How Much to Water Your Plants During Heatwaves - Backyard Boss
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How Much to Water Your Plants During Heatwaves

If you’ve experienced heatwaves this summer, then you know how challenging it can be to keep your plants hydrated. Soil can dry out quickly, especially when in combination with a period of drought. The watering routine you established throughout the spring and early summer may need adjusting.

It can be hard to know exactly how much to water your plants at the best of times, let alone during a heatwave. To grow healthy plants there’s a balancing act to avoid both underwatering and overwatering. Learn how much to water your plants during heatwaves to ensure you don’t make a watering mistake.

What’s a Heatwave?

waterdrop water the plants plug
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When daytime temperatures exceed 90 degrees and nighttime temperatures remain above 70 degrees Fahrenheit, this is a heatwave in many regions. Depending on the area, it may be dry or humid. During these periods of extreme heat, you will need to water more often.

How Often to Water 

a person watering plants with an aluminum watering can
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During heatwaves, your weekly watering routine will likely need to increase to at least two to three times a week. Keep an eye on the forecast and be sure to plan your watering days accordingly. Check the soil regularly and water when the top inch of soil is dry.

To test this, insert a stick into the soil for a few minutes, you can also use your finger. When you remove the stick, feel the bottom for moisture. If its dry, then its time to give your plants a healthy watering.

Watering Daily

Some plants, especially those in pots and hanging baskets, may require daily or twice-daily watering during extreme heatwaves. An easy way to check potted plants is by lifting them to test their weight. If they feel light, then they likely need water.

Tomatoes are a popular container plant that drinks a lot. If you find you have to water twice a day during heatwaves for this crop, you may want to look at your other vegetables to make sure they aren’t struggling. Other aiding factors in a heatwave include mulching, or moving potted plants to a shadier location.

How Much to Water 

person watering the plants
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Knowing how much to water your plants at a time is important. Depending on the climate, soil type, mulch or cover provided, and types of plants you are growing, the watering needs can vary. During heatwaves, it may be tempting to drench everything, but overwatering is still possible. Remember to test your soil before drowning your plants in a heatwave.

How To Measure 

Plants need about one inch of water per week, but how do you measure that? For a four by eight raised bed, one inch per week equals approximately 20 gallons of water. During a heatwave, you will need to give this size of bed three gallons a day or six gallons of water every other day. If you water with a hose, you can fill up a three or six-gallon pail and time how long it takes. This will give you an idea of how long to water that bed for.

Use a Rain Gauge

rain gauge measurement
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One of the best ways to see how much water outdoor plants are already getting is by using a rain gauge. These can also measure how much water your sprinkler system provides. Unfortunately, rain gauges aren’t as helpful during periods of drought or for measuring how much you’re watering by hand. But, during a heatwave, they can be a prized possession. 

Water Indoor Plants More

green leafed plants in pots
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Much of the focus is on outdoor plants, but indoor plants also require extra water during heatwaves. The intense sun that hits your outdoor plants, although not as bright inside, will increase in intensity inside during hot spells. Plants that are closest to windows will feel the effects of the sun the most and you may notice the soil drying out faster than normal. Having central air or open windows will also determine how often you need to water.

Houseplants that are not drought tolerant may need water a few times a week, or whenever the top inch of soil is dry. Five to seven-inch containers require approximately one cup of water.

How to Water Your Plants During Heatwaves

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Water your plants slowly and evenly. If you do it too fast, the water can run off before the roots are able to absorb the water. When watering pots or hanging baskets, use a combination of top and bottom watering to ensure the entire soil medium is wet.

Water deeply, but don’t flood your plants. Deep watering is especially important for trees that have deep root systems. Water your garden beds down to a depth of 15 inches, using a stick to measure how far down the water is reaching.

Watering cans work well for measuring purposes but are time-consuming for large gardens. If you are using a sprinkler system, it’s best to use ones that spray low to the ground to reduce water evaporation. This can work well for lawns and low gardens, but for high-growing gardens, this approach may not work.

Listen to Your Plants

Plants often show signs of underwatering, such as wilting, when in fact they are just protecting themselves from the heat. Listen to your plants and watch for signs of stress. If wilted plants aren’t rebounding at the end of the day, then they may need more water. Adjust your watering routine during heatwaves accordingly.

To conserve water, consider collecting rainwater. You may also want to explore other ways to protect your plants. If you have any plants that have already suffered from heat damage, here are some ways you can help revive them.

So, how much do you water your plants during heatwaves? If this article helped you, feel free to share it with others!