Propagation: Coconut coir stunted growth, yellow seedlings??, 0 by NisiNJ

NisiNJ wrote:
I decided to sow my seeds in coir this year because I had a problem with gnats last year. They came in via some invested seed starting mix. I know that most peat mixes are not pre-infested but had read that the gnats don't bother as much with coir.

The coir-sown seeds germinated fine but were in trouble as soon as true leaves appeared. The first true leaves were pale and many of the seedlings died. Here are some pics. These are all petunias.

First, a closeup of green cotedylons (I know that's misspelled) but pale true leaves.