Biofumigation! Now that sounds like a topic you would not want to bring up in polite company. However, I suggest you forego propriety because biofumigation can be a very important part of pest and disease management strategy in the vegetable garden.
To put it simply, biofumigation is the release of volatile chemicals during the breakdown of plant materials. These chemicals have pesticidal properties, that is, they can suppress many diseases, nematodes, insects, and weeds.
The plants most effective as biofumigants include common cover crops, such as sudan grass, winter rye and mustard. I've already planted mustard in the area of the garden where peas and potatoes had grown. I chose mustard because this is where my garlic crop will be planted in late October, and mustard, specifically the varieties "Caliente," "Pacific Gold" and "Kodiak" has been shown to be effective in controlling garlic bloat nematode, recently a serious problem in garlic production. Once the mustard plants begin to bloom, I'll mow them down with my string trimmer and then till them into the soil, where the released chemicals can kill the nematodes. As with all cover crops, I'll wait two weeks before planting the garlic.
While it is a little late to get much biofumigant benefit from a planting of sudan grass — best planted in early summer — there's plenty of time left to plant winter rye. As the name implies, this rye survives the winter and needs to be tilled under in spring, again about two weeks before planting vegetable crops.
Hence, don't be shy. Biofumigate!
Don't be shy about tackling these tasks:
• Handpick stink bugs found on vegetable and fruit crops and drown them in a jar of soapy water. The most common of these piercing/sucking insects is the Green Stink Bug. As the name implies, the adult is green in color, but the immature or nymph stage is black and pale yellow. Stink bugs are plentiful this year and are damaging fruit of tomatoes, squash, cucumbers, peppers, grapes and apples. That really stinks!
• Sow seeds of basil, parsley, cilantro and other annual culinary herbs in pots for growing indoors this fall and winter. These are easy to grow indoors if given enough light. In the meantime, harvest shoots of perennial herbs, such as tarragon, thyme and oregano, and hang the stems in a dark, well-ventilated place for drying. Once you have a good supply of newly dried herbs, toss out dried herbs older than one year.
• Incorporate lots of compost or rotted manure into soil before planting peonies. Now is the ideal time to plant peonies, one of the most reliable plants in the garden. If properly planted, peonies will most likely outlast Methuselah.
• Start shopping for spring flowering bulbs. The early bird may get the worm, but the early bulb shopper gets the best selection — of bulbs, not worms. If deer and rodents have been in the habit of dining on your spring bloomers, plant more of the less palatable bulbs, e.g., alliums, daffodils, snowdrops (Galanthus species) and snowflake (Leucojum aestivum). Of course, after a tough winter, hungry deer will eat whatever plants are at hand ... er, hoof.
• Dig up summer flowering bulbs as their leaves turn yellow or when they have died back.
• Take cuttings from non-flowering shoot tips of geraniums in the garden. Cuttings should be four inches long, with each cut made just below a leaf joint. Place cuttings on a bench and cover with paper towels for a day or two to allow the cut ends to callous over. Root cuttings in individual pots filled with a sterile potting mix.