Often, when seeds fail to grow properly, home growers blame themselves. But some times, it is the fault of the seed producer.
The photo on the left is of a young plant with a genetic defect in photosynthesis. The plant on the right is affected by genetic dwarfism linked to rugose (wrinkled) leaves. Neither of these will make a viable crop, no matter how good the grower is. In a lot of out-crossing crops, inbreeding will increase the frequency of these kinds of deleterious alleles - and they are all too common (up to 20%!) in some of the cannabis seed lots we have grown out. The acceptable rate for such off-types depends on the severity of the problem, and the crop in question - usually less than 0.5% would be considered acceptable (but not great).
We have also seen issues with germination in some seed lots. This is why, for crops other than cannabis, federal and state seed laws require seeds to be tested (and frequently labeled) for germination before sale.
Healthy, fresh seeds require no special treatment to germinate successfully - cannabis seeds will emerge in 5 days even when planted 1"-2" into the soil, with good soil temperature and moisture. In our view, excessive manipulation of seeds (e.g. placing in damp paper towels to start germination) is not only unnecessary, it increases the risk of damaging the fragile sprouts during handling.
Once you have purchased seeds, how do you keep them healthy? They should be stored in a cool, dry place - a pantry shelf or drawer is fine. If the seeds are dry and in an airtight container, you can increase their life by refrigeration, but do not store seeds where they will be exposed to high humidity. Seeds can also be kept for very long periods in a freezer, but moisture conditions must be carefully controlled, and defrost cycles avoided.