I generally do very well with germination, technique wise I sand the seeds, then paper towel, then into rapid roots and this is normally good for 11/11 on a pack.
I recently popped 16 seeds and kind of dropped the ball, I didn’t have a heat mat or anywhere consistently warm so they ended up on top of the grow tent where they dropped to 13c~ every night.
I didn’t have any rapid roots either so they ended up in pots of coco in a cold window.
A week later and 4 of them haven’t pushed anything up through the coco. I gently dig down and find the root had turned to mush in the middle and breaks apart into two.
One of the seeds is still in the paper towel at this point having never cracked, I tried popping in my mouth, having read about it on here and end up dropping it on the carpet and unable to find it.
At this point it was looking like I wasn’t going to get the 8 female plants I wanted to run, so I tried my luck at resurrecting some of these damped off seedlings.
To my amazement I got 3/4 and a week later found the seed on the floor which when put in a cup of 1% h2o2 sprouted as well 2nd time round.
I bought a heat mat and some rapid roots, split them in half with the seed on the surface and the remainder of the root pointing down then sprayed them daily with 1% h2o2 and seedling fertiliser as directed on the bottle.
Here are the results, these plants are all over 5 weeks old when photographed 
This one did almost nothing for a month, I pulled the shell off and the cotyledon slowly died back for weeks before eventually the first set started growing. It was the most damage seed with 90% of the root breaking off leaving only 1/4" or so.
This is the one that survived drying out on the carpet for a week before being found, looks like it self topped with no node to continue growth so not viable but I found it interesting regardless.
This one also self topped but is healthy.
This one the root didn’t actually break apart, when I dug it up it was still firm but hadn’t grown any further and was starting to go translucent, the tip of the root was also black. Seemed to be in stasis for a few weeks after but then started slowly growing.
h2o2 is the business. If you have seedlings that damp off or even go mushy before breaking the surface it is possible to save them.
