What's happening here: deficiency?

[bobrown14]

NO do not use magnesium in your soil to grow plants.

Can use it in a foot bath for you! Highly recommend.

Crane - your water pH is too high. You should leave it sit out or even better bubble it with fish tank air pump and an air stone. That will help.

Elemental Sulfur is a good way to lower soil pH - go VERY VERY EASY with it. Plants actually need it to live as well, but its a MICRO-nutrient. Meaning a little goes a LONG WAY.

Try not to use chemicals to lower your pH. Those same chemicals are not that great for the soil micro-organisms.

Plants use photosynthesis to help feed them selves.
This process includes the leaves and chlorophyll.

Chlorophyll molecular make up is :

C55H72O5N4Mg <--- see the Mg on the end there. Only 1 molecule. So not a lot is need to grow weeds or any other plant. If you are in soil, likely the soil has enough Mg in it for plants.



Soil-less medium is of course different. CalMag and all that jazzy stuff is not for use in soils. Yup true.

 

[Crane]

So I got a water report for our tap water. It has 20 mg/liter calcium and 1,7 mg/liter magnesium. Is that a low level? I also bought this Canna Calmag- buffer additive that will raise the calmag-level slightly,would it be a good idea to use? I watered today with pure spring water. At least the plants haven't gotten worse!

 

[bobrown14]

I would not use any buffers. Likely too much Magnesium total in soil plus the water. Nothing you can do about it cept filter it out of your tap water.

I see this all the time. There's a Mag toxicity and it looks like Calcium deficit so people put on Cal-mag and things get worse instead of better so more cal-mag.

Then plant pretty much is gone.

I would continue with your spring water and see how things go. It takes several days to see results.

Then go easy with your tap water - collect rain water even better and use that.

Steer clear of cal-mag and those sorts of things.

Cal-mag how come thats only sold to cannabis growers. Its like some sort of magic potion for magical plants but its only one plant??

Better off using some silica way better off. Soil comes from rocks, silica 95% of all rocks and 59% of earth crust.