beating the weeds... mostly
Thursday 29th August 2013
Planting is finished for the year and, with most crops growing well, we’re busy catching up on weeding. My first summer of veg growing was spent bent at the waist, pulling up fat hen and cleavers; I didn’t like it much and we’ve spent the last 26 years developing ways to control weeds without hand work. We still get it wrong occasionally, as with our parsnips this year (saved with lots of hand weeding), but Riverford’s lessons on herbicide-free weed control go like this:
• Don’t let weeds go to seed in previous crops. The saying is, ‘one year’s seeding makes seven years weeding’.
• Preparing a ‘stale seed-bed’ is a highly effective technique. Most weeds emerge from the top 4-5cm of soil. Where time allows we prepare a fine, firm, moist seed bed well ahead of the scheduled planting date; as the weeds germinate we run blades under the surface, killing the young weeds and encouraging more to germinate. Repeating this up to four times reduces subsequent weeding by up to 90%.
• Sometimes we sow our seeds a week after the last cultivation, deliberately giving the weeds a headstart. Just before the crop emerges we run a flame weeder over it (essentially a giant gas grill) which kills the weeds, allowing the crop to emerge into the now weed-free seed bed.
• Next it is a race between the crops and weeds. We have a range of tractor-mounted hoes that control most weeds between the rows, and some within.
• With low density crops (eg. squash) we sometimes raise plants rather than sowing seeds, giving them a 3-6 week headstart on the weeds.
Pulling out weeds on hands and knees feels all wrong in the 21st century. It has even, on very bleak days when we are losing the battle, led me to question farming organically. In truth if we are following the principles above it is seldom that bad; weed control typically adds just 5% to cropping costs on a well-run organic farm. With time I have no doubt we will get it lower still.