Warm Season Veggies

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By definition, warm season vegetables are the ones that really can’t stand the cold – things like tomatoes and eggplants and melons. Because they are so susceptible to cool temperatures, they are typically planted outdoors only after the last frost of the spring.

Which is a problem here in northern Arizona. By the time we have the last frost of spring, it’s practically summer, which can make things challenging, but not impossible. With a few modifications, you can harvest homegrown goodness even when the weather is a little unpredictable.

Here are a few pointers to being a veggie champion at 7000 feet.

Understand your microclimate

Depending on your neighborhood, the greater Flagstaff area ranks anywhere from a “5” to a “6a” in the USDA hardiness zone, and a couple of miles can make a huge difference here. The base of Mount Elden, part of an “inversion zone” where the air temperatures above ground are warmer, is likely to get several more weeks of optimal growing time than a garden located in Fort Valley or Baderville.

Which means if you only have 80 frost-free days, you might want to avoid that squash that needs 100 days to mature. Warner’s Nursery has planting guides that can help you understand your area and which veggies will do best in your garden, but in general, you should look for seeds that only require a short growing season or are “cold hardy.”

Plant properly

Whether you are starting from seed or using transplants, there are a few guidelines that will promote veggie success. For seeds, mark out straight rows for easier cultivation and follow the directions for seed spacing on the package. Make sure they are planted at the proper depth (for example, lettuce and carrots only need ½ inch of soil coverage, while beans and peas require up to 2 inches).

Transplants need tenderness as they move from their pots or flats into your garden. Don’t let them dry out before you get them in the ground, and water thoroughly before taking them out of their containers. Be careful with the roots and disturb them as little as possible (although if the roots are all bundled up or “pot bound” you might want to tease them out a bit). Dig a hole large enough so the plant sits slightly deeper than it was in the container, and cover with soil, making sure there are no air pockets. You might want to use a starter solution and we can help you with the best selection for your plants.

Water well

Irrigate to keep your soil moist and be consistent about it. Excessive fluctuations in soil moisture can adversely affect the growth and quality of your vegetables. Frequency of watering will depend on several factors: Is your vegetable shallow- or deep-rooted? Is it a large or small plant? And of course, what’s the weather been like? If we’re in monsoon season, the need to water is less urgent. 

Prepare to protect your plants

Hard as it might be to believe, your sweet tomatoes, cute carrots and beaming Brussel sprouts have enemies – unpredictable frosts, bullying weeds, pests and diseases.

Your biggest ally in this is various season extenders. The most popular ones are tubes of water that go around the plant. They absorb heat during the day and keep your plant toasty at night. Additionally, they warm up the soil under your plant, promoting good root growth and lessening the chance of shock, which will make your plant stronger.

At Warner’s, our experts can provide you with more information on season extenders and other plant protections, such as frost blankets, plant treatments or weed suppressants to shield your veggies.


All this work leads up to the biggest reward of your veggie garden: the harvest. In my humble opinion, no purchase from the produce section can match your homegrown vegetable garden – the taste, the smell, the knowledge that your veggies are free from harmful chemicals, and the satisfaction of a job well done.

Happy Gardening!