Keep Bulbs Cool
Spring-flowering bulbs, such as tulips and daffodils, shouldn't be planted until the soil temperature cools down to about 60 degrees F. If you buy your bulbs early, keep them cool (between 60 and 65 degrees), dry, and well-ventilated until it's time to plant. Do not store them in closed plastic bags, where moisture will accumulate; mesh or paper bags work much better.
Color Up Poinsettias
Time to start "coloring up" those poinsettias. Bring the plants indoors to a sunny window when nights cool to near 55 degrees F. Beginning the last week in September, provide 15 to 16 continuous hours of total darkness every night (cover them with a cardboard box or set them in a closet) along with 60- to 65-degree temperatures.
Stop planting and transplanting perennials about eight weeks before freezing weather is expected. This gives plants time to become rooted and established before being subjected to the freezing and thawing soil of winter. Apply several inches of organic mulch, such as bark chips, over the root area (do not cover the crown) to help prevent frost heaving, and make sure the soil is kept slightly moist until it freezes.
Cull Fall Veggies
Vegetable growth is slowing as the days shorten. This "fall factor" can add 10 to 14 days to the harvest of vegetables planted this summer. Remove any flowers and fruits of melons, winter squash, pumpkins, eggplants, and tomatoes that are too small to ripen before frost. This will help the remaining vegetables mature faster.
Give Amaryllis a Fall Nap
It's nap time for amaryllis that have been growing all summer. They need to rest, completely dry, for eight to ten weeks in a cool dry location before being put back into active growth. Once they are repotted and returned to growth, allow four to six weeks for the blooms to appear.