JANUARY 27, 1997
Gardening: Browsing through catalogs for a dream garden
by WSU Cooperative Extension Office
After a rigorous storm barrage in December, many gardeners are content to contemplate gardening, but not to get wet, cold, or tired. Browsing through catalogs is a fine way to experience the ideal garden, as we look at photos and descriptions of flawless flowers and perfect vegetables. In catalogs, the garden always produces abundant, exciting crops with never a disappointment. And so it will, always, in our fertile gardening imaginations!
To prevent disappointment when we actually get outside to plant, it's important to select garden varieties that will grow best in the challenges of the maritime Puget Sound climate. "Challenges" aren't only the ferocity of occasional storms, but also the predictability of unusual summer growing conditions during the garden season from April through October.
Let's start with edibles. Cool nights and cool days are refreshing for life in the summer Northwest. Very few of us feel the need for air conditioned homes! But many crops that we enjoy, such as succulent peaches, watermelon, and big beefsteak-type tomatoes grow best in hot, hot weather. How, then, can we get the best garden yield on tomatoes, corn, peppers, and eggplant, all heat lovers?
First, choose vegetable seeds or plant cultivars that are adapted to cool summer temperatures. Plant hybridizers and commercial seed producers have recognized the problems of cool climates. To choose the seeds that will do best, select from catalogs produced locally or those that recognize cool-season summers. If you do select from a catalog with national distribution, remember that the indication of "Days to Maturity" for vegetables may be too low by up to 50 percent, depending on garden conditions. for instance, a "Yellow Crookneck" summer squash, which is noted as maturing in "50 days" from planting in one national catalog, may take 65 or 70 days in the coolest parts of the maritime Pacific Northwest.
Farmers rely on a simple weather measurement called "Accumulated Heat Units." It's revealing to note what this tells gardeners about conditions west of the Cascades. To figure the Accumulated Heat Units, or AHUs, keep track of the daily mean temperature between April 1 and October 31, an average growing season for edibles. If the temperature exceeds 50 degrees on a day, the AHUs are calculated as degrees over 50. For instance, a mean temperature of 55 F. would yield AHUs of 5 for the day, that is 5 over the 50 degree mark.
How this relates to crop success is simple. Most crops require a specific ideal minimum of AHUs for productivity. On average, the AHUs in the Seattle area are only about 1800 per growing season; in the Bellingham area, they are only about 1330. To put this in perspective, Pasco in eastern Washington has an average of about 2600 AHUs even though they have many fewer frost-free days than Seattle. To ripen many grapes, for instance, AHUs of over 2200 are a necessity. Variety choices are the key.
Tomatoes, for instance, one of the most popular vegetables for home gardens, can resist ripening unless the plant choice is adapted to cool conditions. A few that have been proven to taste good and produce well are "Stupice," "Oregon Eleven," and "Fantastic." Cherry tomatoes ripen well here and many gardeners do well with "Sweet Million" and "Sweetie."
Other challenges face maritime Northwest vegetable growers. Soil temperatures are often cool-or cold-very late into the summer. Many seeds, such as tomatoes, peppers, and squash, will not germinate well in soils with temperature below 70 degrees. And many tomatoes won't set any fruit if nighttime temperatures drop below 50. The combination of cool soils and low Accumulated Heat Units makes growing a green golfball-sized tomato more probable than growing a 1 pound juicy red one.
Growing seedlings indoors for heat-loving crops is an essential step to getting good yields-but don't start too early. Select a date about 6 weeks, at most, before you intend to set tomato or pepper plants out in the garden. The King County Master Gardener Demonstration Garden planners, in Bellevue, set their tomatoes outside into the garden during the last week of May or the first week in June to get the best growing conditions. Many gardeners also shelter heat-loving crops with cloches made of plastic or other materials to guarantee best results.
A cheerful sidelight to the difficulty of growing warm-weather crops is that gardeners in this area can grow cool-weather crops nearly year-round. Greens of all sorts from lettuce through spinach, chard, kale, and endive, do beautifully and produce well. Succession plantings of greens can keep maritime northwest salad bowls filled throughout the summer, when spinach in hot-weather areas has long since bolted and stopped performing.
Check with local nurseries and locally-produced catalogs for more information on specific varieties. Here are a few catalogs: for vegetables, Territorial Seed, Cottage Grove, Oregon, 1-503-942-9547; or Abundant Life Seed Company, Port Townsend, Washington, 1-360-385-7455. For fruit, Raintree Nursery, Morton, Washington, 1-360-496-6400. (Listings are for information only and do not imply endorsement of the catalogs.)
Visit WSU's Agriculture Site on the World-Wide Web at http://www.cahe.wsu.edu.