1 - Grass can be weeds in garden.

Yard and Garden May 16, 2009

Q.

I have a family-sized vegetable garden overrun with weeds. These are mostly grass, either bermudagrass or crabgrass. My children and I have been pulling weeds almost every evening, but in just a couple of days the weeds have returned. I have been to garden centers and other places and they have not given me any useful information.

- Aric C.

Las Cruces

A.

Weeds are one of the challenges we face as gardeners. Grass weeds can be very difficult to manage. Of course, the weeds are effective competitors for water and nutrients that you have intended to nourish your vegetables, so weed control is very important.

There are several methods of managing weeds. It is important that you identify the weeds so that you can choose the most effective method for managing your specific problem. Your local NMSU Cooperative Extension Service agent can help you with this.

You said you have either bermudagrass or crabgrass. Knowing which grass is your nemesis is very important. Since it returns quickly, I suspect it is bermudagrass, but I still recommend you take a sample to your Extension Service agent. Crabgrass is a summer annual. It can be pulled and must return from seed. Preventing seed formation will reduce (not eliminate) problems next year. Bermudagrass is a perennial grass growing from underground structures. These permit it to return quickly once you pull it. That is why I suspect bermudagrass is your problem.

Pulling and hoeing are effective means of limiting the growth of bermudagrass, but this does not eliminate it immediately. If you will persistently pull it and dispose of it, so that it cannot begin growing again, over time you can weaken it so that it at least becomes less of a problem. Your goal will be to prevent the grass from growing enough to send food to the roots and underground stems. In time, the food reserves needed to support regrowth will be diminished and the grass will return less quickly.

Mulch can also help. Bermudagrass will grow through most organic mulch materials (grass clippings, straw, wood chips, etc.), but the mulch can make it much easier to pull the weeds when they return. If your lawn is bermudagrass, do not use your lawn clippings as mulch.

Finally, there are chemicals that may be used to manage weeds. Your Extension Service agent can give you advice regarding which are available and appropriate in your situation (after identifying the weeds). If you are interested in chemical control, these products may help, but they will also require persistence as well as knowledge regarding the proper and safe method to use them. Most gardeners will use herbicides very sparingly and carefully around the garden or not at all. There are some grass specific herbicides that kill only grass weeds, but remember corn and some other crops are grasses.

Marisa Y. Thompson, PhD, is the Extension Horticulture Specialist, in the Department of Extension Plant Sciences at the New Mexico State University Los Lunas Agricultural Science Center, email: desertblooms@nmsu.edu, office: 505-865-7340, ext. 113.

Links:

For more gardening information, visit the NMSU Extension Horticulture page at Desert Blooms.

Send gardening questions to Southwest Yard and Garden - Attn: Dr. Marisa Thompson at desertblooms@nmsu.edu, or at the Desert Blooms Facebook page.

Please copy your County Extension Agent and indicate your county of residence when you submit your question!