Rain water PH

[TheCat]

Hello,

last week I measured the PH of rain water I had stored in 8 liter plastic bottles and it was over 8. During the rainy season measures were around 6.5. It is approximate as I use liquid reaction.

After a couple of minutes of interaction with gpt things got clearer. We have had several days with high Sahara dust concentrations, which carry calcium carbonates, phosphates, amongst other particles. Seems this has affected the PH. I am also surrounded by large constructions sites, I am thinking all the dust created can have an effect as well as they use lots of cement and gypsum.

Just wanted to share this issue.

cheers,

 

[kaeptn_kush]

Rain water is nice, mostly ver soft. But rain water has a lack of minerals. So I would mix rain water with tap water.

 

[Tom bolenate]

Hello,

last week I measured the PH of rain water I had stored in 8 liter plastic bottles and it was over 8. During the rainy season measures were around 6.5. It is approximate as I use liquid reaction.

After a couple of minutes of interaction with gpt things got clearer. We have had several days with high Sahara dust concentrations, which carry calcium carbonates, phosphates, amongst other particles. Seems this has affected the PH. I am also surrounded by large constructions sites, I am thinking all the dust created can have an effect as well as they use lots of cement and gypsum.

Just wanted to share this issue.

cheers,

Rain water is very good for PH stability but it lacks minerals...especially calcium.
So 50/50 tap/'rain water is best.
This must be adapted to your tap water hardness...the more hardness the less % of tap water in the mix.
Ot 100% rain water with regulars calmag application.

 

[charlesufarley]

I use nothing but spring water and have for over 40 years now. It is among the softest water you will ever find, almost zero mineral content. I have to change out the anode rod in my hot water heater every 3 to 5 years because of this. And it's fairly acidic but I've never actually measured the pH of course, as I don't monitor anything but temperature and humidity. Claude let me know Appalachian rainwater is generally acidic.

Every every year when I recycle my soil, I always throw in a couple of handfuls of dolomatic lime and Epsom salts to balance the ph and provide calcium/magnesium. I've never used a cal-mag supplement because I've never needed to.

 

[Mate Dave]

I don’t pH the rain as it’s falling worst bit about rain is it’s usually very cold and at the very end of the hot spell it kicks up dust and cools the ground considerably and reduces oxygen content of the soil.


Where you store it how long the water is stored how it’s what it’s collected from etc. I’ve a lot of RWH they’re usually better when black and slimy on the inside and of a certain size and you want to keep it recirculating with a siphon or and have a sediment filter. The pH fluctuations is mostly down to detritus decomposition and the sediment in the storage vessel

 

[Mate Dave]

This one I have here was new in a few months back. Collected that in about 30 mins recently
This IBC is maybe 8 years old.

It’s not much different the rainwater to the village spring water with TDS that I collect for drinking most days after it’s drained through all the volcanic rock etc. This is safe to drink tho I use this drinking water I autoclave for propagation. Last time I cleaned this out was in 2018. It’s still testing safe I just collected this. I’ll pour a few glasses out and drop in some testing solution and report back.

 

[PennyP]

Hey brothers, maybe this is a stupid question, but I've been thinking about putting a rainwater barrel outside in the garden to collect rainwater.

So far, I've always been a little hesitant about using rainwater for my indoor plants. What's your experience with it?

Obviously, if the water is clean and of good quality, that's great. But I've always had some concerns about using untreated rainwater. For example, what if there are mosquito larvae, fly larvae or other insect larvae in it? Those are definitely things I don't want ending up in my indoor setup.

Do you guys use collected rainwater and mixing barrels for your outdoor grows, or is it perfectly fine to use rainwater indoors as well?

Maybe it's a stupid question, but honestly, I don't know much about this.

One love, blessings and peace!

Penny

 

[charlesufarley]

This one I have here was new in a few months back. Collected that in about 30 mins recently View attachment 118323View attachment 118324
This IBC is maybe 8 years old.

It’s not much different the rainwater to the village spring water with TDS that I collect for drinking most days after it’s drained through all the volcanic rock etc. This is safe to drink tho I use this drinking water View attachment 118325I autoclave for propagation. Last time I cleaned this out was in 2018. It’s still testing safe I just collected this. I’ll pour a few glasses out and drop in some testing solution and report back.

That volume of rain in 30 minutes, wow. That's almost like what we got during Hurricane Helene.

 

[Mate Dave]

@ Charles I live near the confluence of 2 rivers with large dams. Recently we got 2500l per m2 in 2-3 hours and that didn’t even put a trickle in the river. During last winter the dam at the bottom of the garden burst and turned into a personal NFT system

That IBC collects of the Pigsty/ chicken shed roof which collects off another roof, the combined collection area is large so it fills fast. Unfortunately there isn’t much space.

If running a living soil indoors then you need rainwater.

If I was using canna or similar and not mixing and feeding within 30 mins I would prefer tap water that is buffered. That’s sort of why they mix RO and Tap.

I have some filters inside my blue barrels to stop sediment and insects blocking the lines Penny. My neighbour a way a way has fish and frogs in their deposit that deal with insects. They drain it every day and it fills at night while it’s also irrigating from the well.

If you can use free water use free water Penny. I’ve been mixing up the mains and well water all most of the season just because it’s not easy to deliver a lot of water fast and deep off one system and one is cooler than the other what makes a difference.

 

[Swifty]

I only use rainwater in my grows, it seems logic to use since every plant outside gets it.
You do have to make sure that the quality stays consistent.

Like Mate Dave mentioned:

Where you store it how long the water is stored how it’s what it’s collected from etc. I’ve a lot of RWH they’re usually better when black and slimy on the inside and of a certain size and you want to keep it recirculating with a siphon or and have a sediment filter. The pH fluctuations is mostly down to detritus decomposition and the sediment in the storage vessel

I have a 15000L concrete cistern in the ground to collect rainwater in. The water comes only from my roof.
There is an overflow to the sewers so with every rain there is fresh water mixed in with the rest.
The temperature is fairly stable throughout the year.
I have a coarse filter, fine filter and active coal filter just behind the pump.
This systems works for me.
Even in summer time, when the level gets low for 1-2 months, I dont see or smell any changes in the water.
If you have good bacteria in your cistern your water will not smell bad or have bad properties.

Fresh collected clean rainwater should always be good to use imo.
Keeping and storing it is more challenging.

 

[charlesufarley]

I only use rainwater in my grows, it seems logic to use since every plant outside gets it.
You do have to make sure that the quality stays consistent.

Like Mate Dave mentioned:


I have a 15000L concrete cistern in the ground to collect rainwater in. The water comes only from my roof.
There is an overflow to the sewers so with every rain there is fresh water mixed in with the rest.
The temperature is fairly stable throughout the year.
I have a coarse filter, fine filter and active coal filter just behind the pump.
This systems works for me.
Even in summer time, when the level gets low for 1-2 months, I dont see or smell any changes in the water.
If you have good bacteria in your cistern your water will not smell bad or have bad properties.

Fresh collected clean rainwater should always be good to use imo.
Keeping and storing it is more challenging.

We use a n underground 1500 gallon /5678 liter cistern to collect spring water for storage that supplies the house. Hurricane Helene fucked it bad, as you can see. Had to have a guy with a track hoe come in, dig this one out and put another one in:

 

[Mate Dave]

Here’s some nerdy type stuff. It explains that pure water is neutral at 7.47 or something and how temperature causes certain fluctuations. Adding some chemistry to pure water would enable it to retain some stability or buffer for a period of time but nothing beats a fresh supply.

Edit: It’s helpful when you add the link Dave

Temperature Dependence of the pH of pure Water

chem.libretexts.org

 

[Uncle Jack]

Rain water is very good for PH stability but it lacks minerals...especially calcium.
So 50/50 tap/'rain water is best.
This must be adapted to your tap water hardness...the more hardness the less % of tap water in the mix.
Ot 100% rain water with regulars calmag application.

Could I not add dolomite lime to my soil mix and use tank water?

 

[Mate Dave]

Could I not add dolomite lime to my soil mix and use tank water?

What are you looking to do Jack? There might be better ameliorants to add.

 

[Tom bolenate]

Could I not add dolomite lime to my soil mix and use tank water?

I should have said '' you must ensure to provide calcium to your plants'' calmag is just one way among others.

 

[quinxstar]

many years i used only rain water never add something i just use fertilizer the bloom only in veg i like more rempoting

i have 2 X 1000 liters and a little one of 300 liters