Larry Sagers Horticultural Specialist Utah State University Extension Service Thanksgiving Point Office © All Rights Reserved
This year, like many others brings the age-old question from gardeners of when can I plant and not have to worry about the frost.
Predicting the weather more than a few days in advance is very difficult. About the best you can hope to do is to look at long-term averages. Weather is just like the stock market; history is no guarantee of the future. Each season is different and averages mean some years dates are earlier and some years they are much later.
The easiest way to get information on specific microclimates in our area is to log onto http://climate.usu.edu/utahclim/freeze/
On that site, you will find the freezing temperature table that follows gives dates for the last spring and first fall freezes (32 F or lower) at each station with sufficient minimum temperature data for calculations to be performed.
The period for which records were available is shown in the table in the second column from the right. Three spring dates are given the average date of the last spring freeze and the earliest and latest dates on which the last spring freeze has occurred during the period of record. Similar dates are given for the first fall freeze.
The table also gives values for freeze free season. Values include average length of freeze free season for each station and the shortest and longest freeze free season during the period of record.
Frost-free seasons are not necessarily suitable for growing your warm season crops. A good example is the 2002 growing season when temperatures dropped to near freezing in many locations. Even though the tomatoes and other warm season crops may not have been frozen, they were severely stunted by the cold temperatures in late May and again in late June.
In general, sometime during the first two weeks of May is suitable for setting out tender plants.