By Carl Wilson, Colorado State University Cooperative Extension agent, horticulture, Denver County
If you are planning a vegetable garden this spring, you will be interested in the results of annual vegetable variety testing at Colorado State University in Fort Collins. Your choice of adapted varieties is important. For example, cool season vegetables are always difficult to grow here because of spring temperature fluctuations. Many cool season vegetables respond to high temperatures by "bolting." When these seed stalks form, the quality of leafy vegetables, such as lettuce, suffers. Some varieties may resist bolting three or four years out of five and thus be better bets for planting along the Front Range.
Of the five Chinese cabbage varieties tested last year, 'Optiko' from Seedway delayed bolting longer than the others. In previous years, two other varieties that showed better adaption are 'Two Season' (Burpee) and 'Yoko' (Seedway). While previous tests showed two Seedway radicchio selections, 'Firebird' and 'Medusa' to be bolt-resistant, both bolted last summer.
In tests of lettuce varieties, 'Sierra,' (Johnny's), a large, flat-leafed type with a purple tinge, held longer. Though not tested, 'Jericho' from Seeds of Change, a new romaine type lettuce from Israel should be considered. It is reported to retain its sweet flavor and crisp texture better than others in hot weather. In general, romaine lettuce types hold up better than looseleaf and head types when weather turns warm.
Among warm season vegetables, 'Big Chile,' a 6-inch long pepper from Peto, stood out among eight peppers tested. The four consistently performing tomato varieties for this area are 'Big Beef' and 'Celebrity' from Peto; 'Early Girl' from Park and 'Medina' from Vilmorin.
The 49-day okra variety, 'Cajun Delight,' a 1997 All American Selection winner, tested well in Fort Collins and bears pods three weeks earlier than standard varieties.
A recent warm season vegetable development not tested, but of note, is the introduction of a short season sweet corn variety 'Yukon Chief' (55 days), a dwarf variety developed by the University of Alaska. Offered this year by Garden City Seeds, it germinates well in cold soils, is open pollinated, grows three feet tall and produces yellow kernels on five to six-inch ears. This may be worth planting in foothills locations.
For more information, contact your local Colorado State University Cooperative Extension office.
Photograph courtesy of All America Selections
© CSU/Denver County Extension Master Gardener 2010
888 E. Iliff Avenue, Denver, CO 80210
Date last revised: 01/05/2010