They're the bane of every kitchen gardener's life and they seem to appear the moment your back is turned. I'm talking about weeds of course! I recently tried to work out exactly how much time I spend weeding – either on my haunches plucking weeds one by one from between my veg, or slicing (or, rather, gliding!) back and forth with the hoe. Perhaps unsurprisingly the answer I came to was 'a lot' of time.
By the middle of summer you will either have managed to keep your plot pristine or the weeds may well be gaining the upper hand. Hopefully you are in the former camp, but even if the weeds are growing thick and fast it's never too late to whip your plot back under control. The secret – and this can't be emphasized enough – is to never let those weeds get out of hand again. There's absolute truth in the old adage 'seven year's seeding means seven year's weeding'.
Weeds can be divided into two known enemies: the annual weeds that set seed in a blink of the eye, often in as little as three or four weeks, and perennial weeds, which will spread primarily by stealth means, creeping along using rhizomes, roots and by layering. Both types of weed need to be tackled in slightly different ways.
The trick with annual weeds such as chickweed, bittercress, fat hen and groundsel (to name just a few) is to snuff them out while they're still young. Just-germinated seedlings can be tackled with ease by dislodging them with a sharp hoe. Compare this with fully grown weeds and it's easy to appreciate why tackling them at this stage is preferable! Get into the habit of checking over your vegetable garden at least every other day. It can feel like weeds are resolute in their determination to surface but every weed removed is one less seed in the soil's weed seed bank. Eventually your ground will become relatively clean of weed seeds and the job will become much easier, though of course you'll always need to be on hand to deal with weeds coming in off wind-blown seeds.
Play detective – look under the leaves of crops and pull out any lurking weeds. It may be a bit of a faff climbing in among the undergrowth but it will keep weeds from flowering and pay dividends in the future. Always think at least one crop ahead. The current crop may take the weeds in its stride with no ill effects on what you harvest, but what about the next crop? If you leave those apparently harmless weeds to their own devices they will only set seed and render the vegetables that follow a challenge.
Mulching between plants with well-rotted (and clean!) organic matter won't just suppress annual weeds by suffocating them before they've got going, it will gradually improve the structure of your soil, making it fluffier and easier to extract those weeds that do appear. In time you will move towards a fertile soil that's low in weed seeds and that favors your crops, not the likes of sow thistles or willowherb!
Rambunctious perennials such as bindweed, couch grass (twitch/quick grass), nettles, dandelions and ground elder get something of a bad press. But while at first glance they might appear to be insurmountable, you can and will eventually win the war of weeds over these guys!
Where individual perennial weeds or manageable clumps exist there's no better remedy than digging them out with a trusty fork. While some perennials can re-sprout from the tiniest fragment of roots and require meticulous picking over to remove every last morsel (couch grass, bindweed, horsetail), others are more forgiving and will die so long as their main root is removed or severed deep down (nettles, docks, brambles). Roots of pernicious creeping weeds can be drowned in a bucket of water before the resulting slop is added to the compost heap.
I'm often asked by disheartened gardeners what the solution is to a thick mat of perennial weeds. The solution here is time – and plenty of black polythene. Hack back the worst of the top growth (this can be put onto the compost heap), add a layer of compost or well-rotted manure over the remaining stubble then cover the whole lot with thick black polythene. The polythene has to be black to exclude the light. It will weaken the weeds beneath over time, causing them to fail and rot down into the soil along with all that organic matter. Keep the polythene in place for at least a year then dig over the now weed-free soil. The ground needn't be wasted space over those 12 months – lay grow sacks and containers over the surface and plant into these instead.
If you want to convert a weedy patch that isn't full of really pernicious weeds you may get away with covering the soil with cardboard before adding a 10-15cm (4-6in) layer of compost on top. This can then be used to grow your crops while the weeds beneath are suffocated by the cardboard. The cardboard should rot down within a season, remaining intact just long enough to see off the grass and weeds beneath.
If there's one take-home message from all of this, it's that persistence does pay – I promise! Keep on top of the weeds and don't let them bully you into submission. Catch them while they are young, remove all roots of persistent perennial weeds and never, ever let annual weeds set seed.
By Benedict Vanheems.