My degree of success with peas in gutters indoors had been very variable, with less than 50% germination in one case. I have now followed a suggestion (can’t remember the source) of rolling a line of peas in a moist piece of kitchen roll, popping the roll into an unsealed plastic bag and leaving it in a warm place, such as an airing cupboard, for a few days. In one case sprouting was 50% over a couple of days so I put these in modules and did the rest over the next week by which time a few seads, but only a few, had turned to mush. Another pack of seeds gave almost 100% sprouting after a few days. It’s a bit more work in the short term but I think it’s well worth it. I suspect that at least part of my poor showing in gutters was compost which was too wet, but it is much easier to control moisture with this method.
Another advantage is knowing within a few days if you have viable seed or not. I wonder if you could try this with any seed to test viability?
John