Dolomite Lime and Coco - pH problems?

[Apical Bud]

Hey everyone!
I am trying coco again after using peat moss for the past few years. I got in trouble with coco awhile back when I treated it like soil and also used organic nutes. This time it's back to miracle grow.

I am using cheap brick coco, and rinsed it, let it sit over night, then "charged" it in a solution of dolomite lime (calcium carbonate and magnesium carbonate). After my last rinse in clean water I put some in a pot and tested run off. pH was 6.2ish and ppm were about 20-30 (my tap ppm).

So that seemed great to me. I've been watering seedlings with about a 200 ppm solution buffered to 5.7 for about a week. Well, I noticed today that when I watered heavily that the run off looked like coca cola. The ppms were abou 400, but the ph was 7.3!

I thought I washed out all the dolomite lime that wasn't stuck to the coco. Do you think this pH is just residual, previously undissolved dolomite lime that has finally dissolved, or am I missing something?

Anyone ever used coco and dolomite lime?

 

[Cali.Grown>408]

Straight coco? No but a 50/50 mix with peat and coco.. and every 5 cubic feet I throw a bag of ammended soil in there too. I never checked my ph though and things were going smoothly.
When u said you treat coco like soil were you letting it dry out? I’d water once or twice a day once the roots fill out the pot it was twice a day. I don’t use lime anymore tho I use oyster shell now

 

[Apical Bud]

Straight coco? No but a 50/50 mix with peat and coco.. and every 5 cubic feet I throw a bag of ammended soil in there too. I never checked my ph though and things were going smoothly.
When u said you treat coco like soil were you letting it dry out? I’d water once or twice a day once the roots fill out the pot it was twice a day. I don’t use lime anymore tho I use oyster shell now

Yeah when I used it the first few times I would water it every other day
I've stayed away from crushed shells because they don't have magnesium, but I use epsom sals anyway so....

 

[kotobide]

Hey everyone!
I am trying coco again after using peat moss for the past few years. I got in trouble with coco awhile back when I treated it like soil and also used organic nutes. This time it's back to miracle grow.

I am using cheap brick coco, and rinsed it, let it sit over night, then "charged" it in a solution of dolomite lime (calcium carbonate and magnesium carbonate). After my last rinse in clean water I put some in a pot and tested run off. pH was 6.2ish and ppm were about 20-30 (my tap ppm).

So that seemed great to me. I've been watering seedlings with about a 200 ppm solution buffered to 5.7 for about a week. Well, I noticed today that when I watered heavily that the run off looked like coca cola. The ppms were abou 400, but the ph was 7.3!

I thought I washed out all the dolomite lime that wasn't stuck to the coco. Do you think this pH is just residual, previously undissolved dolomite lime that has finally dissolved, or am I missing something?

Anyone ever used coco and dolomite lime?

Without knowing the age and size of your plants im wild guessing here that you are feeding/watering small amounts each time on new seedlings that cant absorb the ppm you are giving them and as they absorb water your nutes are just building up in your coco swinging your ppm and ph. They really don't need much nutrients that early on i would cut back to 25% while the cotyledon leaves are still in tact as they provide the nutrients the plant needs during this stage.

 

[hotrodharley]

Dolomite lime takes a looong time to break down.

 

[JavaCo]

Peat is acidic so it needs to have something to bring up the PH like lime or oyster shell, but coco is pretty much neutral so liming it is going to make the PH go too high. I would try gypsum if your going to use 100% coco it is PH neutral and will add calcium and sulfur for the plants.

 

[churchhaze]

They really don't need much nutrients that early on i would cut back to 25%

Stop telling noobs to starve their plants!

im wild guessing here that you are feeding/watering small amounts each time on new seedlings that cant absorb the ppm you are giving them

Drop a seed in fertile soil and it will burn to death? Please feed your seedlings!!!

 

[kotobide]

Stop telling noobs to starve their plants!



Drop a seed in fertile soil and it will burn to death? Please feed your seedlings!!!

Like I said i t was a.guess without knowing a lot of variables. If he's got a root system somewhat established he should be feeding to 20% runoff daily. But if he just.popped seedlings he shouldn't be burning them up with a crap ton of nutrients.