During summer as many vegetable crops mature, their growth is little affected by growing weeds. Ripening of onions may even be helped by weeds that take nutrients and help onion bulbs to stop growing.
But in the longer scheme of things, weeds that are allowed to grow freely cause two major problems. Firstly they risk setting seed. Each plot has its own specialities, here I find that groundsel is the quickest to flower and then distribute hundreds of new seeds. Just a handful of plants doing that will make extra work for years after. Secondly the roots of perennials such as dandelions, bindweed, couch grass and buttercup will grow stronger if their roots are fed by leaves that are given free rein.
So I really recommend that you keep on top of weeds at all times. At the moment I go hunting for them amongst squash, asparagus, climbing beans, beetroot and parsnips, which are all in full growth themselves and look clean. It doesn’t take long to have a look and pull out the odd weed… also I am pulling out any odd grasses that pop up in pathways, thanks to the wet weather.
I have recently removed a piece of carpet from one of my beds. The patch has been covered for about twelve months maybe more and is clear of weeds except for bindweed roots running along the surface. I had to cover some of my plot because it really was too much to manage alone in the beginning.
I intend to cover with compost/manure and experiment with the “no-dig” method but will I need to removed the bindweed roots first?
Yes they do need removing because they are still alive. However, twelve months of no light has weakened them and brought them closer to the surface so removal is easier; I use a trowel to loosen the soil a bit and follow any downward roots to be as thorough as possible, before spreading compost or manure.