How much lime?

[Surfer Joe]

I am using canna terra pro plus soil that is supposed to have a few nutes and a lime charge to stabilize its ph, but I wanted to add a little more dolomite lime because last time the soil was about ph 5.9 and the leaves looked unhealthy.
The bag says to add a 1/2 pound of it for every square yard, so I assume that they mean to sprinkle that on the ground in that amount?
But how does that translate into pots?
How much would you add to the soil for a 20L pot?
Thanks for any advice.

 

[Hushpuppy]

I'm surprised no one has answered this. It may have got missed. I would add about 3Tbsp to that pot and work it into the soil. Then in 6wks do it again unless they show some deficiency of the magnesium, in which case you would add it sooner.

 

[Surfer Joe]

Thanks a lot. I was thinking that it was more for maintaining the pH of the soil than as a nute source.

 

[Hushpuppy]

Ok, yeah it actually does both. Dolomite lime is good for maintaining the pH AND as it breaks down on organics, it supplies magnesium and calcium to the plants.

 

[Droopy Dog]

*I* use a bit more, 1cup/cf (7.5 gallons), added to my mix. This translates to 2Tbl/gallon of mix.

Since it has "some" lime in there, perhaps a bit less. But if the pH was 5.9, it couldn't have been much of a charge ...........

It's hard to overdo lime, but easily under applied (5.9 pH). My pH floats around 6.8 with the amount I use.

Wet

 

[orangesunshine]

I grow 5 gallon buckets of dirt...one handful of lime is equivalent to almost a cup and im about 2 weeks to harvest... probably should have limed sooner but what the heck...better late than never I guess

 

[Surfer Joe]

Thanks for all the suggestions. I'd like to keep the soil around 6.5.
Does the buildup of nutes in the soil raise or lower the ph over time?
Does something like canna flush help to restore the soil ph?

 

[Hushpuppy]

If you are running organic soil and nutrients, you will not have nute buildup, you will have nute depletion. If you are running synthetic nutrients in the soil, you can get nutrient buildup, or nutrient salt buildup. Both of these can and will change the pH in the soil but the direction depends on which elements build up. If you are using synthetic nutrients then I would suggest at least one good flush about halfway through the grow to clean out the soil. But if you are doing organic nutrients in organic soil then you should never have to flush unless something gets really messed up like dumping a boatload of worm castings onto the soil during the flower phase and it starts burning the leaf tips.

I'm not sure about the canna flush as I have never used it myself but it may be a good product. I think most of the flush products are supposed to grab ahold of the elements in the soil so that they can be more easily washed out during the flushing but I have never used them myself.

 

[Surfer Joe]

Thanks. I'm not sure what I'm using. I copied the info from the bag and was wondering if you or anyone could advise me on whether this is an organic soil or not, and how best to approach feeding plants growing in it. I'm using the nutes from the same brand as the soil.
The only thing I've added to the pure soil is some perlite and a bit of dolomite lime.
All I know is that it drains quite well.

View attachment soil-info.jpg

 

[Hushpuppy]

It appears to be an organic soil but it also has a mineral fertilizer charge which would be considered synthetic unless they specify that it was chelated through organic methods. I would say to stick with the Canna nutrients for this grow and see how it goes. You could also contact the manufacturers and ask them if any of the nutrients are chelated organically or if there is nutrient salts present in them. It sounds like it may be some but possibly not enough to create a problem with salt buildup.