March 15th usually marks the last frost in the Tucson area and higher areas of Vail and Corona can see that date pushed back as far as May 1st, so it can be tricky to decide when to plant your spring garden.  Some people mark the last frost by the point when the mesquite trees in their area begin to green up. But don’t count on your deciduous fruit trees to tell you when Spring is really here because you could lose your crop if you do.  Our 70 and 80-degree days in February can promote fruit trees budding out and it’s hard to hold yourself back from planting all the varieties of crops that love the warm temperatures but don’t be fooled or you’ll be starting over!

After your area reaches the last frost date, that’s usually a safe bet for planting out your spring garden. Tomatoes, chilis, corn, bush beans and herbs like basil and chives go in first and a couple weeks later, add in your cucumbers, melons, eggplants, sweet potatoes, pole beans, and squash plants. You can plant either seeds or small starter plants, but note that these are the dates for starter plants so if you start from seed, it will take you longer to get to harvest. With tomatoes, you need as much of a head start as possible for the plants to produce tomatoes before it gets too hot for the flowers to set fruit so most experienced gardeners start their tomato seeds indoors around Christmas time or they purchase starter plants in February or March. Of course, with tomatoes, once it cools down again in the early fall, your plants will start producing again, often more than they did in the spring and early summer.

Once you plant out your spring garden, be ready to cover the new tender plants with sheets if a frost is forecasted that night. “Walls of water” are another way to protect young plants from extreme cold temps and they are basically a plastic, compartmentalized cone that goes around a small plant and you fill the compartments with water. Or make your own with plastic soda bottles filled with water set in a ring around your plant. This acts like a small greenhouse, giving off ambient heat around the plant as well as protection from harsh winds.

So, to determine the best time to plant out your warm weather loving plants, keep an eye on the weekly forecast and be prepared to protect your newly planted garden if need be.

For an interactive Last Frost Date Plant Map, go to and scroll over your particular area.

Spring Garden Tour Coming Up! Private backyard gardens, school gardens, and community gardens will be opened for the public where Host Gardeners will greet visitors, answer questions and share their passion for growing things. The beginning of the tour will be at the “Ace Acre” Community Garden site, right behind Ben’s Bikes and Rita Ranch Automotive (7471 S. Houghton) where each visitor will receive a garden tour guide that maps out the address of each garden that will be on display that day, as well as the story behind the garden with an accompanying picture.

To find out when the spring 2018 Garden Tour is or to add your garden to the lineup, go to our website: or visit our Facebook page: RitaGardens.

About author View all posts

Guest Author