Man with weed wacker in garden

Mustard is a great cover crop for the fall garden in preparation for later planting of garlic. Mustard has bio-fumigation properties which destroy plant diseases in the soil.

Naked ground is never a good thing for a vegetable garden. As the growing season winds down and spent plants are pulled up, there is more and more open space in our garden. Leaving bare ground at any time leads to decreased soil quality. For one, in a year such as this where rains have been so frequent and often heavy, soil erosion can occur simply by the splashing away of soil particles. Also, with saturated soils, the finer clay particles will come to the surface where they’ll form a barrier to water and oxygen infiltration; it looks like someone has plastered the soil surface with clay. Another consequence of bare ground and frequent rain is a decline in soil fertility due to the leaching of mineral nutrients. And lastly, open ground is an invitation for weed invasion. So, what is one to do?

The simplest solution is to plant a cover crop. This is not a crop that one will be planting to harvest for the kitchen table. Rather, the function of a cover crop is to prevent soil erosion, sustain nutrient levels, contribute organic matter, suppress weed growth, and in, some cases, suppress soil borne diseases and pests.

Common cover crops to plant at this time include buckwheat, clover, vetch, winter rye, and sorghum-sudangrass. One which I am now planting is mustard. It will only be in the ground until mid-October at which time I will till it in. Two weeks after that, garlic will planted in that location. The primary benefit of mustard is its ability to suppress soil borne diseases and nematodes, which have been a serious problem for growers of garlic. Though they are not thought of as a common cover crop, I’ll also be planting leftover bean and pea seeds soon. As legumes, these plants will contribute much nitrogen to our garden soils. These, along with my winter wheat, will not be tilled under until spring.

Preparing soil for cover crops is no different than for any crop. Simply, scatter some fertilizer, till the soil, and then scatter and lightly rake in seeds of the cover crop. A no-till method may also be used. In that situation, scatter seeds and fertilizer over the soil and rake the soil surface enough to cover the seeds.

Here are a few other tasks to focus on as we head into the fall season:

  • Rake or mow down mushrooms that come up in the lawn, but check under the mushrooms first to be sure gnomes are not hiding there. Also, don’t try to annihilate them with fungicides. The mushrooms are not harming the grass and fungicides wouldn’t have any effect anyway.
  • Bring indoors all potted herbs that have spent the summer outdoors. As with house plants that were vacationing outdoors, carefully examine each plant for evidence of insects and mites. The critters I most often encounter on potted herbs are aphids and spider mites. In most cases, a forceful spray of water will help dislodge most pests. At other times, I use a spray made by mixing one tablespoon of dish washing soap in a gallon of water or a solution of one tablespoon of rubbing alcohol in a gallon of water. A gallon may seem like a lot, but it is likely that repeated applications will be needed through the fall and winter. I use a gallon size milk carton to hold the solution and pour from that into a smaller spray bottle when applications are warranted.
  • Start a compost pile if you have not already done so. Many trees and shrubs are already shedding leaves, and garden cleanup is well underway. A compost pile need not be anything more than … uh, a pile. Just one word of caution: do not toss weeds with mature seed heads onto the pile. Unless the interior temperature of the pile reaches 140 F the seeds will remain viable. Scattering the weed seed laden compost over gardens next year will result in a weed infested garden. I have a separate compost pile where weeds and diseased plants are tossed. The compost from that pile will remain there, at least until the pile reaches the equivalent height of Mt. Greylock and then it will become a tourist attraction.

Want to learn more about sustainable food gardening? Then plan to attend the ThinkFood workshops to be held on the campus of Bard College at Simon's Rock in Great Barrington on Oct. 1 and 2. The workshops range from such topics as composting and rooftop gardening to foraging wild edible plants. For conference details and registration go to:

On a personal note: It was 49 years ago when I trekked over the state line to teach biological and environmental sciences at a local college. Soon after starting my career there I was approached to teach horticulture, a subject in which I had no formal education nor ever taught. Yes, I came from a family of onion farmers (who encouraged me to find another career) and dabbled a bit in home gardening, but to teach such a course was well beyond my expertise. To make matters worse, there were no resources available to me other than an abandoned greenhouse. Nevertheless, I agreed to do it. Needing some help, I went to a local nursery, Ward’s Garden Center, where I met Don Ward Jr., owner of the nursery. Don not only supplied me with plants to get started but was also a constant resource of information that helped immensely to get the course underway. Ultimately, it led to a career change as I moved on to UMass where I had an extremely satisfying career as an Extension Specialist in horticulture. It would not have happened without Don’s generosity, a character trait he imbued in his entire family. Sadly, Don passed away last week. If there is one thing I could say to Don, it would be: “Thank you!”

Garden Journal columnist Ron Kujawski began gardening at an early age on his family's onion farm in upstate New York. Although now retired, he spent most of his career teaching at the UMass Extension Service.