Watering Your Garden During the Summer’s Heat
ORIGINALLY FROM MAY 2021, UPDATED SEPTEMBER 2026
California is the driest of the Mediterranean climates. The state relies on ample winter snow pack in the Sierras to provide water to our watersheds throughout the spring and summer months. I recently learned that 40% of California's water comes from the snow pack! So when there is not enough snow, we suffer a very dry year ahead.
Sadly, this water deficit is directly related to our rapidly changing climate. The lack of water has massive impacts beyond what we can see. As extreme drought becomes the norm in California, we need to learn ways to get the most out of every drop of precious water. So what can you do to protect your garden, making it resilient during the summer’s hot, dry season?
Know Your Watering Habits
Smart watering starts with the foundation. Before you jump into learning about proper watering techniques, I suggest that you look at how you are already watering your plants. Here are some questions to ask to assess your current watering habits in the garden:
Do you water with a drip irrigation system that you schedule from a controller? This is the most efficient way to water because you can direct the water specifically to target the root zone and water thoroughly. Just remember, this is not a set it and forget it system. The watering schedule will change according to the plant's needs.
Do you water with the irrigation system pop-up sprinklers that spray water over the garden? Pop-ups lose a lot of water due to wind and evaporation. Plus, they can over-spray and waste water. Look to see if your municipality has an irrigation conversion rebate to switch out pop-up for drip.
Do you hand water? This can be very efficient. However, be sure to water the roots, avoiding the crown and the leaves since this can cause disease.
Do you recycle water? A rain catchment system is a great way to water your garden with free water. You can also fill a bucket with water from a sink indoors as you are waiting for the temperature to reach “hot” and then use that captured water in the garden. My favorite way to water my trees and shrubs is with a laundry-to-landscape greywater system. Every little bit helps and plants love recycled water.
3 Watering Tips For the Summer Heat
August and September are the driest and often the hottest months of the year in California. Though we are on the other side of the summer solstice, with shortening daylight hours, we are also the furthest away from our rainy season. Summer here is basically a masterclass in how to keep a garden happy while the sun tries to steal all your moisture. The good news? There are a few tried-and-true tips I can share with you to help your plants thrive during the summer while saving water.
1. Know when to water
First things first: water deeply, not just “a little.” Aim to soak the root zone, which is the outer edges of the plant, not at the crown (where the base of the plant meets the soil). When you do, the roots grow downward instead of staying near the surface. A soil check will let you know, simply push your finger (or a small trowel) into the soil about 2-3 inches. If it feels dry, it’s watering time.
Just because the leaves are wilting doesn’t mean the plant needs water. Check your soil first! A heat stressed plant may be well watered and still look wilted during the heat of the day.
Lastly, the best time of the day to water is in the early morning between 5-8 AM when the soil and air is still cool. Avoid watering during the heat of the day when you can, as this will be less effective.
2. Add mulch to conserve water
When it comes to watering your garden, you want the water to infiltrate into the soil, not run off of it. You achieve this by adding organic matter (compost) to the soil, then protecting the soil with a nice layer of mulch to prevent it from becoming hydrophobic. I recommend wood chips! Avoid rocks, crushed shells, and non-organic materials like rubber chips as they hold too much heat (among other unfavorable reasons). You also want the water to stay in the soil. A layer of wood chips over the soil reduces the water evaporation rate significantly. Finally, make sure to add compost and water deeply.
PRO TIP: Always follow CAL-FIRE’s recommendations of avoiding wood mulches within the first 5’ or structures to prevent fire hazards.
3. Water efficiently and thoroughly
Whichever way you irrigate your plants, you'll need to make sure you are getting that water deep. We want to grow deep root systems and we do this by watering deeply. Your goal is to get that water down 5-12 inches depending on the plant. For my perennials and veggies, I am shooting for a good 5-7 inches. Then we wait until the top few inches of the soil is dry before we water again. This may take a number of days. For larger shrubs and trees, I go deeper and water even less often, perhaps providing a deep soak only once a month or so.
Now, when you lay out a nice thick layer of mulch – like the wood chips I recommend – you reduce that water evaporation tremendously. The top will look dry due to sun exposure and wind, but when you feel down a couple of inches, the soil will be nice and moist.
The major benefit of this approach to watering your garden is that, in times of extreme heat and drought stress, your plants are happy as can be because they have water to access around their deeper root zone. When you water shallowly, that water evaporates quickly and requires more frequent watering. When this goes unnoticed over time, your plants become stressed. Drought-stressed plants become weak and are prone to pests and diseases.
How Often Should You Water in the Summer?
As a professional in the garden industry for 25+ years, I’ve found that no one can tell you how much or how little to water your plants. Only you know. Why? Because it depends on:
Your soil texture and structure
The plant material
Your plants’ water needs
Whether there’s a nice layer of mulch protecting the soil
How the sun moves across your garden
If there are heat pockets in your garden
Environmental conditions (i.e., is there a wind tunnel that whips through in the afternoons?)
The layout of your garden (i.e., is your garden primarily potted plants on a concrete patio?)
There is so much to take into consideration. This is why it’s important for you to learn how much you watered effectively. After you feel that you have provided enough water to that area, double check how well it actually permeated the soil. There are many times when I thought I watered really well and I was shocked to see that my watering efforts only reached ½ an inch down. I invite you to get curious and see how well the water is getting down into the soil.
Before you water again, feel the soil down a few inches. Has it dried out yet? The surface will always look dry, which is why I recommend you dig down a bit to check. Once the soil has dried out, then it's time to water again. Even if a plant looks wilted, feel the soil. Plants can wilt when they are overwatered or if they’re too hot. Strange but true!
So, how do you know if you’re watering enough? You have to check the soil. Feel the soil with your fingers, dig down a bit with a trowel, or use a moisture meter. Choose any tool that will help – you just need to know.
Ways to Grow Together
As we face another year of hot, dry conditions, I hope these tips for how to water more effectively and efficiently help you protect your plants while saving water. Proper watering techniques and timing is crucial to create resilient plants and gardens when water is scarce. Droughts and heat waves are here to stay, so be smart and learn how to garden through them. Stay cool and have fun in your garden!