Weed Management on a Budget

Posted: November 20, 2011

If you are looking to scale up your organic farm next year, you may be dreaming about using a tractor mounted cultivator. A wet year like this one, where the weeds got out of control, is a good reminder of how important it is to have a weed management plan, and the tools to execute it.
Cultivating sweeps belly mounted on kubota tractor.

Cultivating sweeps belly mounted on kubota tractor.

If don’t have a big budget to work with, you may start with a simple tool bar system. You don’t need a big tractor. Your twenty-five or thirty horse power Kubota or old Farmall is plenty. The simplest set up is a tool bar with a set of sweeps, shovels or knives. These are tools that attach to the end of a shank (rigid straight or curved piece of steel). The shank is attached to the toolbar with a clamp. The shanks can be clamped to different places on the tool bar. This lets you adjust for different row spacing with the same piece of equipment. Sweeps are standard. Sweeps are wing or arrow-shaped. The point faces forward and the wings cut right under the weeds, digging them up and throwing some soil into the crop row. The faster you drive, the more soil you throw into the row burying hard to get in-row weeds. Big sweeps, or duckfeet, are often used to cultivate the wheel tracks. A standard set-up is double toolbar with six clamps, shanks and sweeps. To cultivate three rows four sweeps would be down, one on each side of each row. To cultivate one row the center sweep would be lifted (turned upside down in the clamp) and two additional sweeps lowered. This set-up allows you to cultivate one, two or three rows without moving the clamps.

The type of tool, as well as the arrangement of shanks and toolbars determines the amount and direction of soil movement and the area that gets cultivated. Narrow shovels with sharp points uproot aggressive weeds like quackgrass. Half-sweeps work up close to the row or along the edge of plastic mulch. Side knives cut parallel to the soil surface, sideways under the crop canopy, allowing close cultivation. Rusty tools may not cultivate well and rusty clamps make adjustments difficult.

Three things I like about toolbar systems are 1) you can often find a used tool bar for cheap, 2) they are versatile and you can add more precise or sophisticated tools as they are warranted, and 3) they don’t require a large, specialized tractor or PTO. The entire set-up can be put together for $500. Wasco Hardfacing Co. and Agri Supply are a couple of sources for a wide variety of sweeps, knives, shovels, shanks and clamps. Take a look at auction, used equipment dealers and your neighbors for tool bars, clamps and even shanks and shoes.

Going to tractor cultivation is not without challenges. Your plant spacing needs to be straight and even. Use row markers attached to your tool bar if you plan to seed with push seeders or transplant by hand. Believe me cultivating crooked rows will take out your crop and then you are back to hoeing. Also your beds or fields need to be relatively flat. Sweeps and knives are set to just barely cut under the soil. On an uneven bed they will bounce out or dig in.

Whether with hoes or tractors, good weed management is all about having a system. Timing, cover crops, keeping weeds from going to see as well as good tools are all critical. Take some time this winter to sit down and farm on paper. Think about what worked this season, what did not and how to make the pieces of your new system fit together. There are many great books including Vernon Grubinger’s Sustainable Vegetable Production. For more information on setting up an organic weed management plan, cased studies and examples go to Creating a Weed Management Plan for your Organic Farm.