Time to sow seeds of snapdragons, dianthus, pansies, and other winter flowers in flats for planting outdoors during October.
Dig and divided spring flowering bulbs and perennials such as daffodil, iris, daylily, ajuga, liriope, and canna.
Plant leaf and root vegetables such as broccoli, cabbage, cauliflower, radish, spinach, and lettuce late in the month.
This month or early next month, sow seeds of wildflowers into weed-free, well-tilled soil.
Sow or overseed cool season grasses such as fescue and rye, but remember, if you apply any pre-emergent weed killers to your lawn, newly applied grass seed will not germinate.
Rejuvenate heat-stressed geraniums, petunias, begonias, and chrysanthemums for the fall season by lightly pruning and fertilizing them.
Remove weak, unproductive growth from roses to stimulate new growth for fall beauty.
Prune out dead or diseased wood from trees and shrubs. Hold off on major pruning until mid-winter. Pruning now will stimulate tender growth that may be damaged by frost.
Root prune established trees and shrubs that you intend to move this winter. This allows them to establish new roots within the zone of soil that will eventually be moved with them. Do not cut any taproots at this time.
Caladiums require plenty of water at this time of year if they are to remain lush and attractive until fall.
Don’t allow plants with green fruit or berries to suffer from lack of moisture. Hollies will frequently drop their fruit under drought conditions.
Prepare the beds for spring flowering bulbs as soon as possible. Incorporate organic matter to improve drainage to prevent the bulbs from rotting when planted next spring.
Fertilize and groom verbenas, perennial salvias and lantanas by lightly pruning and removing non-vigorous growth to stimulate a long and productive fall season.
Article source: http://ktep.org/post/september-gardening-tips