In this article we take a look at what time of day is best to water plants, according to evidence.
- What time of day is best to water plants?
- Watering plants in the morning vs evening
- What is the worst time to water plants?
- Does it matter if you’re watering indoors or outdoors?
- Watering at the best time when you can’t be there in person
- Pro tips for efficient plant watering
The best time to water a plant, either indoors or outdoors, is first thing in the morning or during the late afternoon or early evening. There are pros and cons to either, but also lots of neat solutions for watering at the best time, even when you can’t be there in person!
What time of day is best to water plants?
The gardening community is generally divided into two camps. Those who water first thing in the morning, as soon after the sunrise as possible. And those who water in the evening around sunset. Both camps are trying to achieve the same thing: watering when the temperature of the soil and air is coolest, and their plants are not in direct sunlight.
Some plants even need watering in both morning and evening. For example:
- During a heatwave, or if you live in a region which is typically very hot in summer.
- If they only have a limited volume of soil to establish a root system in, for example a small or very densely planted pot.
- Or if they’re growing in a hanging basket, which can lose water through evaporation from below as well as above.
But most plants only need watering once a day, and many plants in the ground don’t even need watering every day. Over-watering can actually cause more problems than it solves. For example leaching minerals and nutrients away from your plants, and increasing the risk of rot at the base of the plant. Once you’ve established how often your plant needs watering, you’ll need to pick a strategy: are you Team Dawn, or Team Dusk?
Watering plants in the morning vs evening
There are pros and cons to either approach. For a start, one of them might simply suit you better. If you work shifts, you might not be at home to water in the evening. If you have kids to get to school, then your morning routine might already be full to capacity. Remember that growing plants is meant to be fun, and water at any time of day is better than no water at all. So don’t overthink the possibility of another time being better, if one option is all you have. If you’re blessed with the luxury of choice, let’s see what the other advantages of morning and evening watering are.
Advantages of watering plants in the morning
Watering first thing in the morning, as early in the dawn as possible, means soil temperatures are at their coolest, and the water will sink down deep into the ground.
Watering in the morning also strikes a great balance between getting most of the water into the soil, but also enabling the surface of the soil to dry off again quickly when the sun gets higher. This is valuable because when the surface of the soil stays damp, humidity at the base of the plant creates ripe conditions for fungi and bacteria to invade the plant. Tomato blight is a classic example of an infectious plant disease which takes hold when the soil around the base of the plant is constantly wet.
Watering early in the morning means most of the water sinks to the roots, and then a dry crust forms on the surface of the soil when the sun comes up, reducing the risk of moisture-borne diseases.
Advantages of watering plants in the evening
Watering in the evening also takes advantage of cooling soil temperatures. So most of the water soaks down to the roots of a plant, rather than evaporating away.
Some research has also indicated that plants use water more efficiently in the afternoon and evening, and that evening-watered plants put on growth more quickly.
Watering containers in the late afternoon/evening is also thought to help regulate the soil temperature by helping to bring the temperature back down at the end of the day, thus reducing stress on the plants inside.
What is the worst time to water plants?
It’s generally not a good idea to water plants in the middle of the day, especially if the weather is warm and sunny. There are a couple of reasons for this:
- Firstly, it’s inefficient. Water will evaporate from the surface of the soil rapidly, reducing how much sinks down to the roots.
- Secondly, water splashes on foliage in the hottest part of the day can result in scorch marks. Scorch marks spoil the look of your plant, and large amounts of scorch damage can even cause the plant to struggle or die back.
What time is evening and when is afternoon
Afternoon and evening can mean different things to different people, so what’s the earliest time it’s safe to water your plants?
The answer isn’t clear cut. It will depend on your region, the time of year, what kind of weather you’re having, and how much shade is cast across your yard by boundary features such as trees or fences. As a rule, it’s a good idea to hold off watering plants until they are no longer in direct sunlight.
Does it matter if you’re watering indoors or outdoors?
Do these considerations apply equally to indoor plants and outdoor plants?
Yes in some cases, but not all. We’re much more able to control the microclimate around our houseplants. So it’s often possible to water a houseplant in the middle of the day, by moving it out of direct sunlight first. For houseplants in large pots, which are difficult to move, it’s smart to water them first or last thing though. And for plants which don’t like water sitting on their leaves, such as begonia amphioxus it’s best to water them early in the day.
Remote plant watering solutions
What if your work or your family commitments mean that watering at the perfect time of day isn’t possible? Don’t worry! There are lots of potential solutions for watering your plants on time, wherever you are. From state-of-the-art automatic plant waterers, to low-tech irrigation ideas which haven’t changed in millenia.
Drip irrigation systems
A drip irrigation system is a perforated hose which runs from an outside tap and all around your plants. Systems can be connected together to cover large or small gardens. A timer can be fitted between the tap and the hose, so that the system only comes on when you want it too. This is the most sophisticated kind of automatic waterer, with the biggest set-up cost, but it has a long lifetime, and requires the least maintenance once set up.
Ollas and irrigation pots
Ollas and irrigation pots like the ones in the video near the top of this page are permeable clay pots which you sink into the ground next to your plants. Once filled with water, the water gradually soaks out into the soil, providing a steady supply of moisture to your plants, right at their roots. This is a great solution for minimizing water loss through evaporation. It also keeps the surface of the soil dry.
Capillary matting is a dense felt-like material, which is great at wicking water up from a reservoir and into a plant pot. These days, there are lots of self-watering plant pots on the market which rely on capillary action to extend how long your plants last between watering. You’ll need to remember to check the reservoir regularly though.
Pro tips for efficient plant watering
Picking the right time of day isn’t the only way to make your plant watering as efficient as possible. Follow these tips as well, to make sure you don’t waste a drop of water.
- Mulch the surface of the soil with organic matter, or if looks aren’t important, plastic membrane. Apply the mulch in spring while the ground is still damp, to trap the moisture in the soil.
- Water plants directly at the base of the plant using a watering can without a rose, or drenching nozzle on a hose. Targeted watering is much more efficient than wafting a fine mist or spray about, which mostly lands on the foliage. For plants which don’t like wet surface soil, water from below using saucers or one of the methods above.
- As a rule of thumb, one inch of water sinks 6 inches into the ground. For plants in the ground it’s better to water thoroughly and less frequently, than a little everyday. Watering occasionally but deeply encourages plants to put down long roots, which makes them less reliant on watering in the long run. Watering little and often promotes shallow roots, which makes the plant very ill-adapted to drought. Pots are different – watering them with about 10% of their volume a day is a good starting point, then adjust up or down as required.
- Collect rainwater. Collecting rainwater using water butts or even just buckets left out during a shower will provide you with an additional supply of free water when the weather is dry. Rain on its own sometimes isn’t enough to water container plants, especially if they have big leaves which catch the raindrops and send them over the edges of the pots instead. So buckets of rainwater can be tipped straight into containers. Some plants grow better when watered with rainwater than tap water too!
What is the best time of day to water plants – summary
The best time to water plants is first thing in the morning, or last thing in the evening. Each has it’s advantages, and if you have enough time, you might choose differently for different plants in your garden. For container plants and hanging baskets, you might even choose both! Just avoid watering in the middle of a hot sunny day. Not only do you risk scorching your plants, lots of the water will evaporate and you won’t get much results from your hard work.
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Cheng. Plant-Microbe Interactions Facing Environmental Challenge. Cell Host & Microbe. 2019.
Idaryani et al. Effect of mulch application and watering frequency on growth and production of chilli. IOP Conference Series: Earth and Environmental Science. 2021.
Warren & Bilderback. Irrigation timing: effect on plant growth, photosynthesis, water-use efficiency and substrate temperature. Acta Horticulturae. 2004.
How plants use water. West Virginia University Extension. Accessed September 2022.