If you are watering your lawn at night to protect it from the summer heat, lawn care experts have a clear message for you: stop. While setting your smart sprinklers or hose timers to run after dark feels like a convenient, water-saving hack, drenching your grass overnight is actually a lawn care mistake that invites fungal diseases and pests.
The temptation makes sense. Watering away from the sun’s harsh glare and soaring daytime temperatures prevents evaporation. However, what is easy for your schedule is damaging to your grass, leaving moisture to sit on the blades for hours without sun to dry it.
To help with your summer lawn care, we asked leading turf specialists to break down the exact risks of nighttime watering. Plus, if a busy schedule means you must water after dark (and this tripod sprinkler in the Amazon Prime sale is ideal for the job), our experts share the essential damage-control tips to keep your grass healthy, lush, and disease-free.
Why You Shouldn't Water Grass At Night
Knowing when to water grass is often key to it growing well in periods of intense heat and when there's a lack of rainfall.
When it comes to caring for your lawn in June, whilst a timer on a hose or sprinkler system, such as this highly recommended Orbit model from Amazon, is a great idea for busy homeowners, running it overnight is not what the experts advise.
‘While watering your lawn at night might seem convenient, it's typically not the most recommended practice due to one major drawback: the potential for fungal diseases,’ says Ryan Farley, CEO of Lawn Starter.
‘Watering your lawn at night means the water doesn't have a chance to evaporate quickly due to lower temperatures and the absence of sunlight.
'This can leave your lawn damp for long periods, creating a perfect environment for fungi and other lawn diseases to thrive.’
The pores on the leaves of grass open during daylight to expel moisture. If the lawn is watered at night, this process will not happen and can lead to fungal and bacterial growth, plant rot, and even pest problems.
Besides the threat of encouraging diseases and fungi there are other important health and practical issues to consider too.
Gene Caballero, co founder of GreenPal says: ‘Watering at night can create a breeding ground for mosquitos and other pests.’
How to Prevent Lawn Damage When Watering
Sometimes, with our hectic lifestyles, we simply have no choice as and when to do essential chores and watering the lawn certainly falls into this category.
If you do find yourself in this situation, try to give at least a couple hours of sunlight after watering so the blades of grass can dry before nightfall.
Gene Caballero also warns against getting into the habit of watering late in the day. ‘Watering the lawn at night can be harmful if it is done too often or if the lawn is not properly maintained. If you do choose to water your lawn at night, it is important to follow these precautions.
- Water deeply and less often: This will help to encourage the roots of the grass to grow deeper, which will make the lawn more drought-tolerant.
- Water early in the evening: This ensures that the grass has time to dry before nightfall.
- Avoid watering if the temperature is below 50˚F: Low temperatures and cold water can shock the grass.
- Keep an eye out for signs of pests and disease: Treat the problems promptly if they occur.
Gene also advises, ‘If you are using a sprinkler, make sure to adjust the sprinkler head so that the water is not hitting the leaves of the grass.’
This great value sprinkler from Walmart allows you to customise the flow of water and control coverage, so you can use it in large or small yards.
Keeping the grass in your lawn slightly longer can also help to retain moisture so there is less need to water it as regularly. Longer grass traps dew and provides useful moisture for the roots.
Shop Lawn Watering Essentials
An ergonomic thumb-control hose gun like this is good if you struggle with mobility. The 10 spray patterns means it's one of the most versatile nozzles, suiting all your watering tasks.
This sprinkler has adjustable coverage, 3 rotating arms and 12 built-in different angle spray nozzles for controlling the watering range across your yard.
This simple timer makes it easy to water the garden whenever you need. It can use intervals between six hours and a week, and can run for one minute or up to 4 hours.
The Best Time to Water
‘For most lawns, watering between 6am and 10am is best,’ says Teri Valenzuela, Senior Content Strategist at lawn care specialists Sunday.
‘Watering at this time allows for the watering to be absorbed properly, and it’s particularly beneficial to deter disease and prevent heat stress during high temperatures.’
This four-hour window works like magic for two reasons: The morning air is still cool, and winds are usually calm. This means the water actually sinks deep into the soil and reaches the roots rather than evaporating instantly into thin air.
In addition, any water left clinging to the grass blades will dry off naturally as the sun rises. This keeps the lawn dry during the humid evening hours when fungi thrive, but well-hydrated before the afternoon scorching begins.
If you try to water during the blazing heat of midday, you can lose up to 30% of your water to evaporation before it ever hits the soil. Worse yet, water droplets sitting on the grass in intense midday sun can act like tiny magnifying glasses, scorching the blades.
Ultimately, if you are unsure whether or not it is a good idea to water your lawn at night, it is always best to consult with a professional to avoid making any serious lawn care mistakes.
Shop Lawn Care Kit
Of course, even if you want to make your lawn green and thick, there’s no need to water it if the grass simply doesn’t need it, especially in these times of limited water resources.
Michael Deaton, turf agronomist at Pennington Seed Inc adds, ‘Whatever watering regimen you choose, look to your lawn for the final word. Well-hydrated grass springs back up when stepped on. If grass stays depressed, it may need water. Curled grass blades or dull, blue-gray color are signs grasses are water stressed.’
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