For two years I picked wild cranberries in October in the mountainous forests and extracted their seeds. I plant them in a mixture of peats and sawdusts, and put them at around 15 degree Celsius with 8 hour sunshine per day.
These seeds usually sprout in about 4~6 weeks. Total sprout rate was around 50%. In week 5~8, cotyledons will appear and span. Some mold will appear at the same time, mostly white thin-thread-mold, and rarely some dark green dot-mold. Then the seedling always stopped growing any more and die. About 1/3 of them grew out a pair or true leaves, and the others just die with only cotyledons. The seedlings are always very weak, less than total length of 1.5~2cm and root length 1~1.2cm.
I have grown domesticated commercial cranberries successfully from seeds before, with same equipment, peat, condition and even same mold appeared. But the wild ones just seem not surviving past seedling period. Their parent berry vines in wild forests are very healthy and fruitful, and I didn't see any sickness on them. What could the problem be?
I assume my wild cranberries are of Vaccinium oxycoccos (or V. vitis idaea?) species, with very small reddish blueberry-like fruit diameter 8mm, but I am no botanist, not sure about this.
