Can You Water Plants With Cold Or Hot Water?

All gardeners agree that watering is immensely beneficial to plants of all species. Still, there are several questions and misconceptions being spread among the community regarding the watering process, including what constitutes the most efficient way to do it and whether you can water plants in the sun. Getting the right answers to some of these questions can be crucial if you’re looking to grow a healthy, long-lasting crop.

You should not water plants with cold or hot water, as doing so can cause severe physical and cellular damage to them. Hot water may boil cell walls, resulting in loss of turgidity, wilting, and death. Cold water can cause dormancy, slow or stop plant growth, or outright kill your plants.

The temperature of the water used to water a plant at any stage of its life can have tremendous effects on its quality and health, which is why it is necessary to understand exactly how hot and cold water affect plant growth. The rest of this article highlights these effects, the proper temperature water should be to ensure your plants thrive, and all you need to know about watering plants in hot and cold weather.

Effect Of Hot Water On Plants

You can tell the water you’re using on your plants is hot if its temperature exceeds 120 oF (49 oC). Watering plants with water at these temperatures regularly will heat their cell walls, destroying them and killing the plants in the process. Plants with damaged or dead cell walls will lose their turgidity, causing the cells to shrink and then dry out.

In addition to dehydration, a loss of turgidity will mean the plant will lose its ability to hold water, resulting in physical damage to the foliage. Hot water will also cause general wilting, brown and shriveled leaves, dry flowers, and weak stems.

The hot water can also scald the foliage of plants and melt leaf cuticles. The cuticle is the waxy layer covering the leaves of plants, and a loss of this layer will expose the most vulnerable parts to the elements. Therefore, a loss of the cuticle may lead to a higher occurrence of illnesses, pathogens, and pests in your system.

Furthermore, extreme water temperatures can scald and burn leaves on contact, which may even cause the plants’ leaves to fall off.

Using hot water to water plants also has adverse effects on soil and the root systems of some varieties. The high temperatures may kill beneficial microorganisms in the soil, leading to a deficiency in essential minerals like nitrogen. They can also prevent plants from absorbing water and nutrients in the ground by damaging their root and absorption systems.

Additionally, hot water can interfere with a plant’s ability to perform critical biological processes, including respiration and photosynthesis. The heat may also damage the xylems of the plants, which will affect capillary action and transpiration.

High watering temperatures might also impair seed germination by causing damage to the seed coat or scalding the shoot of seedlings. However, the amount of damage hot water may cause to seeds and seedlings depends on the type of plant in question.

Cool-season seeds can grow in temperatures ranging from 55 to 70 °F (13 to 21 °C), whereas warm-season varieties require water temperatures between 70 and 85 °F (21 to 29 °C) to ensure proper germination.

However, hot water can be beneficial to plants, depending on the temperature of the water and the frequency and duration of the watering process. Many plant pests can be efficiently killed by watering at high temperatures for short periods, and most plants can endure being submerged in hot water for a few minutes.

Additionally, you can kill insects like mealybugs, scales, and mites by submerging plants in water heated to a maximum of 120 °F (49 °C) for no more than eight minutes. This process will cause no harm to the plants if done correctly.

Hot water can also help remove sticky spots and other contaminants from leaf surfaces. However, avoid using hot water to water the leaves and shoots of plants directly.

In essence, although the ambient temperature of the plants’ habitats plays a crucial role in how well they can thrive within a system, the water temperature used when watering is equally essential to the plant’s overall health.

Effect Of Cold Water On Plants

Watering your plants with cold water can cause severe damage to their overall health and affect their growth cycle. Primarily, cold water can cause shock to the plants, disturb their natural biological processes, and cause abnormal responses to external environmental stimuli.

The water you’re using for your plants is too cold for them to thrive if the temperature drops below 62 °F (17 °C).

Although cold water affects plants similarly to hot water, it mostly messes with a plant’s biological processes and causes very little physical damage to the leaves and stems on contact. Low temperatures cause plant cells to freeze, causing structural damage to root and shoot systems and disrupting the flow of nutrients and water in the plant.

However, the most critical effect of cold water on most plants is that it may confuse them, causing them to hibernate and become dormant. This hibernation results from the low water temperature shocking the plants’ roots, activating a helpful reaction to low winter temperatures when it is not needed.

In the winter, some plants lie dormant to preserve their energy and nutrients for development in favorable conditions. Their growth rate slows down dramatically during this time, and some plants may completely stop developing to conserve resources for the future efficiently.

Like other species on the planet, plants need water and essential minerals to develop and thrive. The absorption of these essential minerals is governed by transpiration and capillary action processes. However, alongside the phloem, the xylem is a critical organic pathway responsible for absorbing and transporting these nutrients throughout the entire plant.

Plants absorb water by capillary action through the xylem. The xylem is a structure made up of tiny tubes right beneath the surface of the stems. Water is drawn upwards from the soil by the molecules in this structure, allowing the plant to stay hydrated.

The phloem is a living tissue in plants that carries photosynthates, which are soluble organic molecules produced during photosynthesis to various areas of the plant. These organic molecules include sucrose, an essential organic compound used by all living organisms. This type of transportation is referred to as translocation.

Watering with cold water may harm a plant’s cells by freezing them, causing critical damage by disrupting the tissues transporting water and essential minerals.

Generally, the live xylem usually is far more impacted by the cold than the phloem tissues. This damage  usually happens because the xylem tissue usually doesn’t go dormant. Therefore, the low temperatures will cause plants to have blackened shoots, develop withered roots, and experience tissue loss.

For this reason, cold water may result in wilting, severe snow breaking, blackened leaves, salt damage, and a variety of other problems. A lack of nutrients and water may also cause plants to suffer desiccation, a myriad of other cold-related injuries, and even death.

In essence, watering plants with cold water will cause them to act as they would in winter, and not all plants are built to survive at low temperatures. Your plants will usually look pale and starved, indicating low nutrient uptake and use. Furthermore, using cold water to irrigate flowering plants may hinder them from blooming.

How Does Water Temperature Affect Plant Growth?

It’s no surprise that many environmental factors must be monitored and controlled to ensure that plants thrive. After all, even humans and animals need their immediate environment to provide certain conditions to ensure their survival. However, plants are especially vulnerable to fluctuations, and extreme environmental changes such as these can have a tremendous impact on their metabolic activity and biological processes.

Water temperature affects plant growth by influencing major biological processes. These processes include transpiration, photosynthesis, translocation, and the capillary action process used to absorb water and nutrients through plant roots.

Generally speaking, cooler temperatures tend to slow down life processes in plants, while warmer temperatures may affect turgidity and cause cellular damage. Water temperature affects aquatic plants, seeds, houseplants, and even vegetable cuttings.

These effects have been discovered through the extensive work of scientists like Lori R. Tolley-Jordan, who performed essential experiments with wild rice and published conclusive reports showing that cooler temperatures can affect the success of the shoot system of the plant.

Photosynthesis and respiration are usually the first processes affected by high water temperatures. As a result, the plant stops developing since it depletes resources faster than they can be replenished. Low temperatures also affect photosynthesis, decreasing the process rate and slowing the plant’s growth cycle.

It’s important to note that the temperature of the surroundings has a more significant impact on plant development than the temperature of the water used in watering. Extreme ambient temperatures encourage plants to develop more quickly, but they also can harm the flowering and seedling stage of the plant’s life cycle.

Furthermore, thermal pollution may cause changes to the population density of hydroponic and aquatic plants, encouraging certain  species to thrive in warmer climates.

What Is the Ideal Water Temperature When Watering Plants?

When watering your crop, the water’s temperature plays a crucial role in ensuring they turn out well. Therefore, you’ll want to ask yourself: “What temperature range is best for your plants?”.

When watering plants, the ideal water temperature ranges between 62 and 72 °F (17 and 22 °C). The optimal temperature required by most varieties to thrive is 68 °F (20 °C). Temperatures that fall way off this range could significantly stunt your plants’ growth rate.

There are various ways you can quickly get water at suitable temperatures for your plants. The best sources include tap water, rainwater, distilled water, and softened water.

However, you should always make an effort to precisely measure the temperature of the water before you use it on your plants, especially if you live in locations with extreme temperature fluctuations or harsh weather.

You can use any kind of thermometer to check the temperature of the water before use. You may need to let the water run for a few seconds before sticking the probe into it, but when you do, you’re guaranteed an almost 100% accuracy.

Furthermore, it would help to invest in a soil thermometer to ensure the plant root system and microbes are operating at the correct temperature before and after watering.

Is It Better To Water Plants With Hot Or Cold Water?

Although it’s always necessary to use room temperature water for all plants, some varieties may benefit from extreme temperatures. For example, tulips like cold water and flower more often in extreme temperature fluctuations. However, what kind of water is more beneficial to most plants?

It is better to water plants with hot water rather than cold water. Hot water is preferable because most experts and experienced gardeners agree that it might help get rid of some pests and stains, among other benefits, while cold water will usually only adversely affect the plants.

You must make sure to use water that does not exceed 120 °F (49 °C) so as not to cause damage to the plants themselves. However, you’re better off not treating your plants using this method as it may not be as effective as using a pesticide to get rid of pests such as aphids.

Watering Considerations

In addition to ensuring the water used is always at the correct temperature, you need to ensure the watering process is done as efficiently as possible. Therefore, knowing optimal watering times and signs is necessary to ensure the water itself and water temperature are not damaging your plants.

Water your plant in the morning or evening, before or after the sun rises or sets. Temperatures around this time will limit evaporation and ensure that the plant obtains sufficient water via capillary action. You should also water the plant often to keep the soil from drying up.

Watering your plants in the morning is generally preferable to watering in the evening since the plant will dry up well before the sun sets.

Water tends to sit in the dirt, around plant roots, and even on the foliage due to prolonged low temperatures at night. This moisture can lead to decay, fungal growth, and insect infestation.

You should also take care not to overwater as this may affect the support of the plants and cause them to fall over or grow awkwardly. Overwatering can also cause some plants to lose their drought resistance and wilt if the soil water moisture content drops.

Check for wilting to see whether a plant has been properly hydrated. However, certain herbs will appear to wither in direct sunshine as a means of conserving moisture and rehydrating when the temperature lowers in the evening. Temporary withering is the term for this phenomenon.

The age of a plant will also influence when and how frequently you should water it. Seedlings require as much water as possible, as long as they’re not drowned in liquid. On the other hand, mature plants need less water since their root systems are more extensive and their shoots are more robust.

Tips For Watering Plants

Watering is as much of a science as it is an art. The success of the plants in your system depends on how effective your watering practices are and the quality of the water you use. Therefore, while you should be cautious about the temperature of water you apply on your plants, you should also be mindful of the method you choose while doing so.

Here are some helpful tips to perfect your watering technique:

  • Ensure you water your plants first thing in the morning.
  • Don’t use too much or too little water on your plants.
  • Make sure the soil and plant roots get enough water.
  • It would be best if you watered potted plants daily.
  • Allowing the plants to lie in moist or damp soil for an extended period can lead to fungal infections, which can cause significant injury or death to your plants.
  • You should make sure to plant your plants in well-draining soil to avoid root rot.


Water temperature can have a considerable effect on your plants. You should not water plants with cold or hot water, as doing so can cause severe physical and cellular damage to them. When watering plants, the water temperature should be between 62 and 72 °F (17 and 22 °C).

However, if a choice is necessary, it’s preferable to water plants with hot water rather than cold water because it might help eliminate pests and stains, among other benefits.

Alexander Picot

Alexander Picot is the principal creator of, a website dedicated to gardening tips. Inspired by his mother’s love of gardening, Alex has a passion for taking care of plants and turning backyards into feel-good places and loves to share his experience with the rest of the world.

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