When Can I Plant Tomatoes (and other tender vegetables) In Utah?

On the Wasatch Front, anytime after Mother's Day it is usually safe to plant tender vegetable plants.  However, it's a good idea to watch the weather forcasts and make sure that nighttime temperatures aren't expected to go lower than the low 30's F.   Here is a post I wrote about frost dates.  Also, if you purchase plants that have become accustomed to the luxurious and constant-temperatured lifestyle of a nursery greenhouse, they will need to be "hardened off".  This is a process of placing seedlings outside during the day and moving them inside during the night.  They toughen up with the exposure to the outside air.  Then they won't be so shocked when transplanted into the garden.  Here is an article about hardening off plants.

seedlings almost ready for May planting!