Flame Weeding

Weed management is one of the biggest challenges in organic farming. At Gathering Together Farm, we rely on an integrated approach using seedbed preparation strategies, cultivation, and hand weeding. A method of weed control that is very effective for our direct-seeded crops is preparation of stale seedbeds. Every time the soil is disturbed, a new flush of weeds germinates from the soil seed bank. The stale seedbed method relies on a tillage pass, then waiting for the weeds to germinate, killing the emerging weeds with flame, and then planting our crop.

We are currently in full-steam-ahead planting mode, getting our five acres of high-tunnel greenhouses planted with mustards, spinach, arugula, mâche, carrots, beets, turnips, radishes, bok choy, and peas. Pictured below is a greenhouse where our production manager Joelene has already raked the soil to create a fine seedbed for planting arugula and mâche. After a couple weeks of waiting, the weeds have emerged at cotyledon stage and are rapidly killed by a quick pass with a propane flame.

 

Our agronomist, John Yeo, has put together new backpack flame-weeder setups with a burner for each hand. In the past, whoever was flame weeding would carry the propane tank in one hand and hold the burner in the other. With this new contraption, the propane tank fits on John’s back, and he can burn twice as efficiently with a burner in each hand, and more ergonomically than carrying the tanks.

Flame weeding works well on dicotyledon weeds, or dicots for short. A dicot is a flowering plant that bears two cotyledons which emerge from the seed itself, however doesn’t work so well on grasses, as the growing point is below the soil level where it stays protected from the flame. Often established weeds won’t be as affected by flame weeding, which is why timing is essential for this operation. If we catch the weeds at the cotyledon stage, they can be eradicated in this efficient manner. Reducing our on-farm weed pressure has been one of John Yeo’s primary goals since he started with the farm in early 2015. He’s excited to apply concepts of biology and timing to the weed management program for another season of growing exceptional certified organic vegetables.

Here are a couple of videos that demonstrate our flame weeding practices: