Monsoon Gardening in Arizona: How to Garden During Monsoon Season

If you garden in the low desert of Arizona, you may have heard other gardeners talking about “monsoon gardening.” Does that mean when the nightly dust storms and lightning begin, it’s time to head outside and get digging? Not exactly, but those storms are a signal that it may be time to plant a second round of heat-loving crops. Monsoon planting has existed for centuries, and in this blog post, you will learn how, when, and what to plant during monsoon gardening in Arizona.

1. What is a monsoon?

The official definition of ‘monsoon’ is “a persistent surface wind flow pattern caused by differential heating that shifts direction from one season to another” (Greer 1996). This shift in weather patterns transports moisture (primarily) from the tropical Pacific Ocean up through western Mexico, and is the beginning of the summer monsoon season. 

“The North American Monsoon System (NAMS) is an important circulation feature for Arizona due to its control of summer precipitation amounts across the state. Thunderstorm activity during the summer monsoon season can contribute to over half the annual precipitation over Arizona’s southeastern and higher elevation areas.” (Bryson and Lowry 1955, Hales 1974, Carleton 1986, Douglas et al. 1993, Adams and Comrie 1997).

The low desert of Arizona is on the northern border of the North American Monsoon System. Our monsoon activity (wind, thunderstorms, dust storms, rain) varies significantly from year to year. Complex factors influencing the monsoon can shift our weather from monsoon-like to hot and dry. To learn more, read Arizona and the North American Monsoon System. 

What does all of that mean? In simpler terms, our winds shift, and we have winds that come in from the South through the summer and bring moisture into Arizona. The added moisture is what creates our summer thunderstorms.

Due to the monsoon, from June through September, wind, rain, dust, lightning, thunderstorms, and even hail are possible in Arizona. However, each year is different, so there are no guarantees for extra moisture. 

2. What is monsoon gardening?

For centuries, the residents of Arizona and the northwest areas of Mexico have been growing with the monsoons. It has long been considered a second planting window for heat-loving varieties, such as amaranth, beans, tepary beans, corn, and squash. 

3. What differences can I expect during monsoon season?

As the monsoons arrive, there is a literal change in the air, so to speak. Although there is wide variability from year to year, here are some differences you may see: 

• Higher humidity
• Wind and possible microbursts
• Dust storms
• Rain
• Additional insects and pests:
  • Palo verde beetles
  • Leaf-footed bugs
  • Cicadas
  • Cicada killer wasps

4. How do I prepare for monsoon season in Arizona?

Although you don’t know how severe a particular year’s monsoon season will be, preparing for the possible moisture and additional wind is vital.

Monsoon rains are often intense but short-lived, so being ready to capture that water makes a big difference. Adding a rainwater harvesting system was on my gardening wish list for years, and now that I have one, I see every storm as an opportunity. Before the rains arrive, take a little time to set your yard up to keep that water where it can benefit your garden. I explain how in my guide to harvesting rainwater in the desert.

Prepare your trees, garden plants, and any structures in the garden for the monsoon season by anticipating the increased wind. 

To prevent damage to trees: 

• Trim desert trees during May. Open the canopy up to make them more wind-resistant.
• Thin an abundance of new growth on deciduous fruit trees so the wind can blow through them.
• Water trees deeply to encourage a robust and deep root system. 
• Remove trees weakened by pest or disease issues. 

Prevent wind damage to garden plants by staking tall plants (corn, sunflowers, zinnias, etc.). Tie plants to supports loosely to allow for movement, but prevent the crop from breaking off or falling.

I use bamboo stakes and these plant clips to support tall plants. I also plan ahead by planting giant sunflowers next to one of the many vertical supports I already have in place in my garden. Then I can tie the stem to the existing support. 

When using any kind of support, it is essential to check it throughout the season to ensure it is not girdling the stem of the plant.

A garden’s vertical supports and shade structures need to be strong enough to withstand the extra wind during the monsoon season. The steel poles for my large shade structure and arched trellises are all buried 2 feet deep and cemented in place. The supports and shade structures in your garden should be made in such a way to allow air to pass through. 

5. What can I plant during monsoon season?

Warm-season crops that grow well during monsoon season include:

Plant from transplants: Basil, Tomatoes, Tomatillos, Peppers, and Eggplant.  

Plant from seeds: Amaranth, Corn, Cucumber, Basil, Okra, Squash, Winter Squash (including pumpkin), and all the beans: Tepary Beans, Pinto Beans, Lima Beans, Pole Beans, Bush Beans.

If you have a choice, select shorter “days to harvest” varieties. The summer solstice has passed, and the days are getting shorter. As a result, plants will take longer to ripen.  

Plan your garden with this detailed Arizona Vegetable Planting Calendar for the Low Desert, to help you grow successfully in desert conditions.

6. When is the best time to plant during monsoon season in Arizona?

Although monsoon conditions may be present, temperatures are often scorching. Here are a few tips for determining when to begin planting: 

• Planting conditions may be right anytime from mid-July through the end of August. Each year is different, and there are no guarantees.
• Look at the weather – if it’s 110°+, I’ll wait – nothing likes it that hot. Look at the forecast and if there is a dip for several days in the temperatures expected, choose that time to plant. 
• Take the necessary time to harden off transplants before planting. Done right, it can take up to two weeks. 
• Plant transplants in the evening to give transplants overnight to settle in.
• Baby new plantings for the first couple of weeks. Provide additional shade/water as needed.
• Plant seeds a little deeper; the soil is cooler. Mulch newly-planted seeds lightly to help preserve moisture. You may need to water newly-planted seeds a couple of times daily. 

7. How do I water during the monsoon gardening season in Arizona?

• How often you water depends on several factors including your soil and current weather conditions. You will need to water more often in hot, dry, windy weather. Hot weather with high humidity usually means you can water less often.
• Use a soil probe or moisture meter to check soil moisture levels before watering. Too much water will rob them of oxygen and rot the roots. Increased humidity may lower water needs.
• If water is needed, water your garden in the morning to ensure the plants are well-hydrated for the day ahead. 
• When there is a dust storm, spray plants off to discourage spider mites and remove the dust. Spray off foliage in the morning so the leaves dry quickly.
• Use a rain gauge. It is difficult to tell how much moisture was received during a storm. If you receive more than .2 inches, skip a garden watering. If there was at least ½ inch of rain, skip a landscape watering. 
• Water landscape plants twice as long at least once during the summer to push the accumulated salts down through the soil and away from the roots. (A long, deep, soaking rain may do this for you.)
• Watering fruit trees regularly during the summer helps prevent problems like splitting fruit in oranges and pomegranates later in the season.

8. Do I still need to provide shade during monsoon season in Arizona?

If you have shade in place, keep the shade up until temps are consistently below 100°F. Be aware that storms may damage it. There’s little you can do if a microburst comes through, but have shade be sturdy to withstand strong winds. To learn more about adding shade to your garden, read this post.

9. How do I manage pests and diseases during monsoon season?

Daily observation is crucial to managing pests and diseases when monsoon gardening in Arizona. During monsoon season, conditions are magnified, and the added heat and humidity mean pest damage and diseases can happen rapidly. 

Spending time in your garden, even though it is hot, is the best way to stay on top of issues. Handpick insects and discard damaged leaves. If things get out of hand, don’t be afraid to dispose of infected plants rather than having them infect the rest of your garden.

Continue to follow good cultural-management practices: healthy soil, crop rotation, understanding crops’ preferred growing temperatures, watering correctly, choosing disease-resistant varieties, plant spacing for adequate airflow, keeping the garden clean, not letting weeds get out of control, attracting beneficial insects, etc. 

• Spider Mites – spray down the garden after dust storms and occasionally when it is very hot and dry. Learn how to get rid of spider mites here.
• Squash Bugs – row covers; handpick and destroy eggs, nymphs, and adults; crop rotation; vertical gardening; boards under plants as traps; plant resistant cultivars (butternut, early summer crookneck). Learn how to get rid of squash bugs here.
• Thrips – spray down with water; rolled cardboard traps; blue sticky traps (use for a limited amount of time and frequently change until the problem is under control). Learn how to get rid of thrips here.
• Grasshoppers – attract birds; floating row cover.
• Leaf-footed bugs – handpick and destroy eggs, nymphs, and adults. Learn how to get rid of leaf-footed bugs here.
• Ants – are usually beneficial and not problematic; if they are causing severe damage, use ant bait traps. 

For more information about organic pest control, read this article.

10. Anything else I can do during the monsoons?

In addition to (or instead of) planting monsoon crops, there are other garden tasks to do during monsoon season in Arizona: 

• Mid-August or early September, cut back existing tomatoes, peppers, and eggplants to encourage new growth. 
• Plant a cover crop (warm-season cover crops include buckwheat, cowpeas, sweet potatoes, and tithonia) if you aren’t going to plant for 6-8 weeks. 
• Make a plan for your fall and winter garden. Start seeds indoors for cool-season crops.

In this article, learn more about using cover crops during summer to improve garden soil.

For more garden tasks to do each month, see my monthly guides.