University of Vermont

The Battle of the Weeds

Mulch around flowers
Photo courtesy USDA

By Bea Cole

Extension Master Gardener, University of Vermont

You may have considered a garden but dismissed the idea because you didn't have the time to weed. Or maybe you've had a garden in the past but found weeding to be too much work. Mulching can address this problem.

Mulching your vegetable garden not only cuts down on weeding but also cuts down on water evaporation. It will encourage helpful soil organisms and reduce soil compaction. Mulch can heat up or cool down your soil temperature depending on the type that you use.

Many kinds of mulch add organic matter to the soil and help with erosion. Mulch also prevents disease by keeping soil fungus from splashing up onto the plants. 

There are many different mulch materials that can be used in the vegetable garden to greatly reduce the amount of time spent weeding. Here is a list of the some of the popular choices:

Straw or hay. Straw is the best choice of the two but can be expensive to buy. Hay should be seasoned so that you don't end up with weed seeds from the hay.

Grass clippings are something that almost everyone has. Use thin layers or let the clippings dry slightly before using. They will shrink as they dry so you may have to add a second layer. Grass clippings add nitrogen to the soil so use them early in the season. In late summer mature plants don't need more nitrogen.

Leaves add nutrients to the soil as they break down. Chopping them up with a lawn mower makes them less likely to blow around. Leaves should be aged for nine months before being used. Put them in a pile and leave them for a season. Be careful when importing leaves from other locations as they could contain invasive snake worms or other invasive weeds or insects that you don't want in your garden.

Black plastic in sheets can be fitted around plants but make sure that it doesn't limit the water supply to your plants. This product will heat up the soil so anything in the same family as tomatoes will like it, such as peppers and eggplants. It will have to be removed in the fall as it is not biodegradable. 

Wood or bark chips take several years to break down in the soil so these are suitable for permanent rows between raised beds. Fine sawdust is really not an ideal garden mulch.  It tends to rob nitrogen from the soil as it breaks down, which creates a carbon to nitrogen imbalance.

A variety of mulch options can be used in the garden depending on the needs of different plants.  So try using some mulch this season especially between rows. You will spend less time weeding and more time enjoying your garden.

For answers to gardening questions, call the University of Vermont Extension Master Gardener Helpline toll-free at (800) 639-2230 or (802) 656-5421. Or sign up for the Master Gardener course this fall www.uvm.edu/extension/mastergardener.