Slow and Pale Seedlings

Hi Guys, First-time grower here. I hope someone can recognise what's happening to my seedlings.

• They've been growing for nearly 2 weeks and I think they are a bit slow.
  
• There is definitely some colouration problem, with the veins of the leafs appearing darker than the majority of the leaf surface.

The stretch occurred on the first couple of days, and has been stable since (I lowered the light to within a couple of inches of the tops).
Here are my details:
Indoor grow, BBxWW from Female Seeds
Seeds went straight int the pots that you see in the pics.
Humidity dome and under-pot heat pad.
Flourescent,2-bar grow-light with Sylvania Grow-Lux 18W tubes.
Decent-quality 'seed-raising' mix and I haven't used any added nutrients yet.
I think that the pots are too big and I haven't been patient enough to allow them to dry-out sufficiently between waterings. What's your opinion?

Here's another pic that shows the stretch and pot size:

No aeration in that pot. Too packed. Moisture problems, no oxigen for gas exchange.
- fix the problem and many deficiencies will go away...
Overwatering & underwatering
High humidity
Uneven moisture levels in the soil or growing medium
Too-high levels of N-P-K nutrients
PH is too high or low

Tupapa said:

No aeration in that pot. Too packed. Moisture problems, no oxigen for gas exchange.
- fix the problem and many deficiencies will go away...
Overwatering & underwatering
High humidity
Uneven moisture levels in the soil or growing medium
Too-high levels of N-P-K nutrients
PH is too high or low

Click to expand...

Thanks for that. It matches my own suspicion.
I've flipped a couple of the pots upside-down and lifted the pot for a look, and I can see that the roots have reached the sides and bottom of the pot in each case.
I've let the pots dry right out now, and I'm just watering with tiny amounts now, every couple of days.
Any other ideas regarding how I should go about fixing an aeration problem?

Repot that., Mix a bach of soil 70% soil 30% perlite and bury the stem all the way up to the cotyledon leaves..

Tupapa said:

Repot that., Mix a bach of soil 70% soil 30% perlite and bury the stem all the way up to the cotyledon leaves..

Click to expand...

Good call. I've also ditched the humidity dome, which will mean that the whole moisture cycle will speed up and, hopefully, I'll get more control.
Thanks

Mullumbimby said:

Thanks for that. It matches my own suspicion.
I've flipped a couple of the pots upside-down and lifted the pot for a look, and I can see that the roots have reached the sides and bottom of the pot in each case.
I've let the pots dry right out now, and I'm just watering with tiny amounts now, every couple of days.
Any other ideas regarding how I should go about fixing an aeration problem?

Click to expand...

Also u need to monitor ur ph., U need to get a ph pen off ebay. Cannabis best ph for plants uptake of nutrients is between 6-7

Tupapa said:

Also u need to monitor ur ph., U need to get a ph pen off ebay. Cannabis best ph for plants uptake of nutrients is between 6-7

Click to expand...

You are the MAN.
Did exactly what you said and it worked like a charm
My plants are fairly roaring along now.
Gotta love RIU. Learning so fast.