Watering with Cold Water VS Warm Really Make a Differerence?

[garden5]

I've heard quite a few folks say that they let their water warm up before they use it on the garden. I've even got a neighbor who told me that the cold well water isn't good for plants. Does the cold water really make a noticeable difference compared to warm water?

[Ladybug027]

From what I understand cold water shocks the root system. HTH

[orgoveg]

I've never heard that. Everyone I've known to garden in my whole life has used water straight from the well or municipal system (unless they had a rainwater collection barrel or some other irrigation method).

I would think that any impact on the roots would be negligible. Just as plants "harden off" when placed in different weather conditions, they would probably become accustomed to regular cold waterings.

Possibly container gardening is a little different as that soil would get much warmer during the day and maybe cold water could have more impact. Just thinking out loud

[sheeshshe]

huh. I always just spray from the hose out of the well. never thought twice of it. hmmmm...

[gixxerific]

I use cold water in fact I let the hot water sitting in the hose get out before spraying.

If you could look at my garden you wouldn't see a problem. With as hot as it is here it might even help cool them off. Not an expert on watering temps but my garden is doing great with cold water.

[soil]

I spray the boiling hot water out( daytime hose water), then use the warm water and eventually it turns cold. ive seen no difference in the areas that got warm and the rest cold.

[TWC015]

I've never noticed any problems using "cold" water on plants. The water temperature in the summer here is about 70°F.

I also let the hot water come out of the hose before I use water on the plants. Even if the water in the hose is cool, I still like to let the plants get fresh water. By the time the water goes through the soil and gets to the roots, I doubt there is much difference in temperature either way. Also, rain is quite cool as well and it doesn't cause problems. I've never noticed any ill effects from rain when the temperatures are in the 30s either. The plants probably don't care what the temperature of the water is as long as they have enough.

[Bobberman]

A hose in the sun or even water running through a heated hose can damage plants! The temp reaches as much as 150 or above and can even burn you! What I remember reading years ago is that water containin air is harder for plants to absorb! Why I don't remember but I have mentioned it before and most disagreed with me! Cold water holds more air!
+++
There was a experiment with seeds in a closed bottle. The bottle that had heated cooled water with little air in it and a bottle with more air in the water were used. The seeds grew faster in the bottle of water with less air! Why does anyone know?

[Ladybug027]

I looked it up in wiki and this is what I found. I think it was refering to house plants. I use rain barrel water so I never thought much about it, interesting topic

Does hot or cold water affect plant growth?

While ice cold water can shock the roots of a plant, hot water can actually be worse.
Boiling or near boiling water can damage the fine roots of plants, inhibiting water take-up by the roots.
Room temperature water is best, especially for watering house plants.
If you have a dried-out peat based potting soil, warm (not hot) water can help the peat to re-hydrate.

Hot water on foliage can also be detrimental - many leaves are sensitive to direct extreme temperatures, which is one reason that boiling water can be an effective organic herbicide to treat small weedy tasks, like grass growing in sidewalk cracks.

[Francis Barnswallow]

As brutally hot as it is here, the first water that comes out of the hose is VERY hot. It then "cools" to a reasonable temp, thats when I water the garden.

I was told that the cool water is good for the plants.

[rainbowgardener]

Well, I think it needs to be clarified, what and when we are talking about. In early spring, the hose water here is VERY cold, barely liquid, and would not be good to put on tender plants that are just getting used to outdoors.

Right now, as other people have said, the hose water at least initially is VERY hot and also not good to put on plants, until you get to the part that was not in the hose or in surface pipes.

So it depends on the season, the weather, and how hot or cold the water is.

[Jeffross1968]

Maybe I'm wrong, but rain is typically cold, right? I mean...I've never been hit by rain and said, "oh my god, I'm burning!!!".

So, if the rain can be cold, I'm guessing any water you put on will not be too cold. I use a very deep mountain well, and the water that comes out after the warmed hose water is quite cold, even in the middle of summer. There has been no effect that I have found....

[cynthia_h]

Maybe I'm wrong, but rain is typically cold, right? I mean...I've never been hit by rain and said, "oh my god, I'm burning!!!".

So, if the rain can be cold, I'm guessing any water you put on will not be too cold. I use a very deep mountain well, and the water that comes out after the warmed hose water is quite cold, even in the middle of summer. There has been no effect that I have found....

Although you don't give your location, the fact that you are using a "very deep mountain well" tells me that you do not live in the, say, tropics.

For three years, when I was 10 to 12, we lived in Panama, in the Canal Zone. Panama experiences monsoon-like torrential rains during the "rainy season," which lasts seven months of the year. During these rains, the prevailing 95% or so humidity becomes 100% and walking outside is like walking into the shower at your house. Yes, indeed: the water is warm, not cold or cool. It is not refreshing in the least. But the plants and birds and all that evolved to thrive in the tropical climate love this warm rain, to judge from all the birdcalls we heard in the afternoons when the rain started up.

Rain in Florida during the summer was similar. Hot or warm water, sticky with humidity. Bleah. (Tampa/Sarasota area) A cool rain would have been very nice, but noooooo....

Not all rain is cool, not all rain is warm. Hose water can be very cold or very hot. I've kept plants alive during a hard freeze by watering them with warm water from the watering can (filled inside the house and walked outside late at night). I've kept them alive during a heat wave by watering them with cool water from the watering can (filled inside the house and walked outside as needed).

It's not a "one-answer-suits-all" type of question.

Cynthia H.
Sunset Zone 17, USDA Zone 9

[young scientist]

The real question we should be asking is not weather hot or cold water makes a difference. I can see that some of you are from hot environment and of course it would make sense to use colder water, and vise versa.

My question is if it is appropriate to use water as an adjustment to outside temperature? If it is cold outside is it good for the plant to be watered with warm, or relatively hot water, and vise versa? Does this really affect their growth or well being, or will the outside temp just dominate everything?

[jal_ut]

I would be careful to not use water from a hose lying in the sun. That could be too hot. However water from the well or water main should not be any problem. Over much of the earth the temperature of water from wells is around 50 degrees F. That should be no problem at all.

[imafan26]

I think if you are talking about watering a garden from a hose, you want the water to be comfortable and not steaming out of the pipe.

However, if you are talking about hydroponic systems though, keeping the water at around 70 degrees may actually help the plants grow. When you water the plants you are only affecting their environment for such a short time that you probably won't impact their overall growth unless you go to extremes, like pouring hot water on them.

My grandmother had a Bartlett pear tree in Kalihi, which is in the middle of the city and hot and dry. To keep it alive, it was grown in the shade and every day they emptied the icemaker ice on it to keep it cool. Because the cold ice was on it for hours it probably did impact it. It still wasn't all that happy since Hawaii really isn't a good place to grow Bartlett Pears.

[Gary350]

Do as mother nature does. It never rains hot water. Soil temperature is always cooler than air temperature.

[Stefano]

I know that it depends from wheater conditions and temperature. For example in summer it is better for the plants to be not watered with cold water, because it could be caused a thermal shock, specially if you wet the leaves. In fact during the summer it said that is better if the plants are wet in the morning or in the evening when the environment temperature is still not too hot.