New Grower Aluminum sulfate

[Wasp]

Ok long story short did my mixes and added a little to much compost and need to lower ph level from 8.0 to about 7.0 maybe 6.5 around that area btw I won't be starting my seeds in this mix transplanting after they're roughly 3 weeks in (autos ) but just simply placing the bio degradable into the 5 gallon bucket but in those three weeks I need to lower my soil level I'm really considering aluminum sulfate as a last resort because of how toxic it is but reacts so quickly so please help me

 

[jingo]

Hey Wasp

I've used aluminum sulfate in my outdoor vegatable garden. You really need to know whether cannabis can uptake aluminimum. Do you have any of the big grow encylopedias. How about peat moss? I use that outdoor to lower ph. Perhaps if you dried it and ground it up somehow.

 

[jingo]

So I did some quick research on pub med aluminum is Def bio available in cannabis so I would consider peat moss or something simular.

 

[Wasp]

Huh funny lol I'm using sphagnum peat moss in my mix already and the ph is hot but I'm using a shit meter that prong one for like ten bucks I'm gonna get the capsules and test em again and see btw I haven't ran any water into the soil mixes yet btw so might be that too

 

[Muddy]

Aluminum sulfate is very effective at lowering the pH of soil. I use Pro Mix which is usually 7 right out of the bag. I've found that adding 4 grams of aluminum sulfate per gallon of soil will lower the pH to 6.3 - 6.4. As the soil dries out the pH will slowly rise back up to around 6.7, but will go back down again with the next watering. I've been using it for about a year now and have not seen any adverse effects on the plants or the quality of the smoke.

 

[w89]

Dont know why the hell anyone would want to use aluminium sulphate in their soil mix, why not use regular sulphur? Its calcium sulphate, much better that aluminium ...

 

[Muddy]

Dont know why the hell anyone would want to use aluminium sulphate in their soil mix, why not use regular sulphur? Its calcium sulphate, much better that aluminium ...

Sulfur takes to long to become active in the soil. It is a better alternative if you premix your soil and let it sit for at least 2 months before use. AS is immediately available. If you add sulfur to soil being used to grow autos it won't have any effect until around week 6 or 7 of the grow. By then you will likely be experiencing pH lockout issues.

 

[az2000]

I use Pro Mix which is usually 7 right out of the bag. I've found that adding 4 grams of aluminum sulfate per gallon of soil will lower the pH to 6.3 - 6.4.

Muddy, do you use dolomite lime? I.e., does alum. sulf. interfere with it, or is it redundant to use both?

I'm a little confused on lime. I've read dolomite stabilizes ph, pulling ph (whether high or low) to a constant level. But, I also read that it's used to raise ph.

I use Pro-Mix HP and add 20% potting mix and 20% perlite. So, if I do alum. sulf, I'd probably start small, like 1-2 grams (per gal medium) in a couple pots. See how it goes. I'm just unclear why I'm using dolomite if it's sending ph up, but Pro-Mix should be more down.(?)

 

[dingo]

I am keen to learn how to reduce PH in coco. The mix I get is premixed, buffered, perlite etc but is PH 7.0.

I use PH down and water @ PH 5.0 in attempt to bring down the PH. However with limited success. The local hydro shops seem to think PH 7.00 works without issues in the growing community and they look surprised for asking about reducing the PH to 5.5 - 6.0.

If I prepared my coco in a 5 gallon pot/22 litre, I guess I should add 25 grams of Alum sulphate and mix well? Does it need to sit or is it instantly ready for seedlings.

My grows work out OK for me but hoping I can increase the yield with better PH in soil.

 

[Muddy]

Muddy, do you use dolomite lime? I.e., does alum. sulf. interfere with it, or is it redundant to use both?

I'm a little confused on lime. I've read dolomite stabilizes ph, pulling ph (whether high or low) to a constant level. But, I also read that it's used to raise ph.

I use Pro-Mix HP and add 20% potting mix and 20% perlite. So, if I do alum. sulf, I'd probably start small, like 1-2 grams (per gal medium) in a couple pots. See how it goes. I'm just unclear why I'm using dolomite if it's sending ph up, but Pro-Mix should be more down.(?)

Since Pro Mix already contains lime so I don't add any additional. Lime does raise the pH and it does help to stabilize it. Enough is added to Pro Mix to bring it to a neutral pH of 7. Adding additional lime would likely push it higher, which we know isn't necessary. The aluminum sulfate doesn't conflict with the lime. Do you have a good soil probe like the Accurate 8? If not, I would suggest getting one. They are about $50 and worth every penny. I would suggest making up a batch of your mix, watering it with water pHed to 6.5, wait a day and check the pH with the probe. See what you're reading and then I can probably give you an idea of how much AS to add.

I am keen to learn how to reduce PH in coco. The mix I get is premixed, buffered, perlite etc but is PH 7.0.

I use PH down and water @ PH 5.0 in attempt to bring down the PH. However with limited success. The local hydro shops seem to think PH 7.00 works without issues in the growing community and they look surprised for asking about reducing the PH to 5.5 - 6.0.

If I prepared my coco in a 5 gallon pot/22 litre, I guess I should add 25 grams of Alum sulphate and mix well? Does it need to sit or is it instantly ready for seedlings.

My grows work out OK for me but hoping I can increase the yield with better PH in soil.

I've not personally grown in coco but I don't see why the AS wouldn't work with it as well. I would suggest doing the same procedure as I just outlined above. Make up several small pots of mix and add different amounts of AS to each. If it reacts in coco the same as in Pro Mix, which I suspect it will, then probably about 6-7 grams per gallon of mix will be needed to bring it down to a good level for coco. Again, you will need a good soil probe to do this type of test.