Dolomite Lime and Coco Coir(Good or Bad?)

[justiceman]

Hello everyone I would like to know if it is advisable to add dolomite lime to a soilless mix with a coco coir base.

Here is a base mix I just put together that is nice and simple but I have not added any rock powder minerals to it yet. It's basically a play on Coots Mix:

1 part Coco Coir
1 part Perlite
1 part Earthworm Castings

I have the following amendments on hand that I plan to add. These proportions are from LC's Recipe #1:

1 tablespoon Blood meal per gallon or 1/2 cup per cubic foot of soil mix
2 tablespoons Bone meal per gallon or 1 cup per cubic foot of soil mix
1-tablespoon kelp meal per gallon or 1/2 cup per cubic foot of soil mix

For a peat based mix I typically add powdered dolomite lime at 2 Tbsp per gallon or about 1 cup per cubic ft.These days coco coir is easier for me to obtain so I'd like to make this work. I'm aware that dolomite lime has a pH near or at 7 and acts to neutralize acidic soils which helps with peat based mixes since peat is acidic. I'm just wondering if there would be a negative effect that dolomite would have on a coco coir based mix.

If I cannot use dolomite would other mineral sources be advisable such as oyster shell flour, or gypsum? I want to keep this as an organic grow and would really like to avoid using liquid fertilizer if possible.

 

[Lightweight]

I did an organic grow with coco using dry amendments in 30 gallon fabric pots growing pepper plants and mostly used gypsum for my calcium source with just a little bit of dolomite lime and they grew really nicely.

I'd guess from memory that it was around a 8:1 or 7:1 ratio of gypsum to dolomite

 

[justiceman]

I did an organic amendment grow with coco in 30 gallon fabric pots growing pepper plants and mostly used gypsum for my calcium source with just a little bit of dolomite lime and they grew really nicely.

I'd guess from memory that it was around a 8:1 or 7:1 ratio of gypsum to dolomite

I was thinking gypsum would be a good choice for coco coir. It's nice to hear that you had some good experiences with it. Thanks for chiming in

 

[Lightweight]

I was thinking gypsum would be a good choice for coco coir. It's nice to hear that you had some good experiences with it. Thanks for chiming in

Sure thing!

I also used Stutzman's Farms Sup 'R Green 3-2-2 chicken manure compost, Stutzman's Farms Nutri-Rich 4-3-2 chicken manure pellets, fortified alfalfa pellets (rabbit food kind), Jobe's Organics Vegetable and Tomato granular fertilizer, magnesium sulfate and Sul-Po-Mag. I'm pretty sure that was it. I'll give it a try on cannabis too. I just haven't got around to it yet. I'm sure it'll work just as good for cannabis as it did for the peppers though.

 

[KIS]

I'd probably go 25% dolomite and 75% gypsum if I had to guess without a soil test. You most likely don't want to use too much dolomite because it's easy to supplement Mg with epsom salts if low (much harder to lower than raise a nutrient), and dolomite will raise pH while gypsum will not. Since coco coir has a neutral pH you will already be high is my guess (7.2 or higher).

 

[justiceman]

I'd probably go 25% dolomite and 75% gypsum if I had to guess without a soil test. You most likely don't want to use too much dolomite because it's easy to supplement Mg with epsom salts if low (much harder to lower than raise a nutrient), and dolomite will raise pH while gypsum will not. Since coco coir has a neutral pH you will already be high is my guess (7.2 or higher).

That sounds like a fair and safe approach. I had been considering some kind of a mix of the two recently. The above comment by Lightweight got me thinking about it. Sounds like a good way to cut down the carbonates and excess Mg in the dolomite lime. Soon I will run some auto's with that ratio and see what happens. Thank you for chiming in!

 

[Teddybrae]

I would caution against understanding that ALL Dolomite on the market has the pH you state. I have found some products more active than others. One variable is how finely ground is the Dolomite? Fines will interact more quickly than coarse-grained product.


I know nothing about Peat, but I mix local soil and coco using a small amount of fine dolomite. Probably about a clenched hand-full to 2 gallons or ten litres. One cup to a gallon would be too much! And don't forget any shortfall later in the plant's life can be remedied with organic foliar application. eg: cal+mag+boron is available here in Oz.


If you make soil too alkaline it is very difficult to remedy.


Good luck!

 

[bsgospel]

So we're pretty much talking about a water-only coco, is that right? I'd like to check that out. Are you going to start a new thread or will this go with your other water-only thread? What brand/variety of bone meal do you use again?

 

[Teddybrae]

I thought later that you must not know a lot about soil pH. A pH of 6.5 - 7 is ideal. Warning: your Dolomite may go 14!!! So be careful.


Buy a Soil pH Test kit. They're less than $20 at the hardware or garden supplies. Test around your house garden until you understand what you're seeing/doing. Then test your mix.


Mix well ...

 

[St. Phatty]

I thought later that you must not know a lot about soil pH. A pH of 6.5 - 7 is ideal. Warning: your Dolomite may go 14!!! So be careful.

Buy a Soil pH Test kit. They're less than $20 at the hardware or garden supplies. Test around your house garden until you understand what you're seeing/doing. Then test your mix.

Mix well ...

What if you had a mixing container with a cubic foot, 8 gallons, about 32 liters of soil.

Fox farm Ocean Forest, with added nutes. A medium amount, 8 ounces of bone meal (1/4 liter), maybe some bat or seabird guano (though I prefer to save those for compost tea).

Anyway, a soil medium that tends to run slightly acidic - how much lime would you add - just guessing ?

I figure a 1/2 cup of Lime would be safe, to counteract the acidity from the rich blend of nutes.