Determining when to plant a garden can be somewhat confusing in Utah’s unpredictable, varied climate where last-frost dates can vary by many days within just a few miles. Many experienced gardeners have planted at one point and later lost the plants to frost.
An example of how fickle Utah’s climate can be is in Cache Valley. Frost-free days vary from an average of 113 days in Lewiston and Trenton to 158 days on the USU campus. Similar examples occur across the state. Although exact last-frost dates are not available for all areas, a person can still determine when to plant. Often, the best thing to do is chat with a local farmer or experienced gardener in the area.
Consider the geographic characteristics of where you live. When a yard is located in a populated area or on a mountain bench, it usually has a longer growing season. Other areas located at slightly lower elevations, where cold air drains and cannot escape, have a shorter season due to the increased cold air. This is why local commercial orchards are generally located on benches. Additionally, urban and suburban areas are slightly warmer than surrounding areas due to the urban heat effect. Heat from buildings and warmth generated by sunlight reflected from roads and other surfaces increase temperatures and delay frost.
In addition to knowing frost information, a wise gardener takes into account the needs of the plants. Vegetables planted locally fall into four basic categories: hardy, semi-hardy, tender and very tender. Depending on the category, planting dates vary from early spring until early summer. Consider the following:
- Hardy vegetables, including asparagus, broccoli, cabbage, onions, peas and spinach, can be planted as soon as the soil is workable in early spring. This usually ranges between 45 and 60 days before the average last frost. These same vegetables can be safely planted until the date of the average last frost.
- Semi-hardy plants, such as beets, carrots, lettuce and potatoes, can be planted one to two weeks after the hardy group. These can be planted until the average last-frost date.
- Tender vegetables, such as celery, cucumbers, corn and most beans, should be planted on the average last-frost date in your area.
- Very tender plants, such as squash, beans, melons, tomatoes, eggplants and peppers, should not be planted until at least a week after the average last frost has passed. Even if frost does not occur before this time, these plants will not grow well and are more susceptible to disease until warmer weather.
If you have lost plants to frost, you are not alone. It is often due to Utah’s fickle weather, and all gardeners can do is try again.
Frost Information for Various Locations in Utah |
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Frost Dates |
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|
City |
Last |
First |
Frost-Free Days |
Alpine |
May 20 |
September 30 |
136 |
Blanding |
May 13 |
Oct 12 |
153 |
Cedar City |
May 10 |
October 5 |
148 |
Delta |
May 17 |
September 28 |
134 |
Farmington |
May 5 |
October 10 |
158 |
Fillmore |
May 16 |
October 4 |
140 |
Huntsville |
June 11 |
September 9 |
89 |
Kanab |
May 7 |
October 20 |
166 |
Lake Town |
June 15 |
September 10 |
87 |
Logan |
May 14 |
September 25 |
135 |
Morgan |
June 6 |
September 11 |
98 |
Moroni |
June 1 |
September 18 |
109 |
Ogden |
May 1 |
October 24 |
176 |
Park City |
June 9 |
September 1 |
92 |
Price |
May 12 |
October 7 |
148 |
Roosevelt |
May 18 |
September 25 |
130 |
Spanish Fork |
May 1 |
October 13 |
165 |
St. George |
April 6 |
October 28 |
205 |
Tooele |
May 7 |
October 14 |
159 |
By: Taun Beddes and Julene Reese - Apr. 26, 2013