Fall comes knocking on everyone’s front door Sept. 22. It’s time to get your green thumbs set for a season of planting, pruning and preparing. Here’s how to make the most of your autumn outdoor space:

• Tree time: It’s prime time to welcome new trees and shrubs to the landscape — their roots will have a strong start when planted this time of year. Be sure you have enough space for your addition; that includes width and height.

• Lovely lawn: Fall is your golden ticket for planting grass seeds. Till that soil, sow those seeds and give them a few gentle waterings each week.

• Harboring herbs: Don’t let the frost claim your culinary herbs. Dig up chives, rosemary, parsley and thyme, pop them in pots, and transport them inside for fresh flavors all winter.

• Homecoming for houseplants: Your indoor plants appreciated the fresh air, but they’re starting to feel the chill. It’s time to transition them back inside. Make sure the plants you bring on are not infested with aphids or mites.

• Power of perennials: Give perennials a new lease on life by dividing and replanting them.

• Unforgiving frost: Keep a watchful eye on those forecasts. Harvest tomatoes before the first killing frost; pick them and let them ripen indoors (away from direct sunlight).

• Champions of cool: Brussels sprouts and parsnips actually get sweeter after a frost — so harvest them after that first chill.

• Apple doesn’t fall far: Don’t invite problems to the garden. Clean up and remove any fallen fruit to keep pests away.

• Annuals, don’t say goodbye: Take cuttings from plants such as begonias and geraniums, plant them in pots, place them inside near a sunny window and enjoy their beauty.

• Seeds can save: Have a special flower? Save those seeds. Completely dry the seeds and store them in sealed containers for a colorful surprise next spring. Seeds might not yield exact duplicates.

• Supersize your soil: Give your garden soil a boost by adding aged manure and/or compost. Organic matter equals happy plants.

• Luxurious lawn: Is your lawn feeling squished? Aerate it to help those roots breathe. And if you’re wondering about fertilizer, you might consider getting your soil tested to see exactly what it needs.

“By all these lovely tokens September days are here. With summer’s best of weather, And autumn’s best of cheer. But none of all this beauty Which floods the earth and air, is unto me the secret which makes September fair. ‘Tis a thing which I remember; To name it thrills me yet: One day of one September. I never can forget.” — Excerpt from “September,” a poem written by Helen Hunt Jackson. Originally printed in Poems (Roberts Brothers, 1892).

Submit gardening questions to csumg2@elpasoco.com or call 719-520-7684. The in-person help desk is open 9 a.m.-noon and 1-4 p.m. Mondays, Wednesdays and Thursdays. Visit elpaso.extension.colostate.edu and register for upcoming classes at epcextension.eventbrite.com.