Vegetables can be divided into two general groups - cool season vegetables and warm season vegetables. Cool season vegetables are frost-hardy, thrive in cool weather, and do well in early spring. Some may be replanted in late summer and fall to take advantage of the cool fall weather and many can have their harvest extended into winter months by using season lengthening techniques (cold frames, row covers, etc.).
Warm season vegetables, such as tomatoes and peppers, are frost tender and require a warm growing season. These vegetables should not be planted outside until all danger of frost is past. They may also require ground warming techniques (black or infra-red ground covers, wall-o-water, etc.) for them to thrive in cooler climates.
The specific variety of plant selected for use should be based in part on the length of the growing season and the relative maturity rate of that variety. Varieties that develop slowly (require a long growing season) will not do well in an area with a short growing season unless season lengthening techniques are used. Areas with short growing seasons may be restricted to cold-hardy vegetables only. Seed catalogs typically provide the length of days required from seeding to harvest.
The charts below provide approximate times for the planting of vegetable seeds based on the average last spring frost and the average first fall frost.
Additional points to consider:
Transplants are typically more cold sensitive than when the same plant is directly seeded into the garden. (In my garden, lettuce has been known to sprout from seed in late February.) Transplants should be set out into the garden after all danger of frost has past or hot caps or other protective devices can be used to shelter these tender transplants from the stresses of cold weather.
|Average Frost dates for Western Washington and Western Oregon.|
|Ave. Last Frost||Apr 6||Apr 30||Apr 26||Mar 25|
|Ave. First Frost||Nov 4||Oct 15||Oct 25||Nov 13|
|Ave. Last Frost||Apr 1||Apr 9||Apr 14||Apr 3|
|Ave. First Frost||Oct 22||Oct 31||Oct 28||Nov 4|
Or check by zip code at Garden.org: Frost Dates: First and last frost dates by zipcode
|Cold-Hardy Plants for Early Spring Planting|
Hardy (plant two to four weeks before the average last spring frost)- mid-Marchasparagus
Cold Hardy crops can also be planted in the late fall for a spring crop
Not cold-hardy (plant after average last spring frost)beet
|Cold-Tender or Heat Hardy Plants for
Late Spring or Early Summer Planting
Requiring hot weather (plant at least one week after average last spring frost)- April-Maybean (snap)
New Zealand spinach
Medium heat-tolerant (good for summer planting; i.e. April-May in this area)bean (lima)
Hardy plants for late summer or fall planting (plant approximately two months prior to average first killing fall frost)- AugustBeans (Lima & snap)
New Zealand spinach
Very hardy (plant approximately six (6) weeks prior to last killing spring frost) - Late February - early Marchbeet