Spring Gardening in St. George
By Rick Heflebower, Washington County Horticulture AgentVegetable gardening in Washington County can be rewarding and successful. The county has a wide range 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 later in the spring and ends earlier in the fall (shortening the season considerably.) This doesn’t mean that you can’t grow vegetables there – you just need to know when to plant.
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.
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 August 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 deal with the heat of summer is to think of it as two growing seasons. Begin early and plan to mature vegetables before it gets really hot. You can also plant late in the season and try to have plants come into bearing late enough to miss the worst of the heat. In theory, this works well on short-season crops like beans and squash but is more difficult on long-season crops such as tomatoes and melons. You may also beat the heat by purchasing young transplants and putting them in while it is cool. Transplants will take less time to mature than direct-seeded vegetables and therefore mature before it gets too hot. However, this does not work well with all vegetables. For example, corn, beans, and carrots should not be transplanted. Some gardeners have used shade cloth or other ways to shield plants from the harsh afternoon sun. The period from 2 pm until sundown is generally the hottest time of the day. Where possible, offer protection from the sun from the west in late afternoon.
Planting Times for St. George Area
By Rick Heflebower, Washington County Horticulture AgentFEBRUARY 15 – MARCH 15
MARCH 1 – MARCH 15
MARCH 15 – APRIL 1
APRIL 1 – MAY 1
Cantaloupe and melons
FALL HARVEST/JULY 15 – AUGUST 1
ST. GEORGE HAS A GROWING SEASON OF ABOUT 210 DAYS
Last frost in Spring – April 1st
First frost in Fall – October 1st