You know, it was bound to happen. I put in alot of effort and the Sun takes a vacation. I have several beds that need alot of attention. They need to be dug up and amended and re-planted. The first step is to try a weed control called "solarization". These beds are over run with WEEDS. So I cleared a bed that was the worst performer (poor iris growth and major iris loss) and laid down the plastic. I went the cheap, do it now with what I got method rather than the right materials because of time and cost. I am using "regular 4 mil "construction" plastic rather than the UV-inhibitor type because I already had a roll and did not want to travel the hour to get the right stuff (forget the fact that the right stuff would have cost about $100 plus the gas to get there and back).

The other crappy issue is that the Sun has decided to take a vacation. It has been very sunny and very warm (upper 80's and lower 90's) for the last two weeks. The next 10 days are going to be cloudy and cool. Timing is everything and I am waaaaay off! Oh well. I am going to leave it in place for about two weeks and them do another bed. This could be interesting.






Did I know about the weather change? No. But I do now. I was awaken this morning at 3:16AM by the bad thunderstorm and then I drove through it on the way to work. Just looked up the 10 forecast. Lots of clouds and a fair amount of rain (no complaints in that I need the rain as my ground is very dry).

Again; timing is everything!

I'm going to have to try this, as well. I have read so many good things about solarization. Did you put on any amendments first or did you put it down over the "weedy" beds?

No amendments were added though I could have used a bit more dirt in the bed. I cleaned the bed well as the first picture will attest to. You would need to till a weedy bed as this will not work well on a bed that was not prepped.

Clear or translucent plastic creates a greenhouse for weeds. Black plastic creates a solar collector that bakes weeds. Buy black plastic or get big black trash bags (you can reuse later) and lay them over the plastic, weighted with rocks or something.

Good idea Linnea. I had not thought of black trash bags as they are fragile. However, laying them over the tougher plastic and weighing them with stones would work. And, like you said perhaps I could re-use them later and if the sun had weakened them to the point to make them useless it would be no great loss.

I have been solarizing for years. Mostly in the veggie garden though. First off, you can do it with cheap farm tarps. (get them at tractor supply, or Farm and Fleet stores) I get the kind that are black on one side and silver on the other, the largest of these is less then $50. I put the black side up. I hold them down by putting short cheap electric fence step in posts through the grommet holes. The idea is that the black tarp collects heat. It doesn't allow the moisture to escape so you have a worm moist area where the weed seeds try to germinate and die for lack of light. If light gets through, the weeds can grow under it, kind of like a terrarium. If you have enough time (like doing it early in the spring until late fall or the next spring) then you can just spread your compost on top of the soil, and the worms and insects will break it down and mix it into the soil for you. You won't have to till or work the soil at all before planting. Before I stole a bunch of my veggie garden for irises, I used to plant half of the garden, and solarize the other half, then switch every other year. It was amazing how few weeds you have to deal with then. I'm solarizing a new area right now to use as a veggie garden so I have more space to rotate crops to avoid blight. (Also as I keep making seedlings, I'm going to have to take up even more of the veggie garden space.) To get the most benefit from it, you need to let it solarize for several months at least. I'd recommend solarizing areas now that you want to plant next year. It's a great "No chemical" way to get a bed ready.

Clear plastic will do the job fine. I would say better than black plastic as more of the Sun's energy will pass through and bake the ground whereas the back will absorb more energy. I am using the same method that Rick & Roger use at Superstition Iris Gardens but on a much smaller scale (and smaller time scale too!).

I wish I had the California Sun as this method works fine out there. Not sure what results I will get with less Sun, maybe less intensity, and slightly lower temps. I wish I had the space to switch back and forth from bed to bed like they do at Superstition. Just don't have the room. Could it be that I have too many irises?

Nah, can't be right?

Oh surely not.......................

Misawa77 said:Could it be that I have too many irises?

Is that even possible?

You can never have too many irises! You can have not enough space, not enough $, not enough time but never too many irises!

For a small space, I used an old plastic tablecloth. I left it for 7-8 weeks and it killed the grass and weeds.

This one will only be on for a short time. I intended to put it out around July 4th and then change to the next bed 20-25 days later. I may get 15 days on this one. Who knows.

Oh duh. I read you had limited time. I should know better. Coffee first, THEN post.

Run out of room? You have that whole front yard empty of iris!!!

I've talked about this before. I was given a command to remove all of the irises from the front yard. I can not go back.

Greg, I do believe you're right about clear plastic. Down here it is necessary to solarize the soil regularly for nematodes. All the commercial farmers must do it so it's well documented. Clear plastic is the recommended stuff, for most heat generation as long as you seal the edges down well. But I can tell you from experience, the cheap stuff disintegrates very fast in good sun. Six weeks is also the normal timing, best started in early June to take advantage of the hottest sun.

Obviously, black also works as Tom's experience shows but not as well. Think of a closed unventilated greenhouse in the blazing sun all day.

The reason I use black is because I am re-purposing the tarps that I use to cover hay. However, I did use a blue one that I bought for the purpose of using as a mulch as it was cheaper. It does allow some sun through it, and some weeds still grow under it. I also use it as a mulch in my veggie garden. It virtually eliminates weeding.

I wonder if clear is better for hot or sunnier regions? I'd tried that once but just got a jungle of weeds under the plastic, even in the hottest part of summer. I have had good luck with black though...

I think since our earth is moist, and we do have a lot of underground water, that the clear just makes a hot, hot greenhouse. The moisture gathers under it so that you cant see through it and the weeds do live in that hot moist atmosphere. When I take care of pesky hard to manage weeds I use boiling water and sometimes that just kills the tops and they come back from the roots. I guess our weeds like it hot. The black plastic makes it a lot hotter but it has to be on for a long period of time before it kills the weeds.