Should You Water Plants at Night? What a Gardening Pro Thinks

Nighttime watering is okay in a pinch, but it may promote pests and diseases. Most garden experts agree that plants grow best with early morning or early evening watering.

If you want to avoid common plant pests and diseases and grow healthier indoor and outdoor plants, here are a few simple watering tips to help you water at the perfect time, every time.

When Should You Water Plants?

The best time to water plants is generally in the early morning, between 5 a.m. and 9 a.m., although plants also grow well when they’re watered in the late afternoon to early evening.

If plants display signs of water stress, like wilted leaves, they can be watered at other times of the day or night, but avoid making a habit of watering plants at night or when the sun is high overhead.

Regular nighttime watering can promote the spread of plant diseases and pests, while watering when the sun is at its peak can lead to water waste.

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4 Reasons Not to Water Plants at Night

If your plants have started to wilt and droop, it’s okay to water parched gardens at night. But regularly watering plants after dark can lead to some serious problems, like pests and diseases.

Here are four reasons why it’s best to avoid watering at night, if you can help it.

• Plant diseases. Fungal plant diseases arise when gardens have poor airflow and plant leaves stay wet. Since evaporation rates slow down at night, nighttime watering can spread diseases, like mildew, sooty mold, and leaf spot.
• Pests. Slugs and snails come out after dark, and they’re especially active when the soil is moist and plant leaves are dripping with water. Unfortunately, watering at night can make your garden more appealing to these pesky pests.
• Slower absorption. Plants stop photosynthesizing when the sun sets, which means they aren’t as able to absorb soil moisture after dark. If you want your plants to take full advantage of the water you give them, it’s much better to water in the morning.
• Increased risk of overwatering and underwatering. It’s harder to monitor the output of drip irrigation lines and soaker hoses at night, which can lead to overwatering and potential root rot.

Why Watering in the Morning Works Best

Morning watering gives plants more time to absorb soil moisture, but it also reduces water waste and helps prevent plant diseases, like powdery mildew.

If you’re still on the fence about morning watering, here are a few reasons why it’s worth a try:

• Water conservation. Water evaporates faster during hot weather, so you can lose a lot of water to evaporation if you water your garden on a hot afternoon. However, temperatures are usually a bit cooler in the morning and the evening, which gives plants more time to absorb the water they need.
• Plant leaves dry faster. When you water in the morning, your plant leaves have the entire day to dry off before night falls. This can reduce the incidence of plant diseases, like leaf spot and powdery mildew, but it also makes plants less attractive to slugs and snails.
• Temperatures are cooler. Working outdoors in the middle of the day when temperatures are soaring can make gardening much harder. But if you water your plants early, you can avoid sweating under that scorching noonday sun.
• Easier monitoring. Watering in the morning reduces the chances of overwatering since you can easily watch how much water your plants receive and adjust your watering schedule accordingly.