I thought it was just my bad luck! I used it two years ago and raised a bumper crop (no kidding, huge bumps!) of oxalis underneath. Never used it again--wish mine had been porous like the newer stuff.

If I were going to use it again, I'd lay down the black weed-block fabric first. Seems silly, but I bet it would work and probably not hurt.

They should make this stuff with one red side to reflect the desirable light waves back up on the tomato plants, and one black side to cut off any light to plants growing beneath the sheeting. Dat's what I think!

Weeds under the mulch can't be pollinated so they can't set seed, can they? They can sprout but they will die back eventually. At least they did under my brown plastic mulch.

I'm in Sacramento too, and I can't advise you to just go with the advice that "they'll just die back because they can't set seed. That might work somewhere else (especially in cooler climates), but at least in my garden the most persistant weeds have been nutsedge and bermuda grass, and neither needs to set seeds to be a serious problem. They're perennial weeds that spread from tubers/stolns. What's more, if you succeed in getting rid of everything that DOES need to set seed, then what you have left is a bumper crop of the perennial weeds that are hardest to eradicate.

Under soft mulches made of organic materials, weeds are usually easier to ull than they are in unmulches soil.
I'm not sure what the answer is to weeds under plastic mulch... I've never used it. I have to say that I DON'T recommend just leaving them, though. They're taking nutrients from your plants and competing with your garden plants for root space. They need to be removed somehow.

Blogger is down right now (uggg.) but my blog post today is on nutsedge, my current worst garden weed.

Here is a link that might be useful: my blog

In addition to not setting seed, plants trapped under mulch also can't breath properly, and get overheated by the sun while having beads of trapped water held against their leaves as they are pressed to the ground. I used IRT last year and when I pulled it off, the only living weeds were under the openings in the plastic. The rest was completely bare ground.

But maybe it's different in other climates with other plants and other colors of plastic mulches.

FWIW, I found some research wrt nutsedge and IRT mulch. Raymondo, it really makes sense to identify which weeds you are dealing with and base your actions on that. It turns out that yellow nutsedge is actually supressed better by IRT than it is by opaque mulch. It's a big problem in crops mulched with black plastic be4cause it actually penetrates the plastic and grows straight through it. It seems like a black-backed red mulch would actually be worse than the translucent red stuff if you're dealing with same weeds I have.

I'll include the link to the IRT/nutsedge paper. It's usually possible to find similar research for each weed species you might be dealing with. Use the terms "weed science" or "IPM" plus the weed name and IRT mulch.

Here is a link that might be useful: irt/nutsedge

Well howdy, neighbor! Lunita, a pleasure to connect with someone in the same gardening region. :) I checked out your blog and I'm sure it'll be a staple of my morning reading from now on.

>...but at least in my garden the most persistant weeds have been nutsedge and bermuda grassInteresting, nutsedge is a very rare weed in my garden. But bermuda grass... don't get me started! My neighbor's unkept property is a bermuda grass farm, and it relentlessly attempts to migrate into my garden. Grrrr! It's a constant battle. And like Steve, I had an Oxalis issue in my lawn last year, but I strayed from my organic gardening methods and found a spray that knocked it out beautifully.

Happyday, you should see the size of the weeds that survive under that red plastic. I'd go so far as to say they thrive under there!

And Lunita, that's a good idea to identify the weed that's the primary issue in my tomato beds. I'll take a photo today and post it, see if anyone can help me identify the culprit.

Raymondo, where do you buy your red plastic? Are all red plastic mulches the same?

Anybody recognize this weed?

Here is a link that might be useful: {{gwi:54379}}

>Raymondo, where do you buy your red plastic? Are all red plastic mulches the same?I can't answer whether all plastic mulches are the same, as I've only tried this one. I can tell you where I bought the mulch, and that was Gardener's Supply Company. A link to their red mulch page is below.

Cracks me up, but some of the reviews of the red mulch on the aforementioned site rave about the weed control. Well, with this particular weed, not so much. :/

Here is a link that might be useful: Gardener's Supply Company Red Mulch

Your red mulch must be too translucent. It's letting too much light through to grow weeds, and if you put black plastic or cardboard underneath, to suppress weeds, maybe the red would not be as obvious. Unless you put white mulch underneath, then maybe the red color would pop even more.

my best guess is dallisgrass -- it grows huge clumps, infests most lawns in older neighborhoods in our town, and grows from root pieces. It could also be crabgrass... I'd have to see the seed heads to be sure.
http://www.ipm.ucdavis.edu/PMG/PESTNOTES/pn7491.html (dallisgrass)

http://www.ipm.ucdavis.edu/PMG/PESTNOTES/pn7456.html (crabgrass)

Lunita, thank you. I don't know why I didn't recognize it, but I do believe my weeds are crabgrass. I've been doing battle with them in my lawn, where I usually don't notice them as such young seedlings.

It's very interesting to me to see how the red mulch affects these crabgrass seedlings. They grow like wildfire under the red mulch, but I hardly see any in the adjacent growing beds.

I wonder why red mulch is needed in Sacratomato, one of the best - if not THE best - tomato growing region in the country. Why consume a product you don't need!?!?

Dan (ex-Town and Country resident)

>I wonder why red mulch is needed in Sacratomato, one of the best - if not THE best - tomato growing region in the country. Why consume a product you don't need!?!?Because it turns growing conditions from very good to GREAT, that's why. I certainly notice an improvement in the vigor and productivity of the plants using red mulch.

The benefit of any plastic mulch is the soil temp and moisture retention. You can use anything similar for free and get similar results, without pulling out your wallet. Apologies for not making this clear (I understood myself perfectly ;o) ).

Dan

I have all my tomatoes under olive brown IRT, but will put red mulch under some of them, on top of the IRT, and see if there is any difference this year.

Dan, supposedly the color of the material is what makes the magic happen. Supposedly red light waves and "far red" light waves are reflected back on the plant, having a positive affect on its growth and productivity. I haven't personally performed any scientific comparisons of red vs. any other color, but I do know that my 'matas seem to be happier with this mulch in place.

Happyday, I'd love to hear the results of your test. Do report back! If I had just a little more space in my small garden, I'd do some comparisons of my own.

Raymondo, I'm also growing legumes and alliums right next to each other, so far no problems. Every year a new experiment. I'll post back when I learn more about the tomatoes response to the color red. I read that they have photocells which act as "chemical eyes" which react to the color, if I am saying that right. I also read that squash and melons perform better over blue mulch so may try planting them over purple mulch, which is the only other color I have.

Dan, supposedly the color of the material is what makes the magic happen. Supposedly red light waves and "far red" light waves are reflected back on the plant, having a positive affect on its growth and productivity.

AIUI, Raymondo, the current state of the empirical research is that it is the plastic itself and not the color - similar results across colors.

Dan

Do compare the seed heads of crabgrass and dallisgrass, Raymondo. For years I've thought I had crabgrass in my lawn and it was Dallisgrass, which is actually a lot worse. It doesn't die back in the winter (crabgrass in an annual, so if you have those thick bladed clumps alive and growing in your lawn all year, that's probably dallisgrass), and it is very drought tolerant. It sprouts from root pieces, so the seedlings are very vigorous (and wouldn't be killed if you tilled an area that had them already growing... they'd just be multiplied.)

My backyard was essentially a blend of dallisgrass, bermudagrass and nutsedge when we bought the house. Lovely...

According to the Territorial Seed Co. (which catalog also offers red plastic mulch--but no holes in theirs so I had to punch my own....), research by USDA and Clemson U. showed an increase in production of from 12-20% in early tomatoes compared to black mulch. Technically known as SRM-Red mulch. Strawberries apparently benefit also.

I live in a very difficult area for tomatoes, beset by summer marine fog, and I have to say that the red mulch didn't do much for me--except to grow bumper crops of oxalis underneath.

What does help (not surprisingly) is finding the warmest spot in my yard, using black plastic to warm the soil and carefully trimming off diseased leaves as soon as I spot them--oh, and choosing very "early" varieties.

I live 100 mi N of Sacto and those weeds look like what I have been fighting-Johnson grass. It dies back in the winter but if I dig it up I find large roots. If only a small piece gets left behind, it will sprout. It is sorta like bermuda grass on steroids. For the last few years I have been covering my garden with black plastic and have finally reached the point where most of my garden is weed free. My tomato plants were over 6 feet tall last year and I had so many tomatoes that I was giving them away to everyone.

Put some cardboard under it.

>Put some cardboard under it.Now why didn't I think of that? A fine idea, snoggerboy. Thanks.