The Kerr Center for Sustainable Agriculture: Managing Weeds Organically

By Tom Zink, Horticulturalist

One of the struggles gardeners face each year is weed management. If left unchecked, weed pressure can ruin a garden fast. Weeds compete for plant nutrients and water, provide shelter for harmful insects, and can even harbor diseases that may spread to planted veggies.

This article discusses organic management methods and tools that permit weed control without resorting to harsh chemicals, thus preserving the fruits of your labor.

One of the main tools we use for large-area weed control is silage tarps. Preferably 8 mil in weight, these tarps smother out weeds in a large area. Depending on the temperature and moisture levels, these tarps can smother and kill weeds in as little as two weeks, but on average take a month or more. They can be used in conjunction with cover crop plantings as well.

Firstly, smothering out the plot with tarps, then planting cover crops, chopping the cover crop down at maturity, and smothering the cover crop mulch will not only smother out weeds, but also add fertility and organic matter to future plots. This is an excellent technique for breaking new ground.

Tarps can also be used in a plot and bed system by simply uncovering each bed individually as needed for planting and keeping the tarp over the rest.

Woven plastic mesh ground cover is used often on the Kerr Center Horticulture Farm. Vegetables are planted into it directly, and it’s also used as a preventative cover for plot borders or walkways. It is available in assorted sizes depending on function. Held in place by garden staples, this is the easiest way to control weeds in and around the garden over the long term.

On the 30″ bed system, it is typical to use the 36” wide fabrics for transplanted crops. The wider fabric eliminates the need to hand-weed or spray chemicals throughout the growing period, while also helping to regulate soil moisture. Fabric is cut to the needed length, and holes are burned into it at the desired spacing based on the crop. Unlike plastic mulch, woven fabric allows for airflow, inhibits moisture exchange, and is reusable over many seasons.

Managing weeds isn’t fun, but if the correct tools are on hand, the chore is a breeze!  On the farm, an assortment of hoes is used based on the job at hand. It is easy if you weed frequently while the weeds are very small.  Allowing them to develop extensive root systems makes control difficult.

To clear walkways between beds, use the triangular scuffle hoe.  This hoe is equipped with three blades and can be used in a pushing or pulling manner. The goal is to get the tool head slightly below the soil level and pull up the roots of the weeds.  A hoe like this prevents you from having to squat down as it is used standing and works well even in hard packed soil.

For working weeds in the beds, a few different hoes may be used, as it is all based on personal preference and workable space.  The stirrup hoe tends to be one of the favorites.  Shaped like a horse stirrup with an inside sharp side, it is used in a pulling motion cutting through the soil and unwanted weed roots, pulling them up.

A collinear hoe is used in the same way as the stirrup hoe and comes in multiple sizes.  This hoe is recommended in tighter spaces, and in between plants to prevent damage.

Wheel hoes are another option, used to clear walkways or beds being prepped for planting.  The wheel hoe is essentially a bigger version of a stirrup hoe that’s on a push wheel and can do a larger space faster, preferring lighter soil with less compaction to work properly.

The densest weed growth usually occurs around the edges of plots or greenhouses. In these areas, organic spray proves to be beneficial.  Organic herbicides tend to be broad spectrum contact herbicides, meaning they will kill anything on contact. For this reason, it’s important to spray carefully and in the right conditions to prevent wind drift and carry.

Torched™, made by Southland Organics, is the preferred choice on the farm.  Available online, it is an all-natural, non-selective herbicide made from a proprietary blend of essential oils and soaps that eliminates weeds without using harsh, synthetic chemicals.  Although Torched™ does not contain potentially harmful chemicals, it is recommended to use protection such as gloves and goggles during application.

Burning weeds with a propane powered flame weeder is yet another effective method for suppression.  Available at most farm and ranch stores, this tool works by incinerating small plants before they can develop into problematic weeds.  Both herbicide spraying and flame weeding require careful use but are quite effective at controlling larger areas.

There is no one-size-fits-all solution to weed management.  Combining methods and tools to control the invasive weeds in the garden is the best way to get ahead of them.  Place fabrics around plot edges and as a plantable mulch.  Use hoes to control weeds on the bed edges and walkways. Spray and burn weeds on the outer perimeter to prevent encroachment.

With proper management each year, weed pressure will become lessened, making life in the garden much easier and enjoyable!

 

The Kerr Center has been a consistent innovator and leader, the first to bring new ideas and sustainable practices to the Sooner State.

On its 4,000 acre ranch near Poteau, the center has tried out these new ideas, demonstrating the practical dimensions of sustainable agriculture– with horticulture, livestock and natural resource conservation projects.

Education has been its primary mission, through events, publications and now the web.

Since 1965, the Kerr Center has been an effective advocate for Oklahoma farmers and ranchers, for rural communities, and for a healthy, sustainable food system, from gate to plate.