Harvesting seeds from your vegetable garden is one way to obtain seeds for next year's crops. If you want the fruits or vegetables to resemble the parent plant, avoid harvesting seeds from hybrid varieties. Seeds taken from hybrid varieties produce plants with inconsistent characteristics. When harvesting eggplant for culinary purposes the seeds are underdeveloped. To use the fruit's seeds for next year's crop, it will need to be left on the vine long after you would normally pick its fruit.
Select the individual eggplants to use for seed harvesting. When using eggplant for culinary purposes, it is best harvested when 6 to 8 inches long. If you have any fruit that have already surpassed 8 inches in length, use those first for seeds.
Cut the eggplant fruit from the vine when the fruit is hard and dull in color.
Slice the eggplant in half and use your hands to separate the seeds from the fleshy area of the fruit.
Spread the seeds on a paper towel and allow them to dry out at room temperature.
Fill a small cloth bag with ½ cup of dried powdered milk and tie the bag shut.
Place the cloth bag in the bottom of the glass jar.
Put the seeds in the jar, on top of the bag. The bag of powdered milk will help keep the seeds dry.
Seal the jar with a lid to keep airtight while storing. Store in the refrigerator and do not open the jar until you are ready to plant.