Tip Sheet #5
Edible Gardening

The Master Gardeners of King County maintain about 14 Demonstration, Youth or Outreach gardens. Many of these feature vegetable and fruit growing. Harvests are normally donated to local food banks. Visit us during the growing season to get ideas of what to grow and best techniques. A list of our gardens, including descriptions is available at: Demonstration Gardens.

Local organizations, including those that focus on fruit gardening include the Western Washington Fruit Research Foundation, NWfruit.org, who teams with WSU Mount Vernon, MtVernon.wsu.edu. Their fruit demonstration garden in Mount Vernon, north of Seattle, is open to the public daily, dawn to dusk.

Seattle Tilth (now Tilth Alliance) demonstration gardens are in Seattle (Wallingford, Rainier Beach and Mt. Baker neighborhoods), Kirkland and Auburn.

Seed packets often cite “frost date” in advising when to plant vegetables and flowers in the spring, so it helps to know that date for your specific location. Fall frost dates are useful for harvesting some vegetables and deciding when to move tender perennials inside. Frost dates vary by location in Puget Sound and are influenced by proximity to bodies of water, elevation, proximity to urban areas and other factors. WSU weather stations in Seattle (at the UW Center for Urban Horticulture), Woodinville (21 Acres), Snohomish and Puyallup have recorded the following frost-date ranges since 2012:

This and more weather data are available at WSU website: weather.wsu.edu. Data include soil temperature, another important consideration in planting time, especially for heat-loving crops such as tomatoes and peppers.

With our mild climate in Puget Sound it is possible to circumvent frost dates and inclement weather and grow edibles year-round with the use of season-extending devices such as cloches, cold frames and other techniques. Two useful books on this topic by Pacific Northwest authors are:

• Cool Season Gardener: Extend the Harvest, Plan Ahead, and Grow Vegetables Year-Round by Bill Thorness (2013) and
• Winter Gardening in the Maritime Northwest: Cool Season Crops for the Year-Round Gardener by Binda Colebrook (2012), available at regional bookstores and libraries. Even without the use of season extenders, crops such as carrots, beets, salad greens and kale can be planted in midsummer to harvest in fall and winter.

Another excellent reference for year-round gardening is Seattle Tilth’s “Maritime Northwest Garden Guide” (2014), available to order at their Tilth Alliance Marketplace or at their offices in the Wallingford district in Seattle.

There are four important things to consider when deciding where to plant: sun, soil, water, and access. Most vegetable crops need 5 to 6 hours of direct sunlight a day. Soil can be improved with compost; consider having your soil tested so you’ll know better what amendments to add. Watering is key so you’ll want a watering spigot nearby or adequate hoses to reach. You’ll want to be able to easily access your garden so tending and harvesting is less of a chore.

It depends. Starting with seeds has many advantages: You’ll find a far more extensive choice of varieties. Some plants such as root crops don’t transplant well and must be started from seed in the garden. It can also be cheaper to start from seed. However, many gardeners find that buying starts of warm season plants such as tomatoes, peppers and eggplant makes more sense because seeds of those plants need to be started indoors with adequate light and warmth. Also, a gardener is likely to use up an entire packet of lettuce in one season but unlikely to need an entire packet of tomatoes.

Each spring, King County Master Gardeners host plant sales that include vegetable starts at several venues. Please see Master Gardener Foundation of King County for dates and locations.

Seattle Tilth also hosts edible plant sales. Farmers markets often sell vegetable plant starts; Seattle location listings can be found at Seattle Neighborhood Farmers Markets. A broader regional listing can be found at Greater Seattle on the Cheap Farmers Markets.

Local nurseries throughout Puget Sound are a great resource for edibles gardening, from seeds to plant starts, season extenders to gardening advice.

Additional Master Gardener Tip Sheets, including “Gardening Websites” and “Gardening Publications” are available at Tip Sheets. Also, see WSU’s “Gardening in Washington State” and free downloads of WSU gardening publications at WSU Extension Publications Store.