Gardening in Washington State encompasses USDA zones 4-9, a pretty big range. This means a general planting calendar for May is just that, general. If you want to know exactly what to plant in May, consult a Washington planting guide that will list your zone and the first and last frost dates for your area.
Gardening in Washington State
Gardening in Washington State is all over the map. There are arid, coastal, mountainous, rural and urban regions. Knowing what to plant in May will depend upon your last average frost. An Eastern planting calendar for May will vary greatly from one for the West side of the state.
Western Washington Planting Guide
Again a planting calendar for May will vary depending upon your location. In general for the western side of the state, the frost free growing season begins March 24 and ends Nov. 17th.
So what to plant in May in Western Washington? Because the west side of the state is so temperate, most everything will have been either direct seeded or transplanted by May. If the weather has been inclement however, May is pretty much your last chance to get transplants out into the garden other than crops like greens and radishes, which can be successively sown.
May is definitely the time to get those tender heat-loving crops outside if you haven’t already; plants like tomatoes and peppers.
Eastern Washington Planting Calendar for May
Things are a bit different on the eastern side of the state, depending upon area. There is no blanket rule of thumb. That said, a great majority of the west side of the state is the Inland Empire: Spokane and the surrounding area.
Here again, most everything will have been sown or transplanted by April, but there are some exceptions.
If you prefer to direct sow seeds, May is your month for sowing many veggies. Sow seeds for beans, corn, cucumbers, gourds, squash, pumpkins, okra, southern peas, and watermelon in the first two weeks of May.
Tender heat loving veggies like eggplant, peppers, sweet potatoes and tomatoes should all be transplanted in May when temperatures are assured. Gradually harden the plants off over the course of a week to 10 days prior to transplanting.