Jack Herer, small leaves and yellowing?

Hello,
Im new here and I just have some questions.
I am doing some Jack Herer, HashPlant, and BlueBerry.
The Jack Herer are giving me a problem. They are from Sensi. Well they are all about 2 1/2 weeks old. In 2 gallon pots to start with. With Peat Gravel in the bottom for drainage. The Soil is a mixture of hyponex from Walmart and some potting soil, and other types of soil from Steins Gardens and Gifts.
I have just a touch of manure in there as well as plenty of peat moss.
Well the BlueBerry and Hash plants are doing alright. They are starting to enlarge like they do after 1-2 weeks. But the Jack Herer are getting worse and worse...
The stems are a little on the thin side and the leaves are still pretty small and starting to yellow a bit. And now they are starting to lag farther and farther behind. I beleive that they are not liking the soil as I heard they are picky on their soil.
Can anyone tell me what they think?

Pics would help.

Otherwise...a guess a good flush wouldn't hurt. Maybe the soil is a bit hot...but I think they would of showed this problem before now.

If a good flush doesn't seem to fix it...then I suggest 1/4 strength of a well rounded nute like 20-20-20

Drink!

Father Jack,
So whats the scoop on Jack Herer from Sensi?
Do they require more ferts than normal? Or Less?
Im confused cause Ive read BOTH.
I tend to believe that they are highly sensitive to nutes but I have never done Jacks before.
I just want to know the general rule on the Jack Herer. Would they NOT like extra Peat Moss?
Wouldnt ya know, Havent used my camera in 6 month s and now I cant find it...

I find JH is nute sensitive. I can't feed it as much as I give strains like G13 and NL. Peat can cause problems with any strain if the ph starts to drop from the peat breaking down. Do you have any lime in the mix?

Cheers,
SC