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).
Tim Miller, Washington State University. Mt. Vernon, WA.
Tim Miller’s Tips
We have tried using this technology, using a scale seedbed concept. The idea on this with our annual crops is we leave the soil after our final seedbed preparation, leave it alone and let the weed seeds germinate before we actually plant either seed of our crop or transplant into it. That gives plenty of time for the weed seeds to germinate that are up close to the surface. These are up then at the cotyledon stage of growth and we can use the flamer to remove those weeds either after we’ve seeded or just prior to transplanting.
Optimal Weed Size
Optimal time to really hit these weeds with this type of technology is at that cotyledon stage of growth; before we see true leaves start to show up. This small seedling is called smartweed. We have two cotyledons, it’s also a broad leaf plant, so the growing point is located up here at the top. This would be a prime candidate, right now, to control with flame technology.
If you look on the side, you can see that we have a pretty extensive root system, even on a plant this small. We’re down probably two inches to where the bottom-most roots are located in this soil. If you look next door to it, this is a common groundsel, another winter annual, it looks like 5 or 6 leaves, and its also starting to spread out, you can kind of see that here, amongst this soil, and a lot of these roots are well down deep. You can also that see we’ve got a pretty good mass on that stem, which is another indication that this plant would probably be able to survive the flame operation.
It’s very difficult to get control of grasses using the flame technology. The problem is that the soil is a very good insulator, and we just don’t get the heat that we need immediately around that crown to really cause those cells to desiccate. We can kill the top part of the plant, but we don’t really kill the bottom part.
We’ve used the flamer pretty effectively in blueberry production for instance. We’re able to get right underneath the crop itself, which is pretty effective. It does a pretty good job of actually removing the top growth of some pretty tough perennials like Canada thistle, horsetail, curly dock, things like this that are growing out in the field. We’ve found that this has worked pretty well for us. Obviously with a perennial crop like that, we are going to get re-growth, and we always do get re-growth, but we just plan on using the technology many times during the course of the growing season and we end up getting a pretty good level of control, or at least suppression of that perennial weed out there.
Now we do have to be a little bit careful, particularly in blueberry culture that uses sawdust and wood shavings out there in the row, to do this at a time when we’re not going to be setting the field on fire. I kind of joke about it but, we’re very careful to make sure that we have nice wet conditions in the sawdust. So springtime and after fall rains have started are when we really like to use the technology.