Introduction to the Overwintering Onions Report (1987)

Overwintered vegetable crops, planted in July through October and harvested the following spring, offer several advantages to both fresh market and traditional row crop growers.

The first is that these crops provide possible alternatives to winter grains and spring-seeded row crops. Market prices for vegetables are ofter higher in spring and early summer than later in the season. A second advantage is that these crops are often planted late enough and harvested sufficiently early to allow three crops in two growing seasons. A third advantage is the low irrigation requirement and the absence of foliar-feeding insects for much of the growing season.

Disadvantages include possibly increased costs for fertilizer and weec control, and the risk of crop failure caused by freezing or flooding.

We have accumulated seven years of experience growing overwintered onions at the North Willamette Station and also have looked at other possible crops, including cauliflower, shallots, leeks, cabbage, spinach, and Brussels sprouts. This report deals with our experiences with onions, shallots, and leeks. The approach has been to find varieties suitable for our climate and markets, then determine planting dates and probable harvest dates, and finally to work out cultural problems associated with each crop. The most common problems encountered are: 1) adequate plant growth in the spring, usually a soil fertility-temperature problem; 2) weed control; 3) diseases related to high moisture, low-temperature conditions; and 4) premature seed stalk formation (bolting).

A full-time program of vegetable crop research has been conducted at the North Willamette Experiment Station since 1976. The Station, a branch of the Oregon State University Agricultural Experiment Station, is just north of Aurora, a historic farming community 20 miles south of Portland, Oregon. The land is provided by Clackamas County, with facilities owned by the university. Major vegetable research emphasis is on the needs of fresr market growers in the Willamette River Valley, but research is also conducted on processed vegetable crops and home garden and small farm-intensive vegetable culture.

Many of the trials reported here involved cooperation with research and Extension Service colleagues in the Oregon State University system and with area vegetable growers. The contributions of Drs. T.L. Jackson and N.S. Mansour, in particular, are gratefully acknowledged. The financial support of the Northern Willamette Valley Horticultural Society and the Plant Food Association was essential to completing these projects and is greatly appreciated.

DISCLAIMER: The use of trade names does not constitute an endorsement by the Oregon State University Agricultural Experiment Station. Always check pesticide labels for currently registered uses.