Why does rain make plants grow so much better than...

[sao123]

I've sufficiently watered my lawn && vegetble garden every day through this non-raining period we've had recently. I even tried to use some miracle grow. but my plants just didnt grow very well. Its been hot and sunny, perfect for plants.

However, its rained here (cloudy, no sun) the last 2 days because of some storms and the remnants of katrina, and now my plants are growing like wildfire.

I dont get it, whats so special about rain? must be all that acid and pollution making my plants grow.

[ahurtt]

It really depends on the kind of plants you are talking about and what specific weather conditions they favor most. Hot and sunny is not the ideal growing condition for all plants. Some plants like shade more while others like sun. Some grow better in more moist or damp climates and others grow better in drier areas. Some like it hot, some like it cooler. The acidity and alkalinity of the soil also affects how plants grow. Look at a water lilly compared to a desert cactus. Maybe it's not the tapwater vs. rainwater, but the weather conditions in general. Plus a good rain will saturate the ground and refill the water table with water far better than running a garden sprinkler for an hour or two. Plants, like people, are different.

[imported_Tick]

You could experiment with a misting system for your plants, to see if humidity creates better growth.

[Cattlegod]

It might have something to do with the fact that it stays hydrated for a longer period. I mean when you normally water plants it drops a lot less water and can be absorbed by the surrounding land.

[herm0016]

rain also has a lot of nitogen in it because the atmosphere is mostly nitrogen. lightning also puts nitrogen into the water droplets.

[Soccerman06]

I dont know, why does my lawn grown like 3" when we have a decent rain and pritty much 1/2" when I use the sprinklers.

[Calin]

The tap water contains lots of minerals, some of them being not so good for plants (salt content can in the long end destroy the land if water even a bit salted is used). This is more important with sprinker systems (that vaporize a bigger fraction of the sprinkled water before even reaching the plants/soil. Maybe the grass likes it a bit colder (an effect of the rain) than the temperature in full sunlight.
If you could try an underground irrigation system or maybe a "droplets" irrgation system it would be better (and consume less water too)

[Calin]

The tap water also contains traces of chlorine. That's why when using tap water for plants, it is better to leave it in an open container overnight

[mrzed]

One of the reasons is that tap water is usually much colder than rain water. The cold water lowers the soil temperature, which has a significant effect on growth rates. That and the above mentioned chlorine effect are probably the two main reasons.

[derftsur]

I have seen a number of answers, the simplest one would be that Rain by itself does do some added good, but the major element is when there is lightning. All know that nitrogen is required for plants to grow. With lightning and rain, the lightning sets the nitrogen into the soil. It is believed that the electrical charge at ground level causes this. Some plants have been known to start from No plants above the ground to more than a foot tall in 6 hours when rain and lightning is active. Nitrogen is necessary, but more important is the availability of this nitrogen for the plant to grow. Setting the nitrogen into the soil is the single most important factor for most growth of plants of all kinds.

[PsiStar]

One year I had the presence of mind to water my tomato plants with A/C condensate. I did move the end of the tubing around a bit and did fertilize. That has been the best year ever for my tomatoes.

The condensate was pumped up from the basement by a condensate pump specifically made for the job. The water flow rate varied with the outside temp ... the hotter it got, the more the tomatoes were watered.

[notposting]

One hell of a first-post necro-bump there