- Finish planting in early October. Most perennials can be divided now. All divisions and transplanting should be finished by the middle of October. Note: some perennials resent division, such as butterfly weed, euphorbia, Oriental poppy, and gas plants (Dictamnus albus).
- The ‘first frost date’ in our area refers to light frost and is often not a killing frost. October 21st is the median date for the first frost in the Maplewood/South Orange/ Union area (now Zone 7a). It is earlier (October 11th) for those areas west of South Mountain including Millburn, Summit, Madison, Morristown and points west (e.g. Glen Gardner).
- Some perennials may turn to mush quickly at this time and should be pruned, if desired. Otherwise wait for several killing frosts and prune in November. Collect and dispose of leaves affected with leaf spots, scabs and other diseases (do not compost them).
- Dahlias keep blooming until the first hard frost, maybe into Nov. especially in a protected spot. Dahlias should be dug and stored after the first heavy frost.
- Many summer annuals are spent – so go ahead, pull them out and replace them with pansies, kale and ornamental cabbages for fall interest in key locations. Reserve seeds if you want zinnias, cosmos, cleome etc to reseed next spring.
- Do NOT fertilize your ornamental plants & shrubs. Perennials are slowing down and preparing to go dormant for the winter. You do not want to encourage new growth now.
- Weed control is an on-going problem. Many weeds set seed in the fall and will create a problem for you next year. Remove weeds with as much root as possible or they will come up from roots as well as from seeds next year.
- Mulch your garden heavily with an organic mulch to slow down winter weeds and to protect the roots of your perennials from the freezing and thawing of winter.
- Some plants are prone to disease and pests, and should not be composted. Most home compost piles do not get hot enough (122 °F) to kill pathogens, so do not include anything with signs of disease or pests like powdery mildew on zinnias or blight on tomatoes or aphid-covered stems.
- Weeds that can regrow from pieces of root or stem such as morning glory, bindweed, sheep sorrel, ivy, and common artemisia
- Weeds that have gone to seed
- Over-ripe tomatoes, melons, or squash (unless you like volunteers) – their seed can sprout next year.
- Thick leaves like oak, unless you run a mower over them a few times otherwise they can mat together so water and air cannot get through.
- Fall is the best time to core aerate the lawn and to plant cool-season grasses. Aerate before fertilizing or reseeding.
- Top-dress existing turf and apply lime to the lawn now. Hold off putting down any fertilizer until November.
- Plants that thrive in the shade outdoors in the summer can be houseplants in the winter. You can pot up coleus, wax begonias and impatiens. Try to disturb the roots as little as possible when you dig them up.
- Be ready to move house plants indoors before temperatures fall below 50º F. Check house plants for signs of insects. If you find spider mites, aphids, whitefly, and scales, you will want to treat a few times, if necessary, before moving back indoors.
- While you are at it, clean up the plants by removing dead leaves and flowers, snip back over-long stems and give the plant a thorough bath with the garden hose.
- When you finish with garden clean-up, clean out and organize storage spaces and repair equipment.
- Clean birdbaths, bird feeders and fill them.
- Fall is a great time to start a compost pile. You can build a bin or simply pile all yard waste in an inconspicuous corner.