When saving seed, leave seed in the original packets or labeled envelopes and place them in an airtight container, such as a wide-mouthed jar. For long-term storage, securely wrap 2 tablespoons of powdered milk in tissue paper and place it in the bottom of the jar. The powdered milk acts as a desiccant and lengthens storage life of garden seed. Keep the jar in the refrigerator until next gardening season.