Northern & Central Midwest
Sow Fall Lettuce
For tasty fall greens, sow seeds of lettuce, mesclun mixes, and oriental greens. They will get off to a better start if planted in partial shade. Against usual watering advice, water greens lightly and frequently to keep them always cool and moist. Harvest every other plant so heads will develop.
Leave Seed Heads
Allowing flower heads to remain on perennial flowers will give you fall and winter interest and also feed the birds. Leave dried heads on zinnias, coneflowers, globe thistle, astilbe, black-eyed Susans, marigolds, sunflowers of all types, and cosmos. These can be removed next spring as the new growth starts.
Enjoy Fall Mums
By all means, indulge in those beautiful chrysanthemums you see flooding the garden centers. The earlier you get them planted in the garden, the better chance they will have to survive the winter. Even in the best of conditions, however, mums are not very hardy. After planting, mulch well and then mulch heavily over the winter.
Seed the Lawn
The end of August and early September is best time to seed or overseed a lawn in most areas of the Midwest. Use grass seed appropriate to your site, especially choosing for sun or shade. Cultivate the soil down to a few inches and broadcast grass seed. Cover with loose straw and keep the soil constantly moist until seed germinates.
Keep Drying Herbs
Don't forget to continue harvesting herbs until frost. Keep pinching out flowers to help the plants retain their essential oils. You can trim leaves and dry them individually, prune off stems to dry, or pull entire plants. Put them in a dark, airy spot or pop them in a food dehydrator for a few hours.