How To Grow Jalapenos From Fresh Seeds. If you sprouted seeds in a baggie, carefully cut the piece of towel with the pepper seedling. Grow your jalapeno peppers indoors and transplant them outdoors.
Canned peppers can last from 8 to 18 months, with pickled jalapeños lasting longer. Another key ingredient is light. Use a plant heat mat (amazon link) to keep the seeds warm so they can sprout.
Start your jalapenos seeds about 8 weeks before your last frost date.
Similarly, if you cut into a fresh jalapeño and notice that the seeds are already black, that too is a sign that it is inedible. Follow the seed packet for optimal planting depth. Drop one to three seeds in each container, then cover them with a light layer of mix. The seeds will also begin to brown and dry up.