From IFAS

What To Plant:
Bedding Plants: Even though temperatures are still warm, begin planting for the
cooler months ahead. Impatiens, alyssum, and dianthus are good plants for the
fall/winter garden. See: Gardening with Annuals in Florida
Bulbs: Plant agapanthus, rain lily, and Clivia lily now for blooms next spring or
summer. Add organic matter to the planting bed for best results. See: Bulbs for
Florida
Herbs: A wide range of herbs can be planted from seed or transplants this month.
Some to try are dill, fennel, parsley, and cilantro. See: Herbs in the Florida Garden
Vegetables: Plant crops now that will grow and produce through the winter months.
This includes beet, English pea, carrot, garlic, and onion. See: Florida Vegetable
Gardening Guide

What To Do:
Lawn weeds: Control winter weeds in lawns before they appear. Pre-emergent
herbicides should be applied when nighttime temps drop to 55-60°F for several
consecutive nights. See: Weed Management in Home Lawns
Fertilize ornamental trees and shrubs: This is the last month of the year to
fertilize shrubs and trees. Controlled-release fertilizer provides nutrients over a
longer period of time. See: Fertilization and Irrigation Needs for Florida Lawns
and Landscapes
Fertilize lawns: For bahiagrass and centipedegrass lawns use a fertilizer (not a
weed & feed) that contains controlled-release nitrogen for longer lasting results.
Choose one with little or no phosphorus unless a soil test indicates a need. This is
the last lawn fertilization for the year. See: Bahiagrass for Florida Lawns
Centipedegrass for Florida Lawns
Strawberries: Prepare beds and set strawberry plants this month. Strawberries
also make a colorful and tasty container planting. Water daily until plants are
established. See: Growing Strawberries in the Florida Home Garden
Fertilize Palms: Fertilize palms this month with 8-2-12+4Mg. See: Fertilization of
Field-Grown and Landscape Palms in Florida
Oleanders: The oleander caterpillar is a year round resident in South Florida. To
control without harming beneficial insects, prune off infested leaves or spray with BT
(Bacillus thuringiensis). See: Oleander Caterpillar
Twig girdlers: Small branches falling from oak and hickory trees may be the work
of twig girdlers. To control, clean up and destroy fallen branches, which may harbor
young twig girdlers. See: Insect Borers of Trees and Shrubs

From A Garden Diary:

October

Vegetable gardening hits high gear by mid-month when the first refreshing cool fronts start to penetrate the peninsula on a regular basis. Vegetable choices include broccoli, turnips, spinach, onions, carrots, cauliflower, beets, radishes, mustard, cabbage, lettuce, tomatoes, potatoes, parsley, celery, peas, summer squash and lima and snap beans. Most herbs should be planted out now. Strawberries also can be planted. Annuals include: coleus, marigold, torenia, vinca, impatiens, salvia, portulaca, cosmos, ageratum, gloriosa daisy, celosia, verbena, wax begonia, calendula, alyssum, snapdragon, nasturtium, hollyhock, cornflower, pansy, candytuft and larkspur.

The last big fertilization of the year should be applied to all plants this month. A high quality all-purpose fertilizer should be fine for most trees. I have used Lesco 12-2-14 with good success on most plantings. Lawns benefit from a good application of Lesco 16-4-8. But any good quality fertilizer with trace elements should do the job. Apply lightly and evenly and water in after application.
The dry season begins mid-month. As soon as you can, it’s a good idea to check irrigation systems before their winter workouts. Fungal problems appear with the cooler weather, so make sure watering is restricted to the morning hours between 2 and 10 a.m. The dry season will last through May, so some supplemental irrigation will be necessary for lawns and bedding plants…