Solarization

[prairiegardens]

wondering if anyone has tried this and what sort of result they had? I had a bumper crop of weeds this fall and got most of them pulled and then the ground covered with straw for the winter, but the weeds had pretty much all gone to seed by the time it was all done, so the weed seeds will be flourishing next spring no doubt.

Im thinking to pull the straw aside next spring and cover the soil with clear plastic for a month or so, we always (almost always) get several glorious months of sun followed by a week of heavy frost in late May, so planting much before then is adventurous in any case, but I don't want to plant all those weed seeds by rototilling or whatever. The village council gets extremely restless even with the straw, so layers of cardboard and straw or hay are out. By the time they get organized enough too protest about the plastic it should be gone. 

I tried black plastic...used lumber tarps..but had mixed results with it, although it did restrict the weeds quite well it took a very long time to do so. Thinking that the clear plastic would cook anything trying to sprout...

opinions? Experiences? 

[reed]

I think the clear plastic works better. It lets in and traps more heat. A lot of weed seed will actually sprout then cook. Bury the edges to make a complete seal. I don't know that I would bother to remove the straw first, just let it rot and turn into soil. I recommend stuffing the village council under there too.

[steev]

I agree with reed; clear fries better, but I think you want to put the village council under a really big compost pile, cadaver dogs and all.

[jondear]

A flame weeder would kill that carpet of weeds effectively without chemicals. I've been thinking I want one, and apparently Farmers Friend has just put their version on the market. I saw it in action on a Curtis Stone video on YouTube. He and J.M Fortier are big proponents of stale seed beds; making things easier on the farmer by letting time do the work.

[billw]

Flame weeders will kill seedling weeds, but not the seeds, and not anything that regrows from the root. They are very useful in a very narrow range of circumstances. I like to use one in the spring when tuber crops haven't yet emerged. I can kill off all the germinating weeds without any risk to the tubers planted beneath. Once the crop emerges, the flame weeder gets put away until the next year.

As for solarizing, the only problem is that it kills everything in the soil, good or bad. I only do it when I am worried about disease being carried over.

[reed]

Oct 22, 2017 9:06:57 GMT -5 William said:

In my experience plastic mulches tend to eventually come apart and this defeats the purpose in my view of not gardening with chemicals. So the long duration of a solid mulch is a greater risk for this as is repeated reuse of the same plastic sheeting.

The problem in my view is that none of the above propane, roundup, or plastic sheeting are sustainable practices if we wanted to stop using fossil fuels and industrial chemistry reliant on them. As well as to stop polluting with CO2 micro plastics, and chemical break down products including the dioxins released when plastic burns. Which I for one do want to stop.

I haven't used plastic for years, it can work but has lots of drawbacks. For one, if it isn't the very expensive kind it degrades in UV and breaks into pieces that have to be cleaned up.  Flame weeders are about goofy in my opinion. No chance I'll be buying one or the fuel to run it. I do have a lot of cedar trees and a light covering of their branches allowed to dry out awhile and set ablaze is similar I suppose and I have done that. 

I never have and never intend to use roundup or any thing else. The only "treatment" that has been in my garden in the last twenty years is BT for cabbage worms and I'm trying to breed a brassica race that grows when it's too cold for the worms. 

I don't suffer from the O'my God a weed! syndrome anymore. Shovels, rakes, hoes and fingers is all that is really needed to tip the competitive balance in favor of the vegetables, at least I find that to be so. Pulled weeds also make fine mulch. When I first moved here and made the garden I had lots of thistles, horse weeds and Johnson grass, all of which made fine mulch when harvested at full size but before seeding.  I have thought about getting some patches started back up but now I got a big patch of sun chokes and I think the thinnings of them may be just as good. 

My point is, I think it's possible to grow lots of food without any help at all from lowes, monsanto or any of those other disgusting piles of excrement. 

[diane]

Oct 20, 2017 19:58:54 GMT -5 prairiegardens said:

the weeds had pretty much all gone to seed by the time it was all done 

It sounds as though you started in one corner and meticulously removed every weed. You can avoid reseeding by doing a quick all-over weeding. Just pull up the weeds that are about to flower, and ignore the others for the time being. You can then use one of those flat little hoes to scuffle the small weeds, or you can wait for the next lot to put up flower buds and pull them.

Don't let them drop seeds. 138 years ago Professor Beal of Michigan buried bottles of weed seeds which have been regularly dug up to see which seeds were still viable.
After 120 years, two species still germinated: moth mullein (Verbascum blattaria) and round-leafed mallow (Malva rotundifolia). In 2020 the next bottle is to be dug.

[tessie]

I attempted a solarization a few years back in a marine climate- not very warm and foggy. What really happened is the weeds sprouted like mad under the warmth of the plastic then died of thirst because the plastic prevented any water from getting to them. Wasn't planned but did give me a place with few weeds.

BTW I use cardboard and cover it with a shredded bark mulch. Looks like landscaped ground long enough for what's underneath to die. If done in the fall, it makes a wonderful bed for planting by spring.

[steev]

I don't mess with solarization; in my windy environment, keeping plastic in place is a PITA; at this time of year, (rainy-season coming, one hopes), I tend to rake off the dry weeds, forking them into the tree-lanes, or just covering them with a mulch of bunny-bedding, prior to tilling in the whole mess, come early Spring. It takes a couple tillings to trash the spring-sprouted weeds, but there it mostly is, and I'm good to go.

I use cardboard and bark, quarter-inch pebble, (not that gorilla-hair crap, which makes it awful to later get weeds out and it's itchy) when I'm xeriscaping a lawn.

[philagardener]

Cardboard is great stuff! I pull off all the tape and labels so they don't hang around for years and then cover with wood chips (of which there seems to be an endless supply in suburban areas.). I overlap openings/edges and it pretty much stops everything except bamboo and honey locust.

[prairiegardens]

Tried a flame and rapidly came to the conclusion it's designed to keep brick or concrete pathway cracks free of weeds, anything larger is simply impractical. I'm not buying plastic but reusing stuff destined for the dump in any case, same as lumber tarps, so I don't feel particularly guilty about using plastics if they work. RoundUp and such to me are about the same as spraying the produce with arsenic so they are not ever under consideration for a millisecond.

Part of the reason cardboard isn't being a viable option (other than the villlage council obnoxiousness) is I used newspaper several years ago and after three years uncomposted bits were still showing up, so cardboard would likely have a half life of 20 years, not an appealing thought. The persistent use of chemicals plus endless tilling before I got the lot seems to have a done a major assassination of earthworms and soil structure which is taking a while to restore itself.

Unless I get some sense of progress pretty soon I'll resort to raised beds and at least somewhat limit the amount of soil I'm trying to deal with. Wood chips are totally unavailable here..I would even use sawdust if I could get it but the only place within 50 miles that has any won't allow anyone to take any because of insurance issues allowing private vehicles into the yard. It gets discouraging sometimes, frankly.

[reed]

I have used cardboard a little and found it worked pretty well, decomposed OK. The reason I'm hesitant about it is cause of a stint I did in a Lowe's distribution center. The smells that came out of some of the shipping containers, sealed in China, was pretty unpleasant and distinctly chemical although I have no idea what chemical(s).

Our local grocery store bundles theirs and I have thought of using it, for the most part at least it's probably domestic but still, just cause it's for food I wouldn't be surprised if they don't spray it all with God knows what in the warehouses.

[Gianna]

Ive used cardboard under deep mulch to keep paths from growing anything. Not over the growing beds however - I just don't like the idea. Could be because it tends to be very dry here in the growing season.

As for solarization, I haven't used it on beds and doubt it's hot enough here for that (SoCal). But I have used it to freshen used potting mix. I grow a lot of things in containers and reuse mix, sometimes for years. Over time there can be too many weed seeds and various other undesirables so it needs 'rehabilitation'.

Ive done it several ways, but the most effective seems to be spreading the moist mix over a hard surface (not more than 2 inches deep), then covering it with 2 sheets of clear plastic. First, cover it with one sheet of clear plastic, then over that, putting something heat resistant such as wire or rack, to keep the second sheet of plastic from touching the first. Separation of the two sheets should be from 2 inches up to 6 inches. You are creating a solar oven effect. Tuck everything in and let the sun do its work. Temps in excess of 140*F are very easy to attain. I forget the number of hours needed. Once I set it up however, I usually leave it for a couple sunny days, which has been more than enough. It is rare for a viable weed seed to survive.

Since the mix I solarize is pretty old and a lot of the organic elements broken down, I then usually mix it 1:1 with coir. It works great.

[prairiegardens]

I hadn't heard of using two sheets but I like the results you got so may try that. Even so it may not solve the whole problem but it should help a lot . It's unlikely to do much for established thistle but should slow down the spread of both new thistle and pigweed at least.Thanks for the info on your technique.

[Gianna]

I had been thinking of making a frame for solarizing smaller patches of garden/paths where Bermuda grass is a problem. Just a smallish 2X4 frame, putting plastic directly over the weeds, and then another layer over the frame. Obviously this could only be used for small areas, and then moved. I decided however that it would not be more than a temporary fix because of the deep rhizomes of Bermuda grass. Solarization is not effective more than a couple inches or so. This might be effective for zapping weed seeds.

edit: It's not my idea - there was a YouTube video about reusing greenhouse mixes.