For the first time in several years of successful raised bed gardening, my small chard plants (from seed) are being chopped off at the soil line. Is the damage due to cutworms? How can I avoid and get rid of these pests? Should I replant? I don’t have any other space to plant the chard and I’m accustomed to having a large crop. Also, is it possible to establish raised beds on top of a septic field if I line the bed with contractor grade plastic before I put the dirt in? This would give us some more garden space which we need. The septic field area is the one place that is flat and receives the best sun!!!
Thanks so much,
Carmen, Bakersville, NC
Yipes! It does sound like cutworms are the problem. They usually chew through stems at ground level and can eat the whole baby plant. Oftentimes, cutworm damage is more prevalent in wet springs when planting is delayed, and they are generally most damaging in May and June. Cutworms are about 1 ¼ inches long, plump, soft-bodied and smooth. They curl up tight when you disturb them. They hide under soil clumps during the day and are active at night. In daytime you might catch them by digging around below the soil surface near your plants. Sometimes at night you can find them with a flashlight. If you find one, just drop it in a jar of soapy water. Sorry, that is fatal!
The usual advice for fending off cutworms is to install a tubular cardboard collar around transplants. These should be pushed at least an inch or more below the ground and stand taller than the transplant. You can use a cardboard paper towel or toilet paper roller, or fashion a collar with similar dimensions out of scrap cardboard.
Other ways to improve you chances against cutworms are: Keep down broadleaf weeds and grasses in the area all year and especially in the fall: that’s where the cutworm moth lays its eggs. Many cutworm larvae overwinter on crop residues and clumps of grass. If you are preparing a new bed where sod was, it is recommended that you cultivate the area in early fall and keep it weed-free until planting time in spring. Regularly hoe lightly near the plants to expose the worms to birds or toads. Prepare your garden bed about 2 weeks prior to planting, removing all residue from soil surface. Plant beneficial insect plants like Fennel, Dill, and Queen Anne’s Lace near the garden to provide habitat for some of the predators and parasites of cutworms. Some people apply bait formulations to the soil, such as a mixture of rolled oats with molasses and Bacillus thuringiensis var. kurstaki with mixed results.
Since you have no other place to plant your chard, I would clear your bed of all residues and then cultivate the soil, destroying any cutworms as you expose them. Leave the bed clean for 10 days and then replant. Start your transplants while you are letting the soil lay. Install cardboard collars at the time of planting.
As far as planting over a septic field, it is not recommended. It is best not to compromise your septic field with roots or by compressing the soil above the field. Also there would be some concern of plant contamination by the septic fluids. Consider saving your sunny garden space for plants that absolutely require full sun. Plant vegetables that will accept some shade in your sunniest shade areas (such as lettuce, spinach, greens, garden peas, kohlrabi, and even cucumbers). Alternatively, see if you could shorten hedges, remove branches or even entire trees to attain some sunnier growing areas. Scout out pools of sun in your yard or flowerbeds that could accommodate vegetables. Most vegetables are beautiful plants, and we humans have a special fondness for food-bearing plants since eating is one of our primary pleasures.
Banish the cutworms and enjoy that chard Carmen!
Ask Ruth © 2013 Ruth Gonzalez & Organic Growers School
Author: Ruth Gonzalez
Ruth Gonzalez is a former market farmer, gardener, and local food advocate who wants to see organic farms proliferate and organic gardens in every yard. She serves on the Organic Growers School Board of Directors, and in her job at Reems Creek Nursery, Ruth offers advice on all sorts of gardening questions, and benefits daily from the wisdom of local gardeners.