Trouble growing seedlings of acid loving plants
I posted this to the seed growing forum, but haven't gotten any feedback.
The last two years I have tried to grow sourwood (Oxydendrum arboreum) and wintergreen (Gaultheria procumbens) from seed. Plenty of the seeds germinate, but they don't progress past the cotyledon stage. I kept a couple wintergreen seedlings alive for 6 months, and they never got true leaves.
I've been able to grow a wide variety of plants from seed, only these two have given me problems. I'm guessing that it's not a coincidence that they are both acid loving plants from the family Ericaceae.
I've tried regular miracle grow potting mix as well as the 5-1-1 mix with half the usual amount of lime. That is, I used 1/2 Tbsp per gallon, hoping to keep it more acidic.
Any tips for growing these kinds of plants from seed?