Weed Control That Actually Works
Most weeding effort is spent on weeds that should never have appeared.
Weeding is the job everyone resents, and almost all of the effort goes into fighting weeds that a different approach would have stopped appearing. The aim is not a weed-free garden, which nobody has. It is a garden where weeding takes minutes rather than afternoons.
Know which sort you are fighting
The two kinds need completely different treatment and treating them the same is why weeding feels endless.
- Annuals such as chickweed, fat hen and bittercress live one season and rely entirely on seed. Stop them seeding and you win, because the plant itself is trivial to kill.
- Perennials such as couch, kikuyu, bindweed, dock and oxalis come back from root, rhizome or bulb. Chopping the top off feeds them, and rotary hoeing them multiplies them, because every fragment grows.
The rules that do most of the work
- Never let one set seed. One season's seeding is seven years' weeding, and it is not much of an exaggeration. Five minutes pulling flowering weeds saves hours next year.
- Do not leave soil bare. Bare ground grows weeds, that is what it is for. Mulch it, crop it or cover it.
- Disturb the soil as little as you can. Every dig brings a new layer of dormant seed to the surface and starts it. This is the strongest argument for no-dig there is.
- Get them small. A weed at the seedling stage takes a second with a hoe. The same weed a fortnight later takes a fork.
- Weed after rain for perennials, when the whole root will come, and in dry weather for annuals, when the hoed seedlings die where they lie.
The methods worth using
- A sharp hoe, used shallow. The single most efficient tool for annual weeds. Skim just under the surface and cut them off, do not dig. Keep it sharp, and a dull hoe is why people think hoeing does not work.
- Hand pulling for perennials, ideally with a fork under the root. Get the whole thing, because a fragment of dock or bindweed is a new plant.
- Mulch, thickly. Five to ten centimetres of straw, leaves, compost or bark stops most annual weeds germinating. It will not stop established perennials pushing through.
- Cardboard under mulch for reclaiming a bad patch. Overlap it well, wet it, and cover with mulch. Left for a season it kills most things underneath, including a lot of perennials.
- Boiling water on weeds in paving cracks. Free, instant and nothing left behind.
- Close spacing. A crop that shades its own ground weeds itself.
What not to bother with
- Vinegar and salt sprays. They burn the top growth of annuals and do nothing to a perennial root, and salt in particular damages soil for a long time afterwards. Not worth it in a growing bed.
- Landscape fabric in a vegetable garden. Weeds root into it from above, it fragments into the soil, and lifting it years later is a miserable job.
- Rotary hoeing a perennial weed. You are propagating it, not removing it.
Not every weed is a problem
Some earn their place. Chickweed and purslane are edible and easy to pull. Dandelion roots break up compaction and the flowers are early bee food. A patch of nettle in a corner is a free liquid feed and a butterfly nursery.
The distinction worth making is between a weed that is competing with a crop, which should go, and a weed occupying ground you were not using anyway, which can often stay until you need the space.
See also: Mulching, which prevents more weeds than any amount of pulling, and Nettles, a weed worth keeping.