Warming up the beds

Has anyone used black trash bags over their beds to warm the soil? Does it work? Right now the beds are still frozen, of course. But it's going to be in the 40's today, and I was thinking about trying it as I'd like to start lettuce, etc ASAP!

I can't stand it anymore, so I'm starting pansies in the house today. I figure I can put lettuce in a pot before long. Then it can be moved onto the deck as weather permits. I know by March the pansies are normally fine outside. Can't wait!!

Nancy

I've used brown pastic to warm up beds in early spring for summer crops and it works so I'd think using black trash bags can't be much different.

Nancy - I was thinking the SAME thing! It's also going to be in the 40s here in NJ - Its like a warm snap compared to what its been. In fact I'm going to head out there now and do that on my 2 table top beds. Those are the only beds that are ready right now.

I know a lady in Beckley, WV who uses black plastic as a mulch for absolutely EVERYTHING. I can't argue with her success, but I'd be worried there'd be too much moisture retention in a square foot garden (she uses in ground gardening). She has the greatest yield in almost everything she grows. If, and when, I get enough blocks, I might try one with the plastic.

I read an article in a garden magazine the said while black plastic was good, clear plastic was even better. Dark colours attract the heat and helps warm the ground up quicker. Apparently, according to their experiment, the dark plastic heated up which did help the ground underneath to get warmer. However, the clear plastic over the ground actually allowed the GROUND to attract the heat, rather than just the plastic, then trapped the heat so it actually worked faster.

Since then, I have always used clear. But if black is what you have, it will definitely help.

Gwynn

As for the colors, I used the brown plastic mainly to help deter weed growth besides helping to warm the soil and keep it dry from the heavy rains. The soil warmed up a bit, but not as much as my clear plastic beds.

I have to admit I didn't like the dry feel of the soil just under the plastic itself. This year I will be more conservative with the brown plastic.

As for warming up the soil, the clear plastic I put over my raised beds in the spring did a lot better. The clear does not deter weeds but as a warming factor, its A+ in my book.

These were some of my beds with clear plastic last Mar 18th. Unfortunately this year my beds are still under over a foot of snow. Ugh. I don't know when I'll be able to cover them with clear plastic.

Eliot Coleman did a test on this very thing. He used several different things but the clear plastic won the temperature rating at approx 8-10* warmer than the uncovered soil.

The fact that it does not deter the weeds is the down side of using the clear plastic. However, I have read that the good thing about that is that the weed seeds start growing sooner and have then expended their energy before you put your seeds and seedlings in. It does seem to work like that in my tomato bed.

The soil does get very dry because it sheds the rain so you do have to add water. Once you do that though, the plastic tends to keep it from evaporating so fast. Like lots of other things in the garden it is a bit of a balancing act but I do find the positives outweigh the negatives.

Gwynn