Quote Originally Posted by cigarettes42
peat based soilless... Scotts premium

well if its soiless then your ph is way to high. but if its just the scotts premium dirt then i would say not enough aeration to the soil. are you feeding them every time you water?
Curious where you get your info? Been seeing this from different sources here lately. Please provide a link or two.

WIth peat based soil (often refered to as soilless - a link is below to better explain) the ingoing ph should be in the 6.3 to 6.8 range. (in the link below) Any lower and you are more likely to lock out nutrients. The higher end of the range allows you to have a bit of leeway as the buffers fade. Lowering your ph further is commiting suicide on the installment plan.

Soil Less Potting Mix?

From the article:
"Whatâ??s in a Soilless Potting Mix?
Most soilless mixes are predominantly sphagnum peat moss. Sphagnum peat is lightweight, inexpensive and in certain areas, renewable. Just as importantly, itâ??s well draining yet water retentive. Granted, until you get the peat thoroughly moistened, the particles can be very unpleasant to work with. Peat (alone) is also on the acidic side and most seed starting mixes have a soil pH around 5.8, which is fine for starting most seeds.
There are also amendments added to the peat, which can include:
"
and it goes on from there, but does fail to mention the buffers.

PH and Nutrient Uptake charts!