Well that would depend largely on whether the plastic was left on for the whole year. If it was, I would say take it off and cover with something permeable like straw, leaves, grass clippings, all of the above. The chief problem with plastic mulch is that it reduces oxygen penetration into the soil and promotes that growth of anarobic bacteria and fungus. These can lead to a destabilization of the soil food web, promoting disease, reducing nutrition and leaching micronutrients.

That being said, having bare soil exposed to the harsh winter elements and shoulder season rains is not a good idea either. I would say that you should have taken the plastic off at the end of the summer and allowed your soil to rehabilitate before covering with a permeable mulch for the winter. However, sometimes something that seems like a silver bullet turns out to be a blank.

I have about 1/2 an acre under black plastic that is NOT covered with mulch, plus a lot of beds with plastic and mulch on top (those are for perennials and fruit trees, bushes, etc.).

I put mine down and leave it down for the roughly 3 years it lasts. It's too expensive and too much work to take it up every season.

I try to remove it in the fall that third year, sow winter rye for a cover crop, then amend the soil, till deeply and so forth the next spring before putting the new plastic down.

It does get more tears and holes each seaon, from planting and from accidents.

I don't see any loss of fertility in my soil or any other issues that diminish my garden's ability to grow and perform well.

Now, this last time, on part of my garden, I actually put the new plastic down right over the old, without doing what I described above. This was last spring, in March. We'll see what that does. I have some long-term concerns about that, don't know if I'd do that again or not, but it was a lot easier, and it makes a thicker barrier for the weeds.

Before I put my plastic down, I take a power drill with a long bit, about 1/8th inch diameter, and drill holes through the entire roll right to the cardboard tube in the center, about every two inches. This only takes about 10 minutes to do a whole roll, and results in nice, evenly spaced holes for water to pass through, yet they are small enough weeds hardly ever come up in those holes.

denis- I've previously taken mental note of your oh-so-smarty-pants drill method with the roll :) DH gave me a hollow aluminum post about 3/4" diameter after-the-fact, and I poked my holes that way...yeah, ended up with a few weeds in 'em, but not many.
And now I like your idea of putting new-over-old (which would solve my current problem of what to do with holes that I won't use because I'm rotating stuff that was wide-spaced, and now need smaller/closer-spaced holes...I might put 'thinner' ml over those sections w/duct tape.)

Not sure I understand the whole "bare dirt can't withstand winter" commentary, so you'll have to idiot-proof that for me :)

As far as anaerobic stinkies, I did have that but only on one section- the squash. Not sure if it was because they were sparsely planted and there was too much BP still covering the soil, or something else. It didn't happen in other areas where there were more or many more planting holes (corn, melons, tomatoes, etc).

Oh, and while I'm here, can I use BP with strawberries, or no? I'd like to 'control' those little suckers so they can't just take over the rest of the garden (ok, you can stop laughing now).

Strawberries -- I cut out the size I want the finished row to be. The runners that grow out over the plastic don't root in, and die over winter. So, if you want a three foot wide row, cut out a three foot section for them.

I think the poster who commented on leaving the soil bare for the winter is talking about issues like erosion due to water and wind action. I went to school at Michigan State, and I've seen some pretty good dust clouds blow up from fallow fields at certain times of the year. Can happen in winter under the right conditions -- dry soil, no snow cover, windy.

If you leave the plastic on all the time how do you ever do the necessary soil improvement or add amendments? I don't understand how you could expect to use the same soil over and over again without at least annual amendments.

Is the plastic just for a neat appearance? For weed control? Organic mulch can accomplish the same things while improving the soil at the same time.

For the most part, the only thing it'll hurt is the life-span of the plastic.

Leaving soil exposed to the elements during the winter causes quite a few problems in fact. First, erosion due to the melting snow and/or heavy fall and spring rains. The surface 2-4 inches of your soil contains the majority of the nutrients that a plant is able to access. Once that gets washed away, you are left with various degrees of subsoils.

Secondly, the constant freezing and thawing experienced in the shoulders of winter (i.e. early winter, early spring) will cause a great deal of compaction. This will eliminate all of the work you did trying to get that soil nice and fluffy.

Third, in the late fall a great deal of soil organisms and microbes (including most significantly worms) can get caught in an early, heavy freeze. Without some form of insulation on the surface, they will die quickly before being able to burrow further into the soil. Now you may say "so what, there's lots of them", but if the weather warms up after a freeze, the same thing is going to happen again, and again. The bottom line is that there are only so many worms in the soil.

Plastic mulches may assist in the first point about erosion, but it provides very little insulation against harsh weather. During the dead of winter, with or without a snow cover, it doesn't really matter: things are going to be frozen solid. It is the ability of a thick covering mulch to moderate the freezing and thawing during the shoulder seasons that is important.

Black plastic is a good idea but I would suggest a winter garden cover crop. This will help renew your soil and protect it at the same time.

Winter rye is one of the most popular crops. It's perfect because it continues to grow during warmer days in the winter. An annual grass that grows to about 1 foot tall by spring, it doesn't need good soil or much water.

But isn't it too late to plant a cover crop? (I'm in NH, and the weather is about to shift ANNNYYY minute now.

Erosion: Not an issue. I've never seen my garden areas get washed away. The ground is level. The snow falls, and melts. In the same place. The surrounding grassy areas are never 'extra dirty' with soil that may have washed out of the garden.
Freeze/thaw cycles and fluffy soil: It gets tilled again in the spring at least twice before planting.
Worm population: I seriously don't see this as a problem. At least not where I live.
Amending the soil: This is the first year I've used the BP. The entire garden was tilled under this weekend- yep, weeds & all. There was a lot of bolted lettuce/beets/spinach, etc...celery that never developed, some onions that I forgot to take in the house after I cured them, and a patch of failed cabbage. In the spring, several bucket-loads of compost from a nearby pile are tossed on the area and tilled in. This amending thing is my main concern; I have excellent soil due to this constant replenishing & it being on the site of a previously working farm (orchard, cow corn, hay, etc have all been at this particular spot).

I think I might end up pulling it back anyway; I don't have the coverage that dennis has, so it's not a huge area to re-work, but I do want the amendments done.

Hey, Dennis- how do you handle rotation of crops & holes in your BP? With the new plastic?

You asked: "Hey, Dennis- how do you handle rotation of crops & holes in your BP? With the new plastic?"

Well, the best I can. I try to put things into holes that seem appropriately spaced, so that I don't have to make new holes, but that doesn't always work out. Some holes end up being unused in future years, so they sometimes sprout a few weeds that require a bit of hand weeding. But, that is still nothing compared to keeping the whole space weeded.

You can still plant winter rye where you are. If it doesn't germinate this fall, it will come up first thing in the spring, assuming birds don't eat the seed over the winter. That way, you'll still get green manure next spring -- this stuff grows amazingly fast as soon as the weather breaks in the spring -- I've seen it shoot up a foot in under a week during an April warm spell.

Here in CA, if I don't keep the soil covered, it gets full of weeds. I am an older gardener with arthritis. I leave the plastic down all year around. Every spring, I fold back the plastic covering each individual 4'row and add horse manure to the soil. Then I put the plastic back and cover with grass clippings to keep the sun from degrading the plastic. I have the paths covered with chipped wood I get for free. It is more trouble to cut the plastic so that I can do each bed separately, but it works for me. If it has too many holes or tears in it, it is easy to cover that 4' wide bed with new plastic. If I didn't do this, I couldn't have a garden. We had a bad infestation of johnsongrass and it comes back year after year. There is no way to get rid of all of the stolons.