Plant now to beat the heat! Tips for successful spring gardening in Washington County

Stock image | Photo by Baks/iStock/Getty Images Plus, St. George News

FEATURE — Vegetable gardening in Washington County can be rewarding and successful.

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Julia_Sudnitskaya/iStock/Getty Images Plus, St. George News

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-80s 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 midseason rather than forming young fruits. During the hot period, areas of higher elevation and cooler average temperatures will have much better success with gardening.

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as3d/iStock/Getty Images Plus, St. George News

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 enough 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 p.m. until sundown is generally the hottest time of the day. Where possible, offer protection from the sun from the west in late afternoon.

Want specific tips on gardening for your neck of the woods?

Contact your local county Utah State University Extension office to access resources for planting, fertilizing, watering, harvesting, soil sampling, food preservation and more!

USU Extension provides research-based programs and resources with the goal of improving the lives of individuals, families and communities throughout Utah. USU Extension operates through a cooperative agreement between the United States Department of Agriculture, Utah State University and county governments. Program areas include agriculture and natural resources; home, family and food; gardening; and Utah 4-H and youth.

Written by RICK HEFLEBOWER, Utah State University Horticulture Extension Agent.

This article was originally published in the Spring 2019 issue of HEALTH Magazine.

Copyright © Southwest Utah Public Health Foundation, all rights reserved.

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