Timely Tips

What to Do in October 2026
Weekly Gardening Timely Tips from
Cornell Cooperative Extension of Westchester County

Oct. 25 – 31

Perennials: Continue planting spring flowering bulbs. Wait until the ground freezes to mulch perennials planted this fall. This will help to keep the soil from heaving during a winter thaw and exposing the roots to drying out in the cold air. Leaving the ground open until it freezes may also discourage voles from burrowing in loose soil under the mulch.

Flowers: Remove tender annuals as they die back. Many of our annuals are perennials in warmer garden zones. Cuttings should be taken while the weather is still warm. If you didn’t get to this, you may pot up pest-free scented and zonal geraniums, plectranthus and others that have stood up to a bit of cold weather if you can gradually acclimate them to indoor conditions.

Fruits and Vegetables: Harvest winter squash before the first hard freeze. Brussels sprouts, collards and kale taste sweeter after a few frosts. Some root crops, including carrots, leeks, parsnips and onions may be left in the ground and dug up as needed, even after temperatures dip. Cover with enough mulch to keep the ground from freezing, and they’ll be ready as needed.

Trees and Shrubs: Hardy plant roots continue to grow until the soil temperature drops below 40°F. In the warmer sections of the lower Hudson Valley, this could be as late as mid-December. Plant deciduous shrubs while there’s another six to eight weeks for the roots to begin to become established, even if this is done after they’ve dropped their leaves.

Lawns: Keep up with fallen leaves. If you don’t have a mulching mower, rake and remove leaves from the lawn so they don’t smother the grass. If you have a mulching mower, try to mow before leaves really accumulate or get wet and mat down. If leaves don’t disappear into the lawn, rake and add them to a compost pile. Shredding leaves first will help them to break down more quickly.

Houseplants: If you saved last year’s poinsettia to try to get it to rebloom, it will need at least 14 hours of total darkness at night for roughly 8 weeks at this time of year to initiate flowering. If the plant is in a well-lit room until late at night, cover it each evening with a black contractor bag or other bag that excludes all light. Remove the bag in the morning and keep the plant in bright light during the day. Once the bracts color, keep the plant cool until flower buds appear. These plants like a cool room, 55° to 60° F. Water when the top inch or so of the planting mix feels dry.

General: Consider leaving some plants standing this fall to help shelter butterflies that overwinter in our region. If fallen leaves are not visible or unsightly, allow some to remain as protection for caterpillars nearby.

Invasive spotted lanternfly (SLF) adults are laying eggs. The insects are especially attracted to tree of heaven and grape vines, but their eggs can be deposited on many surfaces in addition to trees. If you live in, plan to travel, or have recently returned from a place where SLF is established, be sure to check your vehicle and any items kept outdoors for hitchhiking lanternflies or their eggs, and remove all before traveling (a flashlight and mirror may be helpful in hard to see spaces).

Last updated October 24, 2026