quack grass removal

Asked November 2, 2016, 4:02 PM EDT

Hello, My garden in my community garden got overrun with quack grass this year because circumstances caused me to neglect it. I'm told I need to use a hoe or shovel to dig is all out by hand. We are an organic garden. Is there a gentle type of rotary hoe that would help do the work? A mechanized on would be great because the plot is 20'x 20'. I could sift out all the roots after that, which would be easier than all the digging and sifting. Would that work? After that, how do I keep the other gardeners quack grass from invading my garden . T Thank you! Becky

Ramsey County Minnesota

3 Responses

The quackgrass will be tough to deal with because of the extensive underground rhizomes. To eliminate the quackgrass you need to kill the rhizomes - unlike annual weeds, simply pulling them will not take care of the weed unless you do it repeatedly throughout the season. There used to be tools known as quack diggers designed to drag the rhizomes to the surface where they would desiccate. They would have to be run 6-8" deep so you would need a small tractor to pull them through the garden. Rototillers cut the rhizomes into small pieces, resulting in a greater density of shoots. If you could repeatedly do this every time the new shoots reach 4-5" you can drain the energy reserves. Unfortunately with your short growing season you would lose most of the season. Mulches can be used, but they need to be at least 6" deep or the quack grass will be able to push through. Probably not an option to take the area out of production for one year to eliminate the rhizomes. If there are adjacent plots that people don't control the quack grass it will be a never-ending battle. The big problem will be the creeping rhizomes moving into your plot rather than seed. You could eatablish a 1 or 2 ft buffer around your patch that you tilled every 2-3 weeks to kill any rhizomes moving into your area. Sorry I don't have a simple solution.

Thanks Bob. Is there an edging product that I could use to separate my garden from the other gardens to keep quack grass from spreading back into my garden? How deep would it have to be? Could I use a green manure cover crop to smother the quack grass? I know I would have to remove the quack grass first, but I know much of it would likely grow back again, so I'd like to smother it. I am willing to take my garden out of production for a year. Becky

Becky, Thought I responded earlier to your second question, but maybe I hit the wrong button. A barrier would have to be at least 6" deep. Treated lumber would work, but not sure if that's allowed in organics. A simpler option would be to just dig a trench and place 2, maybe 3 layers of landscape fabric to serve as a barrier. Never heard of it being used in this way, but don't know why it wouldn't work. Over time I assume some rhizomes or roots of some other weed might penetrated, but seems like it should serve for several years.
The green manure cover crop is a great idea. Quackgrass is a cool-season species so you need to select a species that will be highly competitive in the fall and early spring. Cereal rye is probably the standard cover crop, but there are advantages to using a mix of species. If you went with rye you would want to seed something after the rye matured (I assume that would be late May). For this spring you could seed a summer cover crop, buckwheat is a standard, and then rye could be planted in late August.