Pick Pumpkins and Winter Squash
Harvest pumpkins and winter squash before the the first heavy frost. Otherwise they can suffer chilling injury that will keep them form storing well. For the longest storage, cure these vegetables to dry and harden their shells completely. Place in a warm (75-85 degrees F is ideal), well-ventilated spot for a week or two -- perhaps near your furnace or on an enclosed porch. After curing, move to a cool, dark spot (50- 60 degrees F), such as an unheated spare room or cool closet. Check the squash and pumpkins periodically and remove any that show signs of rot.
Let Frost Sweeten Fall Crops
Kale, Brussels sprouts, and collards all taste sweetest if you wait until after light frost to harvest. But if a sudden early cold snap into the teens is predicted, cover plants, as the sudden drop in temperature may injure plants. Leaves of collards and kale are ready for picking as soon as they reach usable size. Sprouts are ready when they are about an inch in diameter. Pick off and compost yellowing lower leaves.
Harvest Green Tomatoes
Once the nights are consistently below 50 degrees F it's best to harvest any remaining mature green tomatoes (those that have turned light green to white), even if the vines haven't yet been hit by frost. These tomatoes will ripen better indoors once the weather is this cool. Clip tomatoes from the vine with a short piece of stem attached. Red tomatoes well on their way to ripening can tolerate cooler temperatures and can be left on the vine until frost threatens.
Store Cannas, Dahlias, and Gladiolus
Once frost has blackened the tops of cannas, dahlias, and gladiolus, it's time to dig them if you plan to store these bulb-like structures (actually rhizomes, tuberous roots, and corms, respectively) for planting again next spring. Dig carefully so as not to injure them, then let dry at 60-70 degrees F in a well-ventilated spot out of direct sun with the foliage attached. Cannas and dahlias need only a few days of drying, while glads need two to three weeks. Then remove foliage, brush off soil, and store in vermiculite or sphagnum moss at 40-50 degrees F.
Cover Greens for Extended Harvest
Cover beds of lettuce, spinach, arugula, and other greens with floating row covers to extend your harvest season. The row covers will provide a few degrees of frost protection, enough to often give you several weeks or more of garden-fresh produce compared to uncovered plants.