Early October is a good time to plant spring-blooming bulbs so they will establish roots before the first hard frost. Design your garden to display clumps of color (6 or more bulbs per clump) with the taller varieties standing in back of smaller ones. Think about planting bulbs that bloom at different times so you will have continuous color in the garden next spring.
Just as you finish setting out your spring-blooming bulbs, it will be time to think about digging and storing the tender bulbs, corms, and roots (cannas, dahlias, gladiolus, and tuberous begonias) that you planted in the spring. Once the first frost has discolored the foliage, dig out the bulbs, clean off the excess soil, and store them in a box of sawdust, peat moss, or vermiculite in a cool dry place until spring.
Remulch landscape beds. Perennials can be cut back and annuals can be removed to reduce the number of obstacles to work around.
Bare-root roses establish well if planted in early October.
Bring geraniums indoors in mid-October. Prune this year's stem back to three buds from where it grew out from last year's growth, repot (be sure to check the leaves and root ball for insect pests), and place the plants in a cool, well-lit room for the winter.
Watch your thermometer on colder nights. A windless, cold, clear night usually means a killing frost, but you can keep your chrysanthemums and asters blooming for a while longer if you provide a little frost protection for them. A small, simple frame covered with cheesecloth or an old bed sheet placed over your plants on frosty nights can add weeks more of garden blooms. Don't forget to remove the cover as soon as the frost danger has passed!
Christmas cacti need special care now to get its beautiful flowers this December. Buds will form at 50–60°F. or if the plant is exposed to at least 13 hours of complete darkness each night.