It’s a steamy 90°F summer day. You look out at your lawn and notice faded, yellowy patches starting to appear in the grass. Time to break out the hose and give that thirsty turf a good soaking, right? But then a nagging thought crosses your mind – isn’t watering grass in direct sunlight a bad idea? You’ve probably heard it can burn or damage the blades. So what’s the real deal here – #does watering grass in the sun burn it or not?
Let’s dig into the details and uncover the truth about watering grass on hot sunny days.
Timing Is Everything: When’s The Best Time To Quench Your Lawn?
Watering grass isn’t as simple as just turning on the sprinkler anytime your lawn looks thirsty. To keep your turf green and healthy through the dog days of summer, you need to be strategic about when you irrigate.
The ideal time to water grass is early in the morning, before 10 AM. Watering in the early morning allows the liquid refreshment to soak deep into the soil and penetrate down to the grass roots. The low angle of the morning sun and cooler temperatures reduce evaporation, so more water is absorbed by the lawn instead of wasted. Early morning irrigation sets your grass up to withstand the heat of the day ahead.
Late afternoon or early evening is another favourable time for watering your lawn. After 4 PM or so, temperatures start dropping as the sun gets lower in the sky, and evaporation slows down. Watering in the late afternoon or early evening enables your grass to take up moisture through its roots while still active and growing. Just be sure to complete any evening watering a few hours before sundown to allow time for drying.
When it comes to the best time of day for watering grass, night time irrigation really can’t be beat. As temperatures drop after dark, giving your lawn a deep drink is the optimal time. Minimal evaporation means the water soaks down into the soil profile. And since grass growth happens primarily at night, an evening irrigation allows the turf to utilize that moisture right away. For many homeowners, setting their sprinklers to run overnight is the most convenient approach.
Now for when you want to avoid watering your lawn – right around midday when the sun is directly overhead. Irrigating grass in the peak heat of day is wasted effort. Intense evaporation prevents water from ever reaching the roots before it vaporizes off the grass blades. Midday watering can literally do more harm than good, as it stresses the already heat-fatigued grass.
Beware The Scorching Summer Sun
Why exactly does the sun cause issues for lush, green grass? Understanding how sunlight impacts turf health gives you insight into proper lawn care.
Intense heat and sunlight cause the blades of grass to shut down and stop active growth. The stomata on the grass leaves close up as a survival mechanism in the heat, which limits its ability to take up water and nutrients. This defences response is more pronounced in cool climate turfgrasses.
Prolonged exposure to high temperatures above 90°F can damage the tender new shoot growth at the crown of the grass plants. Extended hot and dry periods lead to drought stress, which causes grass to turn yellowish, brown, or die back in unsightly patches.
Mowing your lawn too short leaves the crowns and roots more exposed to the drying effects of the sun. Taller grass blades provide crucial shading that helps retain soil moisture. Proper mowing height varies by turf type, but a range of 3-4 inches is ideal for most northern grasses during summer.
The takeaway? Adequate soil moisture is critical for keeping your grass happily growing despite Mother Nature’s heat waves. Time those lawn sprinklers wisely!
Does a Little H2O Really Fry Grass in the Hot Sun?
This brings us back to the original question – will watering your lawn in direct sun actually burn the grass? The notion that wet grass blades magnify the sun’s rays, scorching the tender leaves, is intuitive. But science says otherwise.
Research shows water droplets are too small to concentrate and intensify the sun’s radiation enough to burn the grass. However, there is some truth to the concern. Watering when the sun’s beams are most intense means much of that liquid refreshment is wasted to evaporation before it ever reaches the thirsty roots.
You can check this yourself – try spritzing water on your arm on a hot sunny day. Though it may feel momentarily cool, your skin doesn’t get burnt! The key is getting moisture down into the soil, where grass roots can access it.
If you notice burnt, yellowed patches in your lawn, the real culprits are likely:
- Salt build-up from fertilizers or minerals in water
- Over-fertilization burning tender roots and crowns
- Pollutants like pet urine scorching the grass
- Overwatering leading to fungal diseases
- Thatch build-up preventing air and water from penetrating
The notion that watering grass at night causes fungus or disease problems is also largely a myth. The exception would be high-maintenance golf course turf that is mowed extremely short. For most lawns, irrigating at night is ideal.
Newly laid sod that is freshly taking root requires diligent watering when first installed, which may mean daily irrigation even in hot sun. But established lawns have deeper roots that access moisture below the surface.
Quench Your Turf’s Thirst The Right Way
Figuring out the proper watering frequency and depth for your lawn can take some trial and error. Let’s look at some general guidelines.
Most lawns need about 1-1.5 inches of water per week for healthy growth. This should come from a combination of irrigation and rainfall. During the heat of summer, plan to water your grass 2-3 times per week if Mother Nature doesn’t help out.
For light watering, allow 15 minutes of sprinkler time over the lawn area. For a more thorough soaking to replenish deeper soil moisture, water for 20 to 30 minutes. The goal is to wet the top 6-8 inches of soil without runoff. Installing an in-ground sprinkler system on an automatic timer makes lawn irrigation effortless.
Use a rain gauge or straight-sided tin can to measure sprinkler output and ensure you are achieving adequate watering depth. If 1 inch of rain falls, skip irrigation for the week. Observe how quickly your lawn dries out between watering to guide your schedule.
Turfgrass species adapted to cool northern climates have shallower root systems and need more frequent summer watering to stay green. Examples include fine fescues, Kentucky bluegrass, and perennial ryegrass. Warm season southern grasses better tolerate drought, including Bermuda, zoysia, and centipede.
When temperatures peak, you can allow highly drought-resistant grasses to go summer dormant. Their top growth browns but the crowns and roots remain alive, greening up when cooler weather returns. Just water deeply once every 2-3 weeks to keep crowns hydrated.
Maximize Sprinkler Success: Pro Tips For Watering Grass
What other wisdom can help you master lawn irrigation? Follow these best practices and you’ll have lush, enviable grass despite heat waves.
- Adjust watering frequency and amount based on weather, grass species, and soil type. Sandy soil needs more frequent watering.
- Prioritize early morning and late afternoon times to reduce evaporation.
- Use an automatic sprinkler timer to target ideal watering times.
- Avoid peak sun hours between 10 AM to 4 PM.
- Check soil moisture before the next scheduled watering.
- Aerate compacted soil to improve water absorption.
- Mow high, around 3-4 inches, to promote deeper roots.
- Water more deeply but less often to train grass roots to grow downwards.
- Allow periods of dormancy during extreme heat rather than overwatering.
- Monitor for signs of underwatering vs overwatering.
- Fertilize conservatively and organically during summer.
- Overseed thin areas in fall so grass fills in by next year.
For Great Grass, Focus Below The Surface
The key to lush grass that withstands heat, drought, foot traffic, and other stresses lies hidden below the soil. Maximizing the health of your living soil and grass roots ensures your lawn thrives.
Incorporate fine compost into the top layer of soil or top dress lawns with high-quality compost blends. This adds organic matter that retains moisture and nutrients. Test soil pH periodically and adjust as needed to match your grass species’ preferred range.
If thatch – the spongy undecomposed organic layer – exceeds 1/2 inch depth, dethatching followed by core aeration is advised. Thatch prevents air, water, and fertilizer from reaching the soil. Dethatch in early fall, aerate a week later, then overseed bare areas.
Minimize foot traffic and lawn equipment use during summer’s heat to reduce soil compaction. Leave short clippings on the lawn to break down and recycle their free fertilizer back to the turf. Overseed thin spots in fall so grass fills in fully by the following year.
Before winter, have your irrigation system professionally winterized. Insulate any above-ground pipes and backflow preventers.
Keep Your Grass Green, Not Scorched
The notion that watering lawn grass under the blazing noonday sun will fry or burn the blades is not entirely accurate. But there are good reasons to avoid irrigation during peak sunlight hours. Prioritizing early morning and late afternoon watering sessions maximizes the moisture your turf can absorb while minimizing waste from evaporation.
The real keys to healthy grass that withstands heat and drought are proper mowing, improving soil quality, adjusting your watering schedule, and selecting the right grass species for your climate. With the right lawn care regimen tailored to your conditions, you can sit back with a cool glass of lemonade and admire your lush, enviable turf all summer long.