First coco grow - Very slow growth (photos)

Hi,

This is my 2nd ever grow. My first was in in soil under cfls and Im now using coco running a cob set up now which gives out a lot more light.

This is also my first ever auto grow and I have 3 sweet seeds cream caramel that sprouted on 25/12/16 (merry christmas one and all) and some cream manderin and colorado cookies autos which sprouted last Wednesday and have their first true leaves and are plodding along.

Im having an issue. Cream caramel takes approximately 65 days according to the diaries I have read. Im way behind them in terms of where the plants are at.

At first my temps were an issue, for the first 5 days the grow area was between 16 and 19°c. The light wasnt finished so was using LED bulbs. My cob fixture brought the temps up to between 21 and 24°c.

Still my wet dry cycle is taking a bit too long. They are only getting watered twice a week at the moment.

I am using the grow weed easy chart for coco and running gh nutes. My last feed i used a gallon of water and gave 1 tsp of micro, 1/2 tsp of grow and 1/4 tsp of bloom.

PH of my water was initially 7.2 until the last feed was PH adjusted to 6.4.

RH is 50% pretty constant.

I dont know if, because of my slightly low temps the lack of feeds is causing slow growth. The plants dont look particularly sick. Although one has retarded leaves.

These are coming up to 1 month old in 3 days time. They look yellower than they actually are due to the warm white cobs.
Heres the photos:





Thoughts?

Do you not have perilite mixed in? maybe the coco is compact too much and the roots need an airier medium?

I mix 50/50 or 60/40 perilite/coco

No just straight coco.

I did think about mixing but a lot of folks use it vanilla without any issues

Edit: I did take pains to not compact too tightly when i potted. I know watering does compact later

ph should be 5.8 for hydro/coco

Like you say, its likely the low temps giving them a bad start and the roots maybe trying to catch up. Never grow autos so I don't know how they behave. Maybe they will take off suddenly.
Just to reiterate the guy above, 5.5-6.5 ph but varying 5.8-6.2 allows all nutrients to be absorbed easier.

Ph its out of range for coco

Thanks for the input I will adjust down to 5.8 next feed and see how I go.

I have pretty much written these runts off but want to learn for the next batch that have popped.

The wet dry thing is a bit of a bitch to overcome as I am starting in the final pots.

I dont know how often to water the new seedlings.

When you stick your index finger in the coco down to the second knuckle if it feels dry water. Adjust PH too 5.8 - 5.6. Looks like you may wanna get some Cal Mag I see some yellowing. 1\4 strength nutes are a good starting point for seedlings up it from that point when you see slow growth...

5.8 minimum for coco, I like 6 personally, then if it drifts a little or your pen is off a tad it's still in range. How much are you giving them when you water? What size pots?