Maintenance Calendar – September

Maintenance Calendar

Compiled by Linda Lee,
WSU Master Gardener


January | February | March | April | May | June | July | August | September | October | November | December


~ September ~


  • This is your last chance to sow cool season crops for fall and winter salad crops, including arugula, leaf lettuce, mustard greens, radishes, and spinach.
  • Now into November is the best time to set out trees, shrubs, ground covers and many perennial plants. It is not a good idea to plant in heavy rains or when the ground is frozen.
  • Start or over-seed lawns. A good perennial rye mixture for the Northwest is the best seed to use. Use a winterizing lawn food with a 21-5-5 mixture. This will give it the nourishment to withstand any type of weather. Never walk on the lawn when it is frozen.
  • Bins of spring blooming bulbs begin to appear around Labor Day, such as anemones, crocus, daffodils, freesia, hyacinths, and tulips.  Select plump and firm bulbs and plant them immediately. For the best show, try to pick bulbs thatulipst bloom at different times or plant them in two-week intervals. This will give you a continuous bloom for a longer period of time. Plant them in swaths of one color melding into another color. Planting crocus bulbs in the lawn is fun. Your lawn becomes a colorful quilt and it’s a good excuse to put off that first mowing.
  • Now is the time to care for your roses. Allow a few flowers to fade on the plants and form hips late this month. This encourages the plants to head into dormancy. Hips are handsome in fall and winter, and many birds like to feed on them.
  • Clean your greenhouses before cold weather arrives. Empty old soil from flats and seedbeds, hose down the greenhouse, replace broken glass and cracked weather-stripping and check heating and watering systems.
  • Dig and divide perennials that have finished their bloom cycle. Use a sharp knife or spade to divide the clumps into quarters. Replant the divisions in weed free, well amended soil. Share with friends and neighbors the divisions you don’t have room for.
  • compostMake compost. Start a new pile or bin with grass clippings, spent annuals, prunings and vegetable scraps. Keep piles well soaked but not soggy to speed up decomposition in hot weather. A mix of one part green (grass clippings, fresh cut annuals, kitchen scraps) to two parts brown (dead leaves, chopped twigs, shredded papers etc.) will keep your compost cooking.
  • Weed around plants thoroughly. A 2″ layer of organic mulch will help keep the moisture in the soil during our usual indian summer period. After the first hard frost a deeper layer can be added or the plants can be covered with evergreen boughs, pine straw, bark etc.
  • Annuals can be coaxed into another round or two of blooms. Keep snipping off faded blossoms and feed plants with a liquid fertilizer. Those that are beyond help can be tossed in the compost unless they are diseased. In this case, they should be put in the trash.