If you are harvesting dry seeds you can winnow them in the wind or with a fan over either a bucket or tarp continuing until your seed is clean of plant debris.  For wet seeds you can run water through your mixture of plant/fruit and seeds and decant your seed as most plant debris will float off with water and viable seeds will sink.  However, when you make a mash for tomatoes and the fruit and seeds are all together, the seeds will float.  By putting your mash in a large container you can run enough water into the fruit and seed mixture to lower it specific gravity of the solution so the seed will sink.  Science is everywhere around you on the farm!  Clean, wet seeds are then poured out on to screens to dry in a well ventilated, dry, dark space like a barn or shed.  Sunlight and heat for too long will kill your seed and rob it of all vigor. 

Timing is always a factor in saving quality seed.  Nature isn’t dependable so you have to act quickly when your crop looks completely finished.  Some crops are a bit easier like pumpkins or squash which can wait until later in the season to be processed (but even then they have their limited window of optimum processing time).  Be sure to process crops when they want you to by keeping an eye out when they’re ripening and watch the weather.  I’ve tried to harvest an acre of wheat by hand in the course of a week.  Well, that week was about half sunny and half rainy and the wheat had started to lodge and I was losing my window.  The perfect looking crop had gone from erect, tall, dry wheat to lodging and falling on top of itself from rain and weakening due to becoming over-mature.  Fruited crops (or wet-seed crops) do best in humid and rainy climates like the northeast and give you a bit more of a window to harvest them.  Still, pay attention because if they go beyond ripe and mold or grow fungus you’d be better off not saving them for seed.  You have the best luck with full ripe but not rotten. 

I'm happy to do the work that I do and work hard to preserve seed diversity and promote seed saving.  With a focus on tradition and good growing practices, we all can build up and preserve our soils, our communities, our heritage, and our seed diversity.  Groundswell Seed Farm is here to help you grow your own food as well as inspire you to grow seeds, too.