Originally Posted by Bluemater
Only happened to two seedlings in a batch of Canna Terra Pro diluted with 50% perlite.. Since transplanting few days ago they have not improved..
What are you feeding them?
They look like something of a trainwreck. They're growing, they're not getting enough nutrients, and there is light/heat damage (partial chlorosis of one leaf), probably because they're not getting enough nutrients.
The media you've mentioned - perlite, coco coir and canna terra pro have very little nutrients in them.
Also, it's always good to add a couple of tablespoons per 2 gallons of soil of magnesium lime to the mix, and let it rest for a week or longer. It will raise and buffer the pH and supply calcium for cell growth and magnesium for chlorophyl production. Chlorophyl is what makes plants green, and helps with phototropism.
With both coco coir and soil mixes like canna terra pro, it is always best to soak them in water for at least a couple of days. That way the medium isn't drier than the roots, which can lead to symptoms of nutrient deficiency/lockout.