Grow veg

Tips you need to combat the scourge of weeds

‘A weed is a wild plant growing where it is not wanted and in competition with cultivated plants.’

Some people say that a weed is just a plant growing where you don’t want it and there is truth in that, but weeds become a problem because they compete with, and often out-compete, the plants we want to grow.

Weeds become weeds because they’re fast-growing, prolific self-propagators. They’re not remotely fussy and are superbly adapted to exploiting any piece of soil they can get their roots into. In many ways we should admire them, but we also need to keep them at bay or our crops will struggle.

This is a year-round problem, so here are some tips for each season.

Winter

Cover it up: Even in the middle of winter weeds and grass can grow whenever the weather is mild, especially if there’s a lot of empty soil for them to spread into.  Black plastic and thick woven fabric like the one in the picture don’t look pretty, but if you use them to cover empty beds, they stop weeds and grass growing very effectively.

Job done? Yes, and no. These plastic coverings are light in weight and effective at suppressing weeds, but the drawback is that over several months of bad weather, especially heavy rain, they can leave you with flat, compacted and soggy soil which is difficult to plant into. I always cover my soil with a woven fabric in winter and for me it’s certainly the lesser of two evils even though my soil is heavy clay. If you don’t want to weed during the winter months, I suggest you give it a try in a small area and see if it works for you.

Dig or no-dig: In late winter we start to think about soil preparation for the season ahead. Double-digging used to be the norm for veg beds and was a technique I was taught on the first horticulture course I took, but thinking has changed since then. Digging and using mechanical tillers to loosen the soil can clear it in the short term and make it a lot easier to plant and sow seeds into, but you throw up weed seeds in the process and disrupt the natural structure of the soil. If you can avoid heavy cultivation, you can save yourself not only that work, but potentially a lot of weeding in the following weeks.

Winter tip: Cover the soil with a layer of black plastic or woven plastic fabric and avoid a lot of heavy cultivation if possible

Spring

Spring is when the fastest weed growth happens. The soil starts to warm up and there’s that perfect mix of sunshine and showers which means that plants have the ideal conditions to grow. Including weeds of course, so this is the key time to keep on top of them.

Mulching: As in winter, covering the bare soil helps, but what with?

Planting through black landscape fabric or the woven plastic fabric used over winter keeps weeds at bay and keeps moisture in the soil through summer. But you can get colonies of slugs and snails living under it, which leaves you with different problems.

Home-made compost works, if it doesn’t have weeds seeds in it, and it helps soil fertility and structure. Green waste manure from your local council should be weed-free and is reasonably priced, if you can get it. Well-rotted horse manure is excellent, as long as the horses haven’t been eating grass treated with hormonal weed killers.

Strulch, a mineralised straw mulch you can buy by the bag, is very effective at keeping weeds down and puts off slugs and snails as well, though it could be a bit expensive.

Bark chips work brilliantly in flower borders, but not so well in the veg bed where they can get worked into the soil too quickly and use up vital nutrients while the rot down. Cover paths with it, but not beds.

Weeding: All those mulches will help, but some weeds will still grow and start flowering and producing seeds very early in the season. Regular hoeing and hand weeding are going to be needed, unless the soil is saturated and sticky because it’s almost impossible to do it properly In those conditions. Weeding on a dry sunny day is best because its physically easier and exposed roots will dry out quickly.

Spring tip: Weed regularly to stop them reaching flowering/seeding stage and cover the soil either by planting through fabric or by using an organic mulch.

Summer

Critical weeding windows: A lot of research has been done into weed competition in agriculture, and it’s been shown that when plants are young and trying to get established, they can quickly get overwhelmed and outcompeted by weeds. Once they’re bigger, though, they can cope with the competition better.

Potatoes, which should be fully grown by early summer, are brilliant at suppressing weeds with their foliage and even carrots have been shown to compete well with weeds if they’ve had time to get established and grow to a reasonable size first. Some veg, such as onions which have sparse leaves and can suffer if a lot of weeds grow round them, aren’t so easy, but generally if you go on holiday and come back to find the weeds have taken full advantage of your absence, it’s not the end of the world for most crops and you just need to remove the worst of them as soon as you can.

Summer tip: Weed growth often slows and plants should be established enough to cope with some competition. You should keep weeding, but it can be done less frequently.

Autumn

Depending on what you’ve been growing, a lot of your crops might be coming to an end now. As you empty the beds and add all that material to the compost heap, you’ll undoubtedly find sneaky weeds that have appeared recently, or bigger ones that have been hiding among your plants. Whether you plan to cover the beds now or leave the soil bare, it’s a good idea to clear as many weeds as you can rather than leave them to grow and add to the weed-seed bank in your soil.

Autumn tip: Clear weeds as you clear the beds and if you’re going to cover them up for winter, do it as soon as possible. Fix the covering material down well so it doesn’t blow off.

What to do with your weeds: Annual weeds that haven’t started to flower or set seed can go into the compost heap. Perennial weeds, especially things like bindweed and couch grass which can grow from tiny bits of root, are better being burnt, assuming you’re allowed to have bonfires where you are, unless you know how to create a properly hot compost heap.

More on that later.

Categories: Grow veg

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