Garden Calendar for August 2023

August looms.  And weather is the “hot” topic right now.

But really – weather and climate do change. Just a few thousand years ago what is now the desert Southwest was a cool plains area with giant woolly mammoths roaming.  There were people roaming as well – and hunting those now extinct behemoths with spears. So yes, the world weather fluctuates and the climate changes over time even without humans creating greenhouse gasses.

Lehner mammoth kill site is in Cochise County Arizona, near the banks of the San Pedro River. Photo courtesy Wikipedia.

I am writing this in central Vermont where there have been epic floods and widespread devastation. Over a 36 hour period 12 to 18 inches of rain fell on soil that was already entirely saturated by previous rainfalls. The results – massive flooding.  Homes have been flooded to the second floor, a few washed away in landslides. Automobiles have been swept downstream or destroyed by the inundation.  Businesses have lost hundreds of millions of dollars of merchandise, and there are boil water advisories for many municipalities.

Meanwhile the Southwest is experiences record heat and aridity. Five months with no rain in some places.  Here are some tips to care for your garden this August.

Avoid such irrigation devices that spray water into dry air – half the water can be lost to evaporation.

August Gardening Tasks


Yes it is hot – but you can plant heat-loving plants.  In Low and Middle Desert gardens, August is the last good chance to plant cacti, mesquite trees, new Bermudagrass lawns, palms, and even young citrus. These plants with tropical genes need ample time get their roots down into the soil during this warm time and well before first frost. There are other fruits with tropical genes that can be planted with care now, like pineapple guava, bananas, and avocado.  In Upper Elevations, consider adding fruit trees or shrubs.

More about trees and shrubs for your edible landscape in this recent post – and in my book –

Need Some Fruit Selection Help?

May I recommend my book?  The Southwest Fruit & Vegetable Guide offers not just growing guides but some of the latest varieties – including ones specifically for raised bed and container growing. Price is what you would pay on Amazon – only when you buy from me you get a signed copy!soule-books-buy

From the review:

In this updated 2nd edition of Southwest Fruit & Vegetable Gardening, you’ll find much-needed advice and practical tips on growing an edible garden, no matter which part of the southwestern US you call home.

Growing in the Southwest isn’t easy. It’s either too hot or too cold and often very dry. The region hosts a range of soils and climate conditions that can be difficult for a gardener to navigate. That’s why this region-specific garden guide is a must-have for every Southwestern gardener!

Botanist Dr. Jacqueline Soule simplifies the ins and outs of gardening in the Southwest and serves as your guide to success. Regardless of whether you’re tending an in-ground plot, a small container garden, or a series of raised beds, Southwest Fruit & Vegetable Gardening is an invaluable resource.”

Profits from the sale of this book via my book selling site go to the Arizona-based Horticulture Therapy non-profit Tierra del Sol Institute.


Fertilizer in August

In all areas you can fertilize in August.  If you are experiencing record heat, you might want to wait a bit until your plants are less heat-stressed.

Optionally fertilize lawns, palms, flowers, vegetables, and non-legume landscape plants, during August. Nut crops can get one last dose of blooming/fruiting fertilizer. Wait until Labor Day to fertilize citrus.

This tree has a nice wide tree well planted with rain lilies as a flowering ground cover. The ground covers shade the soil and reduce evaporation.


Do water nut crops, all fruits, and especially citrus trees widely – well away from the trunk. Water deeply to ensure a good crop. Avoid shallow daily watering. Nut crops especially will benefit from watering if we don’t get rain.

General Care

Sharpen mower blades. Yes, again. Dull blades hurt the grass. Nice sharp blades means your lawn that is barely surviving the heat will survive better.

Walk your fence-line or walls. Check for spots where hungry wildlife may get in. Gates are especially an issue. If you discover a snake in your yard, it is because you have mice, packrats, or other similar food the snake is tracking with its very sensitive tongue.

Have care when opening irrigation or water boxes. Such cool shady sites are ideal spots for wildlife. These are king snakes, which will hunt and eat rattlesnakes.


August is the one month when you can prune your palms without fear of the palm borers finding tasty palm hearts to eat. Since it is still a blazingly hot month, make sure the workers leave ALL green leaves, yes, even the ones pointed down, to shade the part of the trunk with the tender palm heart inside. (More on palm care – here.)  If you can, watch you palms for a while before calling the trimming crew. Insect-eating orioles often nest up in under those shady leaves, and their young may not have left the nest yet.

Male hooded oriole at a water dish in Tucson.

If oleander plants have galls, cut affected branches off at least one foot below the galls. Be sure to sterilize clippers in bleach water or rubbing alcohol between every cut. I suggest eliminating the issue entirely by removing the toxic oleander and planting the non-poisonous Arizona rosewood (Vaquellenia californica). I shared a nice discussion about this lovely low-water native plant on the Gardening With Soule Membership site.

Look for Chlorosis – Yellow Leaves

People may over-water when the rains don’t come. Look for chlorosis. Plants with paling, often yellow, leaves but with green veins are suffering from the inability to take up the iron that is rich in our desert soil. Books written for Back East call this iron-deficiency and tell you to add iron. DON’T waste your money adding iron! Our Southwest soils are alkaline and the plants are showing alkaline-induced-iron-chlorosis.


Chlorosis Treatment

Quick treatment for chlorosis in the Southwest is 1 cup vinegar in 4 gallons of water and use this mix to water plants with. Chlorosis may clear up within 2 weeks. Sadly, it will reappear as alkaline soil molecules do migrate. Plus our ground water is alkaline, so every time you water your plants, you add alkalinity back.

Long term treatment of chlorosis is to add compost to the soil and add coffee grounds or other soil acidifiers on a regular basis. Susceptible plants include roses, plus non-native fruit trees like citrus and apples. I wrote more on citrus care -here.

Tasks After mid-August


In Low and Middle Desert, you can plant a fall vegetable garden with pumpkins, squash, zucchini, bush beans, and robust seedlings of the deadly nightshades (if you can eat them): tomato, pepper, tomatillo, and eggplant. Also cut back any over-summered tomato plants. This will encourage new growth and fruit in fall.

In Upper Elevations plant the cool season fall vegetables like radishes, lettuce, and kale.

But Wait – There’s More!

Yes, there are many more garden tasks that you could do in August, more vegetables to plant, etc.  Entire books worth. 😉  These are just some of the top things to consider.



© Article copyright Jacqueline A. Soule. All rights reserved. You must ask permission to republish an entire blog post or article. Okay to use a short excerpt – but you must give proper credit to Gardening With Soule. You must include a link to the original post on my site. No stealing photos.

Be the first to reply

Leave a Reply

Your email address will not be published. Required fields are marked *