Weed 'Em and Reap Part 1: Tools for Non-Chemical Weed Management in Vegetable Cropping Systems [DVD]. A. Stone. 2006. Oregon State University Dept. of Horticulture. Corvallis, Oregon. Available at: http://www.weedemandreap.org (verified 17 Dec 2008).
Rob Heater, Stahlbush Island Farms. Corvallis, OR.
These are a couple flamers that we’ve built for row flaming. They’re a hooded flamer, just simple, steel hoods we’ve built with a thermal weed control propane head in each one. It boxes in the heat, and it lets you use a lot less gas, go faster, and we only flame the stuff that’s emerging, we don’t try flaming once the crop is up. It does a pretty effective job of killing the first flush of weeds that are really there to compete with your crop.
You only need to provide enough heat, just a flash heat. Just like on my skin, the cells on the epidermis on the leaf, you’re trying to basically boil the water in those cells to where it ruptures the cell walls. When plants are very tiny and quite fragile yet, you do that kind of surface damage, the plant just hemorrhages and dies just within minutes behind you, and it doesn’t take that much heat or gas to do that.
We wanted to not have a big heavy steel propane tank so we went with aluminum. They’re 10-gallon, upright, propane tanks all manifolded together. Typically when we’re flaming, we can go about 6 miles of flaming between fill-ups. We usually have the guys in the 4-wheelers just set the trip odometer, so they kind of know when to expect they’re going to be running out of gas. They can usually go around 6-7 miles, which is quite a few acres.
We’ve got an electric winch on the back that’s wired to the four-wheeler. We have a winch control on the handlebar. We can raise and lower the hoods. We have an electric solenoid valve that switches it from pilot to full burn, so when they get to the end of the row, they flip it to pilot, and the gas shuts way down, its just a very small pilot stream that keeps the flames lit. We typically run either three, four, or five miles an hour depending on how many weeds are there, how cloddy the ground is, and if there’s any grass types or broad-leafs. Grasses are much harder to kill, so we typically go slower. We usually run the gas pressure anywhere from 25-35 psi. On average, this costs about $5/acre to flame and that is including the fuel and the person driving the four-wheeler, their wages, so it’s very, very cheap.