Having problems growing in coco for the first time.

I switched to Cocotek Coco Coir because I was told this stuff is much better than the soil I was using and is pretty much plant and go. Well it has actually been the most problems I've ever had occur in such early stages of the plant. I started out by not feeding them the first week, but then they started to yellow around the edges. I was told this was a deficiency so I started feeding them per the schedule provided with the House and Garden Cocos A&B nutes which is 2.5mL of each per gallon during the first week. So far some have improved by many still have problems. This is all under a 600w HPS, 18/6 light schedule, and about 82F temps. Here are the pics:

Is this one over-watered? Under-watered? I had heard it was almost impossible to over-water in coco.



Is this a nute burn or nute deficiency?



Here's an example of one that looks just fine. Why so much inconsistency among the plants?




Please help coco experts out there! I know this can be better and I don't want to have to go back to Foxfarm soils.

looks like lack of nutes or too much water or getting too hot

brewing said:

looks like lack of nutes or too much water or getting too hot

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The one does look overwatered but Ive watered them less than i did with soil. I thought it was harder to overwater with coco? Do you think i should feed them some more then? How much should i increase the dosage?

Can anyone help?

highasfvck said:

The one does look overwatered but Ive watered them less than i did with soil. I thought it was harder to overwater with coco? Do you think i should feed them some more then? How much should i increase the dosage?

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1st one def overwatered. I just started in coco myself and its not this miracle anti-overwater medium. Your mix looks like it has alot of fine coco in it, so its actually retaining water very well. I put about 25% perlite in mine to help with drainage, but it can still hold alot of water. Id put a towel or paper towel under the pot to help absorb some of the water faster.

Kinda looks like maybe calcium def on the first one? 2nd maybe the same? Maybe your pH is off? Coco isnt exactly the same as soil with what all gets absorbed into it and not. Your pH should be around 5.5 - 6.0 with coco. And runoff isnt that accurate for checking pH with coco.
Maybe its getting too hot? But this not being your first grow I would imagine you would have that figured out.

growdown said:

1st one def overwatered. I just started in coco myself and its not this miracle anti-overwater medium. Your mix looks like it has alot of fine coco in it, so its actually retaining water very well. I put about 25% perlite in mine to help with drainage, but it can still hold alot of water. Id put a towel or paper towel under the pot to help absorb some of the water faster.

Kinda looks like maybe calcium def on the first one? 2nd maybe the same? Maybe your pH is off? Coco isnt exactly the same as soil with what all gets absorbed into it and not. Your pH should be around 5.5 - 6.0 with coco. And runoff isnt that accurate for checking pH with coco.
Maybe its getting too hot? But this not being your first grow I would imagine you would have that figured out.

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What is the best way to pH coco then? Im pretty sure theyre not too hot because I have not had these same problems before. Especially so early on. Should i try feeding them more before they get worse?

highasfvck said:

What is the best way to pH coco then? Im pretty sure theyre not too hot because I have not had these same problems before. Especially so early on. Should i try feeding them more before they get worse?

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Well I guess you could do the same method used for soil. 1 part coco + 3 parts or so of water. I tend to look at my mixture before water and then check the runoff and run an average. So my water is 5.8 w/ nutes added and come out at 6.1 at runoff, so I figure im around 5.9 - 6.0 at the roots. Not sure how this is going to pan out, but besides 1 plant having issues the other 2 look great. Course the 1 bad one is probably being attributed to my pH being way off from seedlings.

Also Ive been reading alot that coco absorbs calcium so you might need to add cal/mag to your nutes to help with this. But Id check your pH first and go from there. I wouldnt go straight to feeding yet, cause if its a pH issue you will just lockout more nutes by feeding more. Maybe your plants didnt enjoy full strenght nutes right away, or at least a couple of them. But if all else fails, you can flush and add nutes slowly. And it looks like those things needs to dry out a little more between waterings.

Coco also apparently rises in pH when it dries, which is why you should water to 10% or so runoff.

I used to grow in soil, and coco is def a different beast. Live and learn! Keep me posted.