Dandello's Garden - September

Priorities:

If you're planning to give pots of herbs as winter gifts for Chanukah, Christmas, Kwanzaa, or Yule, start now by potting up divisions, taking cuttings or planting seeds. Keep them outdoors till the end of the month (but keep an eye out for early cold snaps), then bring them inside to a cool but bright spot.

Year-Round Kitchen Garden:

Until a frost kills the tomatoes, peppers, basil, zucchini and beans, the vegetable garden will keep pumping out food. Harvest everything that is ready every week. After frosts arrive, there will still be greens, brassicas, and root crops to pick.
Clean up the summer garden. Compost dead and dying annuals that are disease-free. Diseased plants should go in the yard waste bin. Sow cover crops anywhere you've got bare soil. Buckwheat, annual rye and crimson clover (an annual) will all add biomass and protect your beds from too many weeds.
Dig and divide the beds of multiplier onions.
Dig up the remaining leeks that sent up flower stalks last spring. The bases will have split into several bulblets, each of which can be separated and replanted. They should be ready for harvest in late winter or early spring.
Early sweet potatoes varieties may be ready to dig by the end of the month.
Make a final sowing of leaf or semi-heading lettuce and mesclun mixes. In the warmest parts of this zone, there's still to sow some beets, arugula, corn salad, garden cress, spinach and turnips.
Get your fall vegetable garden into the ground during the first two weeks of the month. Compost the spent summer plants and sow beets, broccoli, cabbage, bok choi, cauliflower, chard, collards, kale, kohlrabi, lettuce, mustard greens, onions (sets or seeds), radishes, spinach, and turnips. Keep the seed beds moist and cool by shading and using mulch (lightly mulch over seeds and remove after germination). Broccoli, cabbage, cauliflower, and collards are probably best grown from transplants, but the rest can be direct seeded. Carrots planted now probably won't be ready till spring.

Woody and Ornamental:

Trim evergreen hedges like holly and privet at the start of the month. There is just enough time left for some new growth to cover the scars and harden before the first hard frost hits.
Fall is the best time for planting trees and hardy perennials. Autumn rains will get them established and they will growing their roots in preparation for spring all through the fall and winter,.
Do not fertilize or prune your trees and shrubs this month. You don't want to encourage new growth before the winter freezes.
Tree fruits are ripening. Get out the big pots for jam and apple sauce.

Soil and Maintenance:

This is a great time to spread compost from your home bins. Even a fairly small amount (1/2 " top dressing) benefits the topsoil by enriching microbial life.
This is also the time to check and renew your mulch. Remember to keep it away from the trunks and main stems of your plants, and don't go deeper than about 4". Water and air need to reach the plant roots.

Lawns:

With all the autumn rain, fescue, bluegrass, ryegrass and other cool climate lawns are still going strong. Keep them mowed tall, 3 to 3 1/2", so they can shade out weeds and look great. Remember to leave the clippings on the lawn - unless the grass has gotten ahead of you and the clippings clump when you mow. In that case, add the raked up clippings to your compost pile and mix well so they don't clump in the compost or use them as mulch. In mid-month, add a nitrogen-rich organic fertilizer.

Critters Good and Otherwise

Leave a few clumps of flowers (such as sunflowers) and grasses standing, if you can, after they've matured and turned brown. They are excellent sources of food and shelter for wildlife.