[Brassica Blaz]

hi folks,what sort of nutrients are in rain water(if any).because ive always wondered how all the  plants and trees that dont get fertilized manage to grow year after year with the same vigour.is it that they just have deeper root systems? hope i'm making sense it was just a thought!

[Yorkie]

That's an interesting one!

Ground-grown plants do search deeply for water and thus nutrients, so drawing them from the soil.  Rain will probably contain some trace minerals although I'm no scientist.

Deciduous plants will shed their leaves, which rot down to create humus.  Small animals / insects will also die and degrade over time.

[gillie]

If I recall school  biology correctly rainwater contains carbon dioxide and nitrogen is fixed by lightening and washed down - but that can only be a tiny amount.

Wild plants do not grow as fast as cultivated ones.  It is because we push our highly selected plants hard to produce crops that we need to give them fertilizer.

[joyfull]

some rainwater is not good - it can also be acid rain which can weaken plants 

[savbo]

i suppose the big difference is that very little is removed from a natural system, just moved around and up and down through the soil, while we keep taking and taking...

[aelf]

rain is acidic, to varying degree, caused by a reaction between carbon dioxide and water to make carbonic acid. rain falling over or around urban areas will be slightly more acidic as there are more pollutants in the air but these days, acid rain isn't as bad as it used to be.

Many deep rooted plants get most of their nutrients from a symbiotic relationship with bacteria/fungus - the bacteria break down rocks and the plants use the nutrients. Water, in this case, helps to transport the nutrients.

[bigben]

i suppose the big difference is that very little is removed from a natural system, just moved around and up and down through the soil, while we keep taking and taking...

I think you have it Savbo - if we let our veg grow and then left them to die back and rot the nutrients would eventually return to the soil but we keep taking the things home! This is why the soil needs stuff put back. I dont think the rain water has many nutrients in it.

[viettaclark]

But it certainly makes a difference whether you use tap or rain water!! My plants in pots do much better with rain, so there must be something there!!

[aelf]

But it certainly makes a difference whether you use tap or rain water!! My plants in pots do much better with rain, so there must be something there!!

More a case of what isn't in rain water - tap water contains chlorine and flouride which are toxins to many plants

[Goosegirl]

If you think about it, the more you harvest from a plant/shrub/veg or whatever, the more nutrients you need to replace; for example, if you need to regenerate a shrub, you give it a good hacking down, but you must feed it well so that the food goes into the plant to help it regenerate. Also, some things are heavier feeders like beans and brassicas - they will produce but for the best crop they will need extra feeding and of the right sort. Imagine what would happen to trees etc if they were fed regularly - we're so used to seeing them as they are but they would grow even better and bigger! Depends on what you want out of plants.

[Brassica Blaz]

wow! thanks for the info guys!