Top dressing with dolomite lime / oyster shell flour

[tentgrower]

I've got 12 girls going in 3 gallon fabric pots of roots organic soil and I did not mix in any dolomite lime or oyster shell flour to address long term calcium needs to get my girls through the flower cycle.

Can I top dress the girls with dolomite lime or oyster shell flour to serve as a slow acting calcium supplement? Or should a simple liquid cal mag supplement added to my fertilizer regimen do the job?

Thanks!

 

[Satyros]

It will take several weeks to get worked in and if you are using sunlight it could easily become an issue.


If you do top dress, don't rely on it, I would boost it in the meantime with something.

 

[Easy7]

Oyster should really be pre-mixed in the soil. Lime, I'd go light top dressing that. This late in the game a liquid application is best.

Perhaps a fermented plant extract. They have lot's of calcium. As well as guano, guano has a good bit of calcium.

 

[FunkBomb]

Yes you can topdress and get the calcium and magnesium to the plant. What you need to do is top scratch it in with your fingers. The topmost half inch of soil. You can also mix the powder in water and shake like hell and then apply. It takes a day or two but with regular waterings it gets into the rootzone. There is a mix from Roots Organics called Elemental that works quite well.

-Funk

 

[Dawn Patrol]

use agricultural gypsum, it's much more readily plant available.

Get the fine dust if you can, if you can only find pelletized grind it up.

As FunkBomb noted, work it into the top half inch of soil.

for a 3 gallon pot I'd start with 2 tablespoons and see how it goes from there. If you get too much in your mix, the excess calcium could start locking up some of your other nutes.

 

[Klompen]

I strongly second the notion to use gypsum. I rarely had issues with magnesium in the past, but a quick epsom foliar works wonders. I realize its not considered "organic" but I have found that very few things deliver magnesium as effectively as epsom and none of the alternatives are anywhere near as dirt cheap.

 

[Teddybrae]

With all respect to those before me here ... Gypsum does not supply Calcium. Dolomite supplies both Calcium and Magnesium.
I have used Dolomite successfully as suggested above. Scratch into soil and water in. BE CAREFUL not to put on too much! it is next to impossible to rebalance pH if you do. Just put on a sprinkle like sugar on a do-nut and wait a week to see if you need more.

 

[Klompen]

Gypsum does not supply Calcium

No offense, but what on Earth are you talking about? Gypsum is calcium sulfate....

 

[Lost in a SOG]

Gypsum doesn't supply magnesium.

Unless your pH is crazy low you shouldn't be low on Mg.. Gypsum also doesn't raise pH except in parts of the soil that have become very acidic which it will then react with. It's a really useful quick way of supplying Ca..

Dolomite takes a little while to react and it is the particle size that decides how quickly it reacts..

 

[Klompen]

Here is a really good article on the benefits of gypsum

https://www.usagypsum.com/wp-content/uploads/2016/04/AMI-tech-general.pdf