SOIL When diluting hard water with RO is extra magnesium via epsom salts usually required?

[static]

Hi all, greetings from rural Waterloo region, ON!

I live in a part of the province that feeds a lot of the rest of our province. There are farms and fields in every direction that as far as I know do just fine with the regions tap water.

But this being said -- it's extremely hard out here. Around 330 PPM from the tap currently.

I saw in another thread that target PPM for cannabis is somewhere around 100, so I use 10L RO to 5L Tap and this puts me right around 100-115PPM.

My question is this: without knowing the exact concentrations of calcium and magnesium in our tap water (I've checked the regions website, sadly they only test for heavy metals and lead), and knowing that we have extremely hard 330PPM tapwater diluted down to around 115PPM with RO, would supplementing additional magnesium be required with epsom salts?

I just picked some up after seeing conflicting forum posts online and am still unsure on this

Big thanks again for any advice, cheers!!

[Orggrwr]

I have no idea but maybe try a grow with Epsom and another without and see which your plants like. Or maybe start without and only add Epsom if the plants show a deficiency. Good luck and happy 4/20.

[Mollisol]

If you are growing in soil your tap water should be fine. You will need to adjust the Ph to between 6 - 7. Other than that I don't see any problem.

[9fingerleafs]

My water from the tap it's from a deep well, it's 700ppm. Completely unusable. It's mostly sodium because I live two miles from the beach. So there's no way to know for sure what's in the water. I wouldn't use it at all just to have real control over nutrients. But if you want to I think you should follow the advice above. Only add if you see deficiency. Depending on the light and the soil / hydro nutrients you may need magnesium or calcium. Only time will tell