we always put our nasturtium seeds on a paper towel and place them in a window for the winter. most make through to next year, some don't. we collect many of them to even our odds a tad. but I don't know if freshly collected seeds work in the same manner...? the ones we have collected and stored in the past always get potted or planted in "bad" soil. they always do better for us if the soil is in shall we say, rough conditions. sandy, with lots of pebbles, debris, and very little nutritional value. seems to be just fine. no use using expensive potting soil and fertilizers! cant speak for everyone, but its worked very well for us!
