Vegetable Gardening
Washington County
Vegetable gardening in Washington County can be rewarding and successful. Locations within the county vary widely in elevation which has a significant influence on the climate and growing season. For example, St. George has an elevation of 2,624 feet and a frost-free growing season of more than six months. Enterprise has an elevation of 5,346 feet and the frost-free season begins the first week of June and ends in mid-September. Knowing when to plant is critical in areas where the season is short (about 3 ½ months).
Cold-hardy vegetables such as cabbage, onion, peas, spinach, and turnips can be planted before the danger of frost is over. This is because they can tolerate cold temperatures and they do not fare well once temperatures get into the mid-eighties and above. Other plants such as beets, carrots, potatoes, and parsnips may be planted before the last frost date but could be tender if they are out of the ground on a night when the temperatures drop well below freezing. Keep in mind that the frost-free dates given here are only average dates and will vary from season to season.
You may also consider growing or purchasing “transplants” of tender vegetables i.e. tomato, pepper, eggplant, and melons. Expose young plants gradually to the weather conditions (hardening off period) to get them ready for the garden. Then plant them outdoors after the first of April (the last avg. frost date). Transplants will take less time to mature than direct-seeded vegetables and therefore “begin to bear” before it gets too hot. However, this does not work well with all vegetables. Corn, beans, and root vegetables such as carrots and beets do not usually transplant well and should be “direct-seeded”.
Even though the season starts early and ends fairly late in the St. George area, the middle of the season is too hot to grow most vegetables successfully. There is a period beginning in June which often goes until mid-September when the temperatures exceed 95 degrees nearly every day. This extreme heat renders the pollen of most vegetables sterile and fertilization cannot take place. This is often seen on tomatoes and squash when the flowers wilt and die in mid-season rather than forming young fruits. During the hot period, areas of higher elevation and cooler average temperatures will have much better success with gardening.
Another way to garden in the St.George area is to think of it as two growing seasons. Begin early (Spring) and plan to mature vegetables before it gets really hot, and then consider planting a Fall Garden. This involves planting another crop early enough in the season to have plants come into bearing before frost (first average frost October 31). In theory, this works well on short-season crops like beans and squash but is more difficult to gauge on long-season crops such as tomatoes and melons. To be successful with Fall gardening you start with the first average frost date and count backward to see how many days you need before harvest. For example, if a vegetable needs 60 days from planting to harvest, start with the first average frost date of October 30 and go backward to August 30 to estimate your planting date. Days to harvest are on the seed packages of each type of vegetable.