Here are some fall garden tips from James Quinn, retired horticultural specialist.
Vegetables
Direct seeding in early September of greens and lettuces will still provide good results, but it is really too late for carrots or the transplanting of cole crops. Short season crops like turnips, Napa cabbage and baby bok choi may still finish. Be sure to thin root crops, cabbage or anything you want to "size up." To establish spinach for overwintering, plant it by the end of September.
Pinch off any young tomatoes that are too small to ripen. This will channel the energy into ripening the remaining full-size fruits. Before frost, harvest any tomatoes breaking color or that are green, mature tomatoes. Store at 55-70 degrees or a bit warmer for faster ripening. Mature green tomatoes should approach normal size and have a whitish green skin color. Keep mature green tomatoes for three to five weeks by wrapping each tomato in newspaper and inspecting for ripeness weekly.
Harvest winter squash and pumpkins before frost. For best storage quality, leave 1-2 inches of stem on each fruit. Remember to dig sweet potatoes before a bad freeze. If the vines get frosted, clip them off the next morning, as frosted vines will impart an unpleasant flavor. Pinch out the top of Brussels sprout plants to plump out the developing sprouts. Sow cover crops such as winter rye after crops are harvested or use oats if you want the cover crop to be killed through the winter.
Fruits
Pears ripen in August and September. Pick pears before they are fully mature and store in a cool, dark basement to ripen. Unlike apples, most pear varieties do not ripen nicely while still on the tree. Pears that are allowed to become too mature or to ripen on the tree develop a coarse, mealy texture and often have core breakdown. To tell if a pear is mature, a general rule of thumb is that, while still on the tree, most mature, ready to ripen pears will usually detach when "tilted" to a horizontal position from their usual vertical hanging position, but Bosc pears always are difficult to separate from the spur.
Flowers
With the arrival of October, consider planting spring bulbs among hostas, ferns, daylilies or ground covers. As these plants grow in the spring, they will hide the dying bulb foliage. Cannas and dahlias can be dug when frost nips their foliage. Allow the plants to dry under cover in an airy, frost-free place before storage.
Lawns
If you like a dense cool-season lawn with good color, consider aerating your lawn. Fall is an ideal time to do this. Aeration opens the soil surface for better nutrient and water movement. It is a practice that also helps to reduce compaction and thatch by spreading soil plugs on the surface. Soil plugs crumble and fall freely into aeration holes as well as into the thatch layer where soil microbes can feed on thatch debris. If desiring to over-seed, do so after aerating.
Aeration equipment can be found at local rental stores or garden centers. Machines that pull a half inch diameter plug 3-4 inches deep on 3- to 4-inch centers do an excellent job. Machines that force hollow tines into the soil are better than pull-type drums with spoon tines.
Power rakes are an excellent piece of equipment to prepare seedbeds prior to over-seeding. While the entire lawn may not need over-seeding, working thin areas with a power rake will create a fine seedbed to improve seed/soil contact, therefore improving seed germination.
Herbs and perennials
Seeding arugula and coriander/cilantro in September has a bonus: They won't bolt until the spring. While arugula doesn't always survive the winter (and would likely be hot and bitter anyway), I have been surprised at how well cilantro does. Watch out for the first cold nights. Basil leaves will be killed with a frost or freezing and develop chilling damage at temperatures around 40 degrees. If you haven't tried making pesto before, this is a great opportunity to use all those leaves before the cold gets them.
If you want to dry some leaves of herbs, most should still have good flavor in September, when we're still having warm temperatures and good sunlight. For best results, use a food dehydrator. I have seen techniques described with an oven or microwave, but the temperatures are too hot or variable. The optimum drying temperature for herbs is 105 degrees.
Most perennials and perennial herbs respond well to being dug and relocated in the fall, October being ideal. Splitting/dividing can be done at this time as well.
Happy gardening!
Peter Sutter is a life-long gardening enthusiast and a participant in the MU Extension's Callaway County Master Gardener program. Gardening questions can be sent to [email protected]