The challenge with vegetable gardening in the low desert of Arizona comes when temperatures soar in the hot, dry summer months. The low desert includes elevations below 3500 ft in the Southwest, such as the Phoenix and Tucson metro areas.
It is possible to have a productive vegetable garden in hot climates like Arizona during the summer heat. Here are the essentials to know for summer gardening in Arizona and other hot climates.
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6 Tips for Summer Gardening in Arizona
1. Plant Heat-Loving Varieties for a Summer Vegetable Garden in the Low Desert of Arizona
When summer vegetable gardening in Arizona, choosing suitable vegetables and planting them at the correct time is a matter of life and death for the plants.
Use this Arizona Vegetable Planting Guide. Select varieties that mature quickly.
A few vegetables survive and even thrive in our intense summers. Here are a few of my favorites:
Looking for a summer spinach alternative? Try Malabar spinach, a heat-loving veggie that is not a true spinach, but rather an Asian vine that is high in vitamins A and C. Plant from March through May in the low desert, and harvest it all summer and fall. For more information about growing Malabar spinach, read this post.
Sweet Potatoes grow best in hot weather. Plant transplants or slips from the end of March through June in the low desert of Arizona, and the leaves will keep your garden green and beautiful all summer. Harvest sweet potatoes in late fall. For more information about growing sweet potatoes, read this post.
2. Provide Shade for Summer Vegetable Gardens in Arizona
The sun’s intense rays in the hottest months of the year are too much for most plants. Shade cloth, sunflowers, and vining plants can all be used to provide shade for tomatoes, bell peppers, newly-planted plants, and other plants that prefer shade when summer gardening in Arizona.
Shade Cloth for Summer Gardening in Arizona
If you are growing a vegetable garden during the summer in Arizona and the garden area is in full sun, consider adding shade cloth. Don’t think of completely enclosing the garden, but rather providing some relief when the sun is at its highest. The area should receive some sun throughout the day. For example, attach shade cloth to existing trellises with zip ties.
Sunflowers Can Shade Arizona Summer Gardens
Vining Plants Can Shade Arizona Summer Gardens
When growing a vegetable garden during the summer in Arizona, consider planting sun-loving vining vegetables (Armenian cucumbers, luffa, malabar spinach, etc.) purposely to provide shade for other plants that don’t tolerate full sun. Notice areas in your garden that could utilize plants as shade. For example, vining vegetables can be grown over artichoke crowns that go dormant during hot summers to protect them from intense heat that might damage the crowns.
Want more ideas for creating shade in your summer garden? This article shares more of my favorite tips.
3. Water Arizona Summer Gardens Correctly
Watering summer vegetable gardens in Arizona correctly is the most critical care you can give your plants. Problems in the garden are often traced back to watering issues.
Observing your plants and soil is the best way to determine how much you should water. There is no set time for everyone to water because many factors are involved (sun, shade, air temp, microclimate, age and size of the plant, etc.).
Principles to consider when watering:
Water deep and wide enough to moisten the plant’s root system. Use a soil probe to check the watering depth. If the probe moves easily through the soil, it is moist. If not, the soil is dry. Or check with a moisture meter. Let the top inch of soil dry out before you water again.
Monitor plants for signs of underwatering stress (leaf curl, wilted or dropped leaves, branch dieback) to help you determine how often to water. Plants require more water in dry, windy, and summer heat.
Do not overwater. Plants that wilt in the afternoon but recover by morning suffer heat stress, not water stress. Take care to add more moisture so as not to cause root rot. Check the soil for moisture before watering. Allow plants to develop some heat tolerance by not overwatering.
Water deep and wide enough to moisten the plant’s root system and prevent salt burn. Salt builds up in the soil where the watering level ends. It is good to occasionally water deeply to flush the salts out of the root zone and ground.
Water the soil not the plant. Avoid putting water on the leaves because of the salt content in our water. Wet leaves can also encourage and spread disease. Drip systems are effective for this. I use the watering grids from Garden in Minutes Use code Angela10 to save $10 off $100.
Water in the morning. Plants absorb moisture more effectively in the morning. It prepares plants before the heat of the day. Morning waterings also help prevent waterborne diseases and pests if you water at night.
Some type of automatic watering system is best. Automatic watering can be simple, such as a battery-operated timer connected to your hose bib, with either a soaker hose or drip line going to the garden. Try to be in the garden when the system is on so you can be aware of any issues (leaks, dead battery in the timer, etc.).
Consider adding ollas to the garden for extra thirsty plants (tomatoes, squash, etc.) rather than running your irrigation system extra time or watering by hand (which can get water on leaves). Ollas are a form of plant irrigation that provides water slowly at the roots as the water seeps out the terra cotta pot that is buried underground. You refill the olla as it empties.
4. Mulch Summer Gardens in Arizona
Mulch, mulch, and mulch your vegetable garden during Arizona summers. Use compost, pine needles, or straw around your plants. Growing a vegetable garden during the summer in Arizona means adding mulch.
Here are a few of the many reasons to mulch:
- Insulates the soil and keeps the temperatures even.
- Mulching slows evaporation, allowing plants access to more water.
- Mulching keeps the soil from developing a hard crust that is difficult for irrigation to soak into.
- Weeds are less likely to sprout. When you mulch, your plants won’t compete with weeds for water and nutrients.
- As the mulch decomposes, it adds organic matter and nutrients to the soil.
5. Adjust Expectations for Summer Gardening in Arizona
- Understand your garden will probably not look its best in the summer heat.
- Be aware that pollen in pepper and tomato plants may not be viable when temperatures are over 100°F. The set fruit will continue to mature, but new fruit may not be produced.
- With intense heat, long days, and nights that don’t cool off, many plants go into summer dormancy. They focus on staying alive rather than growing.
- This is not the time to prune, trim, or over-fertilize.
- Stressed plants are more prone to pests and diseases. Monitor plants and consider pulling them if they become overwhelmed so the rest of the garden is not infected.
- During the monsoon season and more humid months of July and August, plants may emerge from dormancy.
6. Consider Taking the Summer Off When Gardening in Arizona
Growing a vegetable garden during the summer in Arizona is challenging. If you travel frequently, don’t like the planting options, or would rather not spend extra time outdoors during the hottest time of the year, here are some alternatives:
- Let the garden rest. Cover with a very thick (3-5 inch) layer of mulch and provide some irrigation. Do not let the soil dry out.
- Feed the soil with a cover crop. Learn more in this article.
- “Solarize” your soil. Only do this if your soil has significant weed issues, diseases, or nematodes. Solarizing the soil uses the sun’s heat to kill the weed seeds, diseases, or nematodes lurking in the soil. Unfortunately, it also kills the beneficial microbes in the soil.
A Basic Overview of Solarizing:
- Add manure into the soil & water well.
- Cover with clear heavy plastic sheeting.
- Bury the edges of the plastic, or hold it down with rocks.
- Allow soil to “bake” in the sun for 6 weeks.
- For more information about solarizing soil, read this article from the Arizona Cooperative Extension office.