I've toyed around with using various crops to help shade out "weeds" and improve the soil for future garden plots. Tropical grasses are my number one weed, and they are very hard to eliminate without using a herbacide or else covering the ground in black plastic (or something else durable and solid) for many months. I decline to broadcast spray herbacide and I'd like to come up with a solution that doesn't involve spending lots of money. Giant rolls of black, heavy grade, durable plastic sheeting aren't cheap. I'm cheap, rolls of plastic aren't!
Since I already have a decent amount of veggie producing beds, I'm not in a real hurry to get more ground into production. So time is on my side. This gives me time for tinkering around with ideas.
I have some sort of a taro that really likes to grow here. It produces giant leaves when fertilized with manure, thus creates dense shade beneath itself. So I've been using it to help get rid of weeds.
Above, I measured some of those leaves. Many were close to four foot long! Without lots of manure being used, the leaves are more usual 18"-24". But since I'm looking for complete shade, the manure helps make those jumbo leaves.
The shade beneath this taro keeps most weeds from thriving. The weeds tend to be spindly and small. About once a month I'll throw some grass clippings between the taro plants to act as a smothering mulch. It works on just about everything but certain grasses. But the grass also gets spindly with weak roots. So it becomes fairly easy to pull out. After several months of grass clipping mulch and hand pulling what grass happens to survive, the area becomes almost weed free. Not quite, but much better than before.
This particular taro patch is just about ready for converting to a veggie garden. The beauty of this system for me is that I don't have to dive in and plant veggies right away. There's no rush. The taro will still grow for a number of months, giving me time to get my act together. Plus....with all the manure and mulch being used, the soil has had a chance to become fertile and a home to scads of worms.
This particular taro is quite "itchy". So I don't bother trying to use it for people food. But I will cook it on my outdoor wood burning cook stove for feeding to the chickens and pigs. The corms need 2-3 hours of cooking to make the pigs happy, but the chickens will eat it with much less cooking. The leaves and stems need at least an hour for happy pig food. Since I have a virtually unlimited supply of cooking wood, it doesn't cost me anything to cook it for so long. I wouldn't bother with it if I had to pay for fuel. I would just add it to the compost pile instead.