Last year I decided not to mulch a good chunk of our garden, in the interest of seeing how hard it was to maintain if mulch materials wereever scarce. I love permanent mulch - I love the way the soil improves under it, I love the way that the soil stays moist when it is dry and also handles heavy rainfall much better, and I love sitting on the warm mulch while I pick tomatoes or cucumbers. But I don't wantto be too dependent upon any particular gardening method, so I left a patch in front of the house (on the theory that sheer embarassment might encourage me to weed) unmulched and went about my business.
This was partly fueled by a discussion I had a few years ago with afriend of mine who is an herbalist and gardener at Sturbridge Village(an 1830s living history museum), who pointed out that most garden descriptions of the time are very unconcerned with weeding, and many permitted large quantities of weeds to grow up as mulch underneath plantings, just pulling them as they began to shade other plants. I've done that a few times by accident, but this, (besides proving that embarassment will not drive me to weeding if there is anything more fun to do ;-)), was my first formal experiment. I have to say, I think the weeds have done me more good than bad. Now obviously, ymmv, and those of you with moisture shortages or very tight spaces probably won't have this luxury, but my observation so far has been that as long as the weeds aren't allowed to take over completely, or to shade out food plants, that the competition isn't a bad one, necessarily.
My weedy tomatoes have actually grown faster than the mulched ones, and set fruit earlier than mulched varieties ofthe same species. I've been managing the weeds, rather than completely getting rid of them. Some, we eat or use for medicinal purposes, and that takes care of that. I pull out the lambsquarters and wild salsify as I eat them, but don't worry too much about them when they are small. I'm lettingsome of the wild oats that aren't too much in the way mature, and will feed them to the chickens. I even transplanted a few over to a better spot ;-). The mulleins I left because I think they are pretty, and if there's ever a shortage, the leaves make terrific toilet paper. Some of the greens (extra plantain that we don't want, pigweeds, chickweed) go straight to the chickens and geese as harvested feed. Then, there are some weeds I'm actually delighted to see - I've never had them before, and I want them. I'm encouraging the wild yarrow to grow, since I find it better for medicinal purposes than the stuff I cultivate, and it is lovely - one of my favorite wildflowers. This is the first year I've had either purslane or stinging nettle anywhere on the property - I've always had to forage elswhere, and I'm more than a little pleased to see them. Both are fairly well-behaved (in that they don't really take over), and very good to eat (use gloves with the nettles, and cook them first). I'm also excited to seecteasel here - people in upstate NY used to grow fields of them for thewool processing industry, and I'm planning on harvesting mine for thesame reason. Plantain I like to let go to the green seed stage, and then harvest and dry the seed heads - they make marvellous free birdfood in the winter. Pigweeds and other wild amaranths are great for the same purpose. Bedstraw and Burdock are allowed to mature until just before they set seeds, and used for dyeing and eating respectively (ok, I don't always get to them before they set seed, which is a problem).
I also always allow some weeds to go to flower on the fringes of the garden. Along with the dill and cilantro I plant to attract pollinators, I notice that queen anne's lace and mullein are good insect attractants. Canada and Bull thistle get taken right out, as do a few others, like ground ivy, which are real pests. I reserve the right to kick out any weed that takes more than its fair share, or sticks me with prickers when I step on it. But for the most part, weeding is a desultory chore for me, done at a fairly low key. As long as the plants aren't too crowded or shaded, and the weeds are useful ones to me, leaving them be doesn't seem to do a lot of harm to *most* crops, and the weeds will generally get pulled for whatever purpose eventually.
There are exceptions -peppers here are easily shaded out by faster growing weeds, and carrots can't handle any weed pressure at all. But for every crop that needs hand weeding, there are those, like bush beans, zinnias,tomatoes and corn that on fertile soil, with adequate moisture, seem entirely untroubled by competition, and that will eventually shade out the weeds on their own. My math so far suggests that I actually take more useful plants off of my land when I plant a little further apart and allow some weed competetion than when I plant my own food plants more tightly together.
One of the biggest pests in my garden is the tomato. No matter how diligently I harvest, every year I spend more time pulling out fast growing tomato volunteers than I do burdock or thistles. They tend to shade everything out, because they grow so fast. I leave some, of course, but it does point out that even in my cold climate, I could probably rely for much of my tomato crop on volunteers, provided I didn't mind waiting until September to harvest (I do). I'll probably go back to mulching next year - after I transplant in my plantain and wild yarrows. But the other advantage of leaving the weeds, assuming you can afford the loss in moisture and fertility, is that pulled weeds make an excellent mulch. If I ever run out of straw and undercropping material, I probably will do just that and allow theweeds to grow up, pull them, and use them to smother the rest.
I think it worth praising the weeds, at least once in a while,before I squish them ;-).