Stormwater Calendar

Preparing Your Home throughout the Seasons 


Creek and forest with snow on the ground.

Thinking of installing a rain garden? Now is a good time to look for the areas in your yard where excess water collects. Conduct an infiltration test to determine if the soil absorbs water quickly enough. For the soil to work well, it needs to drain at a minimum of one-quarter inch per hour.

Prune fruit trees and other woody trees and shrubs while they’re dormant.


Field of pink tulips.

It’s time to clear ditches along your property. Get out on a nice day to weed eat and mow the ditches, and make sure they are clear of debris.

Design and begin planning your rain garden. Use this guide for help!

Start prepping the yard for spring!

  • Prepare new planting beds and gardens by mixing in 1–3 inches of compost.
  • Pull weeds when they first start growing, while soil is moist and roots are short, before they go to seed.
  • Buy plants that resist disease and use less water.
  • Start mowing lawn, about two inches high for most lawns; try to “Grasscycle” – leave the clippings for free fertilizer.
  • For lawns in poor condition: aerate, overseed, and top-dress with one-half inch of compost.
  • If you must fertilize, use “natural organic” or “slow release” fertilizer.


Two boys jumping off pier into lake.

If you’ve installed a rain garden in the past two years, be sure to water the garden during the dry summer months.

Summer gardening:

  • Mulch flower and vegetable beds, shrubs and trees, with compost or grass clippings to conserve water and control weeds.
  • Mow regularly and leave the clippings on the lawn; keep mower blades sharp to reduce lawn damage and brown tips.
  • Consider saving water by letting some lawn areas (ones that don’t get heavy traffic) go brown and dormant until fall.
  • Water at dawn or in evening to reduce evaporation.
  • Need to remove knotweed? Rent an injection gun from King County. When identifying knotweed, look for zigzag stems with green heart-like or shield-like green leaves. Knotweed blooms August through September and has creamy white flowers that look like clustered “spikes.” Spikes are approximately 10 cm long.


Child in red boots walks through puddle.

Check storm drains in front of your home and clear debris, including pine needles and leaves. This will reduce the likelihood of your street flooding during heavy rainstorms.

Early fall is a great time to install a rain garden.

Fall gardening—not just closing up shop:

  • Early fall is also a great time to plant native plants and trees. The rainy season will help plants get established!
  • Same goes for new lawns. Plant September 1—October 15 to give them the best start before next summer.
  • Improve thin areas of lawn in September—October by aerating, overseeding, and top-dressing with compost. If necessary, fertilize lawns with “natural organic” or “slow release” fertilizer in September to develop healthy roots and crowd out weeds.
  • Prepare new planting areas by mulching in compost.
  • Pull emerging weeds in beds when ground is moist and before they develop deep roots.
  • Mulch garden beds with leaves or compost to reduce winter weeds and feed the soil. Or plant winter cover crops in open beds; mulch tree and shrub beds with leaves, wood chips, or bark.