Magnesium Carbonate?

[creativeprocess]

Is this the usual chemical formulation used in magnesium products?

To supplement a magnesium defiicinecy, which do y'all recommend: foliar feeding or root feeding? Why?

 

[cocktail frank]

It's faster to foliar with Epsom salts, which is magnesium sulphate.

 

[MJPassion]

I've been wondering how well Mag Carb would work as a soil supplement?

Does anybody have experience using such?
If so...
How well does it work?

 

[Mikell]

Glow advocated Mg and Ca carbonates to buffer soft water. He made a few posts here pre-ban and may have gone into greater detail on his website.

 

[corky1968]

Magnesium carbonate is found in dolomitic limestone as CaMg(CO3)2.

So if you use dolomitic limestone you get both calcium and magnesium carbonate.

Dolomite

I'm using some now with all of my plants along with some epsom salts.

 

[Three Berries]

A bit of narcoposting...


Does anyone use magnesium carbonate for pH up as opposed to potassium bicarbonate?

Trying to avoid potassium....

 

[therevverend]

I knew there was a problem with MgCO3 but had to look it up to remember. It's insoluble in water, breaks down very slowly. I prefer Dolomite lime, not just because I like Dolomite (the pimp-I guess I like the mineral too), but because it's 20% Cal and 10% mag. I like adding cal with mag because mag will cause calcium lockout in larger amounts. That way you get a slow release Cal Mag that's going to keep your soil from getting acidic from the various fertilizers. I see it as a 'year to year' type fertilizer rather then a 'diagnose your plants deficiencies or needs and correct' type.

I like it for garden soil, outdoors, as a slow release supplement. I prefer Magnesium Sulfate (epsom salt) indoors or outdoors for much more active quick release. Or Langbeinite which contains potassium, cal, mag, and sulfur for your super blasties. Just picked up some that's 0-0-23. Going to have a lot of fun with it.

 

[therevverend]

Does anyone use magnesium carbonate for pH up as opposed to potassium bicarbonate?

Dolomite is dynamite baby.

 

[Three Berries]

The isolable in water would be what I am looking for actually. Assuming that is, some would be consumed as a buffer and lower the pH while freeing a bit of Mg. It would be OK if the excess settled out.

I have a lot of Ca in my water but not so much the Mg. But I really want to avoid potassium, at least for an experiment.

 

[Three Berries]

Dolomite is dynamite baby.

I use this at times.

Nutirlime DG

 

[Three Berries]

So it apparently is a good pH up. First test was a gallon of rain and 1/2 strength nutes came out 6.1 pH. Added a 1/4 gram of the MgCO3 and it raised the pH to 7.4!. So far at 24 hrs. It does take a while to slowly buffer. It is a very light powder.

I'm running an experiment now with three gallons of 6.1 rain and .5, .75 and 1 gram added to see what they do.

A slurry with excess added and distilled water is reading at 9.7pH but hasn't sat overnight. Going to filter it and test the clear solution tomorrow.

 

[Three Berries]

Looks like the top end buffering limit is 9.7pH.

Had three gallons of rain water at ~6.2 and 20 ppm. Rain water is very hard to get a pH reading on. But I let the probe sit in the water for a good 5 minutes on each, rinsing with distilled between and they all read 6.2.

Added 1/2, 3/4 and1 gram to them yesterday. 1/2 gr was 9.4 this morning and the other two were 9.7. The 9.7 were a bit cloudy yet so some MgCO3 is still unreacted, hence the 9.7 Ph or buffer limit.

Today I added a 1/2 teaspoon of my Miracle Grow Bloom Buster, what I use for flowering, 10-52-10 Half strength for indoor. I let that sit a bit and see what's it settles out to.

But I have two plants with stubbornly low pH runoff. around 5.9. Yesterday I ran rain water though one I have in veg as it was locked out for Mg apparently, 2 gallons through a 1.25 gallon container. Didn't change the pH at all. Did lower the ppm. I also have a flowering one in the same shape pH wise. Been running nothing but rain water though it.

So I pHed the water for both to 7.4 with the MgCO3 and 1/2 nute water for the final flush. The run off for both was much higher at 6.3 for the veg and 6.6 for the flower. PPM was under 1000. I'll water them next with rain and see if the pH holds.

But it appears if you want to use MGCO3 for pH up it works great with very little needed. 1/4 gr or so to the gallon for a big change. It's a lightweight fluffy powder. A leveled 1/2 tsp was .33 gr.

 

[Three Berries]

I watered the flowering one again last night using rain and adding some of my homemade calmag. The run off pH held at 6.6. but ppm was up to ~1400. This morning the buds were very frosty. It's still a bit pale compared to it's younger sister. The younger one has had a steady pH the whole time and is now bigger.

The veg one I flushed too is holding the pH at 6.3.

What I have been using in the past is potassium bicarbonate for pH up. It takes quite a bit though. Generally two or three teaspoons per gallon of nute mix.

The MgCO3 at a 1/4 gr per gallon hardly raises the ppm count at all, only ~50 ppm.

 

[Creeperpark]

Looks like the top end buffering limit is 9.7pH.

Had three gallons of rain water at ~6.2 and 20 ppm. Rain water is very hard to get a pH reading on. But I let the probe sit in the water for a good 5 minutes on each, rinsing with distilled between and they all read 6.2.

Added 1/2, 3/4 and1 gram to them yesterday. 1/2 gr was 9.4 this morning and the other two were 9.7. The 9.7 were a bit cloudy yet so some MgCO3 is still unreacted, hence the 9.7 Ph or buffer limit.

Today I added a 1/2 teaspoon of my Miracle Grow Bloom Buster, what I use for flowering, 10-52-10 Half strength for indoor. I let that sit a bit and see what's it settles out to.

But I have two plants with stubbornly low pH runoff. around 5.9. Yesterday I ran rain water though one I have in veg as it was locked out for Mg apparently, 2 gallons through a 1.25 gallon container. Didn't change the pH at all. Did lower the ppm. I also have a flowering one in the same shape pH wise. Been running nothing but rain water though it.

So I pHed the water for both to 7.4 with the MgCO3 and 1/2 nute water for the final flush. The run off for both was much higher at 6.3 for the veg and 6.6 for the flower. PPM was under 1000. I'll water them next with rain and see if the pH holds.

But it appears if you want to use MGCO3 for pH up it works great with very little needed. 1/4 gr or so to the gallon for a big change. It's a lightweight fluffy powder. A leveled 1/2 tsp was .33 gr.

How are you testing your rainwater pH to get ~6.2 and 20 ppm?

 

[Three Berries]

With my Aperea pH pen and ppm stick. It's all I got and I don't really care how accurate it is at that point. But if left in the water long enough it usually bottoms out around that, but not always sometimes it's higher.

Whatever gets to the rain water first will be dominate and that is what this does. MgCO3 is insoluble in water but I can get about 30-40 ppm to dissolve and raise the pH to ~9.7(max) and the ppm to ~50 ppm from ~20 ppm. A gallon takes 250 mg to max out on the rain.

It reacts with the loose H+s in the rain. When doped above the 50 ppm it just settles out as excess on the bottom but maintains the ~50 ppm.. I added 3 grams to a gallon of 440ppm well water to settle down a hot one I had in flower right now. But the excess MgCo3 goes in with the water as a solid.

I'm planning on three cups well water to make a gallon of rain and then doped with a 1/4 gr MgCO3 as my standard water unless issues arise. My hard water is ~440 ppm and ~ 90/10 Ca/Mg, pH7.4 and a touch of iron.

Kind of like 'minerals added for taste' on bottled water. Great way to take the 'edge' off rain or RO and stay away from calcium or potassium.

 

[Creeperpark]

With my Aperea pH pen and ppm stick. It's all I got and I don't really care how accurate it is at that point. But if left in the water long enough it usually bottoms out around that, but not always sometimes it's higher.

Whatever gets to the rain water first will be dominate and that is what this does. MgCO3 is insoluble in water but I can get about 30-40 ppm to dissolve and raise the pH to ~9.7(max) and the ppm to ~50 ppm from ~20 ppm. A gallon takes 250 mg to max out on the rain.

It reacts with the loose H+s in the rain. When doped above the 50 ppm it just settles out as excess on the bottom but maintains the ~50 ppm.. I added 3 grams to a gallon of 440ppm well water to settle down a hot one I had in flower right now. But the excess MgCo3 goes in with the water as a solid.

I'm planning on three cups well water to make a gallon of rain and then doped with a 1/4 gr MgCO3 as my standard water unless issues arise. My hard water is ~440 ppm and ~ 90/10 Ca/Mg, pH7.4 and a touch of iron.

Kind of like 'minerals added for taste' on bottled water. Great way to take the 'edge' off rain or RO and stay away from calcium or potassium.

When using a pocket pH testing meter one must have at least 120 ppm in the water or the results will most likely be false. The reason is the lack of electroconductivity in water. So when you say you are testing rain without any ppm in it you are misreading the pH. Using regent pH solutions one can test pH without ppm in the water.

 

[AllStuff420]

In general, one of the best ways to treat magnesium deficiency in a plant is to spray the plant's leaves with a magnesium-containing solution, such as Epsom salt dissolved in water. Another option is to include compost, Epsom salt, or another magnesium source into the soil.

 

[Three Berries]

When using a pocket pH testing meter one must have at least 120 ppm in the water or the results will most likely be false. The reason is the lack of electroconductivity in water. So when you say you are testing rain without any ppm in it you are misreading the pH. Using regent pH solutions one can test pH without ppm in the water.

I should just ignore what the pH comes out to? What if I add a half a gram of nutes and it's still under 120 ppm?

If it can't tell what I got then why does it show a change? How can I get rain water with a ppm count from 15 to 40?

 

[Three Berries]

I'm not adding the magnesium for a deficiency but rather for buffering without potassium.

 

[Creeperpark]

I'm not adding the magnesium for a deficiency but rather for buffering without potassium.

Just wait to check the pH after you've added enough ppm to get an accurate reading. When you say you have a pH at as little as 20 or 40 ppm you are misreading the correct pH. A lot of growers do the same thing not knowing about pH electroconductivity and pocket meters. .Hey, you are still doing good job TB.