The only problem with the black plastic is that it does not break down. I used it and have it surfacing all the time, and I put it down about 12 years ago! I'd rather use newspaper. It breaks down and if you decide you want to move a plant or add any to your flowerbed you won't have to cut holes in the plastic just dig through the paper.

Dapper, you are talking about weed control for your dahlias, are you not? The black plastic mulch isn't what you want to be using for these. There is just no way around weeding and hoeing. It is one of the joys of growing dahlias. Most of the growers we know who grow dahlias do the hoeing routine. And, most of us feel it is good soil aeration and good for the plants. Just think about all those beautiful flowers you are going to have........

I'm a one-woman campaign on this pitch, but I truly believe that the best way to avoid weeds is to bring in the best planting mix you can find from a local landscapers' supply by the cubic yard, a mix with rice hulls, lava rock, sand & manure in it, and form it into raised planting berms--instead of amending existing soil. Less backbreaking work, more planting fun, & when weeds do appear, they come out easily. I put shredded cedar or redwood mulch around plants after planting, which further discourages weeds. On my garden's floor, I did install high quality weedcloth--not plastic--which is also covered by shredded cedar. When weeds emerge, even now, after 2-3 years, they're individuals, and pull up easily. I don't even have a hoe!

Many resist the expense--good soil can be $30-40 a cubic yard, but in the long haul, the cost-benefit ratio makes it well worth it IMHO!

Karen

Hey thats great karen but i have 3 chicken barns FULL of chicken manure and great soil to put it on because of being on a farm and the soil being kept in good condition i havent had any problems but that sounds AWESOME if I only had money and not so great soil! When i get married and move i'll remeber that for my flower beds :o)

DapperDahlia - were you planning to use the plastic weedcloth in the beds or as paths? I use the heavy weight Dewitt weedcloth for my paths (2' wide) and am starting to plant all my perennials through a lighter weight weedcloth that I ordered from Dalon products (their products are at Wal-Mart). I am putting good quality compost under the weedcloth. (oh and this weedcloth is not "plastic" - it is woven and permeable)

I did NOT plant my dahlias through weedcloth because you never know exactly where they'll pop up! So, I'll be weeding them by hand!

I am also testing with the lighter weight weedcloth in some limited annual plugs (strawflowers, snaps, larkspur, gomphrena, dianthus, and tithonia). I'll report on my success at the end of the year!! This method in the annual beds requires lots and lots of staples (because my beds aren't perfectly flat, are on a hillside, and its always windy and the plugs are little - so the staples are about 12-18" apart in the beds holding the plastic down.)

Good luck,
Wendy

Whoops, Dapper! I'm glad you filled me in on your setup. Clearly, while my plan has redeeming virtues for small to medium gardens, in your situation, I can see it doesn't make a lot of sense. I have found, however, that shredded cedar or redwood on top of the soil around plantings reduces weeds &/or makes them easier to pull up, but I don't know if that would work in your world.

Karen

Karen, I don't make enough money with my flowers to afford that much good dirt! The idea is for the flowers to pay for themselves and a little profit, not to have to subsidize my growing habit with money from elsewhere. And I live so far out in the middle of nowhere, having ANYTHING trucked out here costs $200 minimum, just for the trucking, NOT including the stuff I'm buying. I have to agree that your system is great - but not practical in the amounts I need.

I use a woven black weed-control/landscape fabric in my perennial beds, but don't think it's cost/time effective for annuals. In this climate, anything that warms the soil up is a dynamite idea, so black plastic or fabric works out well. Bark or anything on top of it defeats half its purpose (warming the soil up) here. For annuals, I till thoroughly first, then pull/hoe as needed, just enough to keep the weeds from setting seed or drowning my plants. I till it again as soon as the annuals are finished. I've found this keeps the weeds down somewhat, and I don't have all that trashed black plastic to deal with.

Jeanne

All, I have used pro-witt 5 on my perennials and trees with about 3 inches of bark on top (pro witt 5 is $198 for 6' x 250'). On annuals the best is 6 mil black plastic (no bark on top)(Black plastic 6 mil was $98 for 40' x 100'). I have been doing that 7 years and it works great for me.

I did just bring in 15 yards of compost for $450. All of that is going in the growing beds in the greenhouse and new lily area.

Newspaper or other items would work on a small scale. My acre would be too time consuming and kill me.

Bryan

Black plastic is a nuisance to dispose of. And the plastic has a tendency to interfere with soil aeration. This is going to be a problem with your dahlias. Good soil aeration makes for happy plants. Supression of weeds with compost, peanut shells, pine straw would be ideal. However, growers who follow conventional farming practices can obtain very good weed control in some flower crops (dahlias) by using pre-emergent herbicides. They are sprayed on the surface of the ground and incorporated into the upper layers by either tillage or irrigation. They bind to seeds and prevent seed germination. The pre-emergent herbicide, Treflan, is registered for use on flower crops. It only works for control of annual weeds. Subterranean, perennial weeds require chemical control. Certain tough, perennial weeds that spread by underground rhizomes must be controlled chemically. These include nutgrass, Bermuda grass, and bindweed. Attempts to control these mechanically (hand-weeding, hoeing and cultivating) are almost certain to fail. Chemical controls have justifiably received a bad name because highly toxic compounds have been sloppily and inappropriately used, and sometimes still are. However, some cutflower growers do use Roundup for control of perennial weeds. A contact herbicide similar to glyphos (Roundup) in its mode of use but acceptable to organic farming practices is a solution of potassium salts of fatty acids sold as Safer Sharpshooter.' It is expensive; and, it has no particular benefit in either weed control or environmental safety. Another good method is to attempt to outcompete weeds with cover crops or green manure crops. An advantage is that these crops outcompete weeds as well as adding organic matter to the soil. One has to be diligent about letting these crops go to seed or they will become the weeds you'll be battling next season and beyond.