As summer winds down with shorter days and cooler nights, it’s time to clean up the garden and plan for next spring. Here are some steps Colorado gardeners should take in September:

Perennials, annuals and bulbs

• Plan spring bulb gardens and plant bulbs late in the month. Store bulbs in a cool, dry location until planting.

• Dig up tender bulbs such as caladium and gladiolus. Allow them to dry and then store in dry vermiculite for planting next spring.

• Fall is a good time to divide and replant perennials. This ensures time to reestablish the divisions before winter. Keep newly divided plants watered.

• Decide whether you want to remove spent flower blooms (called deadheading) or leave them as winter food for birds. If you decide to remove them, consider saving the seeds. When flowers (such as marigolds, nasturtiums, zinnias, calendula and snapdragons) have dry puffy tops or dry seed pods that begin to break open, collect seed for planting next year.

Shrubs and trees

• Continuing watering trees and shrubs through the first hard frost. Evergreens are particularly vulnerable to desiccation and winter burn if not well-watered before the cold sets in. Long, dry periods during fall and winter can injure, weaken or kill parts of plant root systems. Weakened plants might die in late spring or summer when temperatures rise and could be susceptible to insect and disease problems.

Lawn

• If you didn’t fertilize in late August, do so by mid-September.

• Attack broadleaf weeds such as dandelions, plantain, clover and bindweed while they are actively growing.

Fruits and vegetables

• Keep picking warm-season crops and herbs. Canning, freezing and drying are options for preservation.

• Add organic matter such as manure, compost and/or leaf mold to emptied garden beds to improve garden soils for next year.

• Remove and dispose of any diseased plant materials properly. Do not add these to the compost.

• Save seeds from your favorite heirloom vegetables to plant again next year. (Seeds from hybrid plants might produce a different variety in future years whereas heirloom seeds will give you “true to seed” plants).

Tomatoes: Select the fruit after it ripens but before it rots. Cut fruit and squeeze out the pulp into a container. Add a little water, and then let this ferment two to four days at room temperature, stirring occasionally. When the seeds settle out, pour off the pulp and spread seeds thinly to dry thoroughly.

Peppers: The seeds mature after the peppers have changed color. Cut open the pepper and scrape out the seeds. Dry the seeds in an arid, shaded place until they break rather than bend.

Beans, peas: Leave pods on the vine until the pod dries. Harvest the seeds before they are dispersed.

Submit gardening questions to csumg2@elpaso.com or call 719-520-7684. The in-person help desk is open 9 a.m. to noon and 1-4 p.m. Mondays and Wednesdays at 17 N. Spruce St. Find on Facebook at Colorado Master Gardeners — El Paso County.

Is it harvest time in your garden?

Debra Stinton Othitis