a brad nail gun. For best results, the plastic needs to be sealed in order
to keep in the moisture and heat. Also, if the soil is dry, water should be sprayed on the
soil or grass before the plastic is laid to create the hot steam effect.

The hotter the direct sun, the quicker the grass will be killed along with some grubs and
borer pupae. The sun needs to be nearly directly overhead for the best results.

How long will it take, need to make a couple more beds and the old rotortiller is out to kill me.

Oldgardenhorse, please tell me what "hot bed" means? I think I know but not sure.

Thanks' confussedlady

Up early again. Will be another warm day again judging from the ac running at 0430. Get
all outside chores done by 1000.

"Hot bed" is an old term we used to raise melon plants in April to be set in the fields by first
week of May. Here I used it to mean a really hot method of killing grass. I have done it by
just placing the storm windows flat on the grass with the edges butted against each other.
Leaves an small strip of green where the metal trim shades the grass but they can be moved
slightly to overlap the strips.

As far as time required, a week of hot, direct sun will kill the grass leaves but will leave
green stems etc near the ground when a 4 to 6 inch raised bed frame is covered with either
glass or clear plastic. I would plan toward 3 weeks to completely kill the surface grass and
some of the roots. It is important to seal the edges of the plastic, with soil on a flat plot or
staples on a wooden raised bed, to let the system operate efficiently. I checked one of mine
last year with a cooking thermometer and the temp was 130 to 140 degrees in the early
afternoon.

The plastic is available at most hardware outlets. I bought the contractors box of 10' by
100' roll of the heaviest they had--6 mil. Cost about $60 but it will cover a lot of bed area.
Only the clear will work. Black only gets hot itself and shades the ground.

Again, it will only work well in direct sun during mid June to late July in my area. Other
parts of the country would be adjusted according to the normal weather.

At other places where I've lived, I've used a black swimming pool cover, and a brown tarp for this purpose. I tried using a blue tarp and the sunshine still must get in because it didn't work.

Thank you for bringing this up again. I have an area that I wanted to do this with, one that I needed to start over with and this will work perfect. I couldn't remember if it was the clear plastic or the dark. Thanks.
Laura

I am so glad that you startet this thread because just yesterday I talked my husband in to putting up an older woodenfence which was given to me by our oldest son when they moved .He also bought me a truckload of topsoil to make irisbeds ( the iris 'bug' has bitten me badly )

I have mentioned to him that we had to put plastic down to kill the grass,he didn't think it was neccesary since I am going to do the bed about 8 inches high.

Will let him read this when he gets back.

What are your thoughts ?

mare200: The sun shining thru the plastic to the soil is what creates the heat on the ground.
The plastic is to trap the heat and not let it escape. Works just like solar heat. Usually, the
black or dark material will stunt the grass or weeds and make them turn white for lack of
sunlight but does not really kill them.

The 8 inch depth would probably keep the grass down for awhile but may come up thru the
soil later. I have some that grew up along the inside margins of my temp beds where the
sunlight did not create enough heat due to the shade. If you have time, go with the plastic
for another reason. All of the common gardening soil, including the potting soil and what is
marketed as 100% humus in my area, is nothing but a mix of dirt, sand, leaves and wood
stirred together. It has a lot of weed and grass seeds plus probably a generous dose of
Lord only knows diseases. The recommended method is solarize the new bed after all
the soils and admendments are in place. The new bed needs to settle for awhile anyway
so that would be a good time to soak it well and cover it with the clear plastic.

Tilling the grass under just chops it into another hundred pieces and spreads it around.

Each area may have slightly different heating conditions but the solarizing principle is the
same. From what is on the tv weather, you Texas people need to just stand by. Mother
Nature will kill your grass for you.

Last year I covered a raised bet that was full of grass with white plastic for about 6 weeks and it wasn't all dead, so then I covered it with black plastic for about 6 weeks and it still wasn't all dead, So then I covered it with cardboard and put rocks on it and let it sit all winter. That did it. This spring the grass and weeds were gone.

In this dry hot part of Texas, I have had wonderful success with laying down cardboard, laying landscaping timbers around it in the shape I want and waiting about 6-9 months. Without grass killer chemicals, the bermuda grass is dead -- roots and all! I can pull off the cardboard, water the area, and turn the dead grass/soil over with my shovel. I can add compost, till the soil a bit more, and the iris is bed is ready. I am not sure this would work in other climates but it works for me. I am so glad to know about the clear plastic option which would work here I think and definitely work faster.

Also, wide strips of card board (thanks to pizza boxes) under landscaping timbers, along with a little grass killer, has proven to be a good bermuda grass barrier around the iris bed. Bermuda grass is the bane of my gardening efforts.

I use newspaper placed on the ground about 8 to 10 sheets thick and cover it with 3 to 4
inches of mulch in places where there will be no plants such as around trees and borders.
Does a good job of keeping weeds and grass from coming up thru the mulch and recycles
itself.

Added: In pic 3, the left side of the bed where the extra flap of plastic is lying over the bed,
I went out before noon to trim it and all the sweet clover under it was brown and crispy. That
would have been 24 hours without being sealed down. I could feel the heat when I raised it
to trim the excess.

This message was edited Jun 26, 2009 7:16 PM

This is my main iris bed where all the modern irises were grown. Dug and disposed of them
and put the plastic down after watering the very dry soil. Pegged the plastic about each 6
feet and sealed the edges with soil. For a sizeable sheet as this, I recommend pegging at
least a cross L x W at 4 to 6 feet intervals to prevent the wind from raising the plastic and
tearing it loose.

These are Dupont biodegradable pegs sold at garden centers. About 3 inches long and
holds into the soil if it is not too loose. As far as the plastic installation, do not stretch it
too tightly during hot weather. It will shrink when the weather chills.

I have a concrete stone look walkway that gets filled with weeds each spring. I spend all summer trying to remove the weeds to keep the pathway attractive. I tried laying a sheet of glass directly on the walkway. It seems to be working. Thank you so much for the info.

The glass is more effective than the plastic because it is really clear where the "clear" plastic
is slightly milky. We replaced all our windows last summer and I kept a few panes of the
storm windows. I could kick myself for not saving all of them.

Glad the process worked for you. Sometimes imagination beats effort.

Another idea for keeping the weeds between stones down is to plant plants such as thyme or veronica inbetween them. They keep the weeds out. I once saw a picture of a very fancy house with a beautiful flagstone patio with thyme planted between the stones. The builder had even put a drip irrigation system under the stones to keep the thyme alive. The picture showed the thyme blooming. It was gorgeous.

What variety of thyme. Could I just sprinkle thyme seeds between the stones?

Any of the ones listed here:

http://www.highcountrygardens.com/catalog/search/products/?query=thyme&x=37&y=13

I would suggest starting with a few plants until you see how they do for you. Then if they survive for a year, buy seed and start it indoors or winter sow it in pots and then place it where you want it. You might try sprinkling some seed between stones. It just depends on your climate. I don't know whether it would work here, but your climate is a lot wetter. Thyme and veronica are widely used here between stones and in rock gardens. BTW, High Country Gardens isn't the only place to get these, but they have the best desplay I know of .