The question is how long seeds last before they die. Seeds are living things and they last only a year while others manage four to five years.
For longer life expectancy they need to be kept in ideal conditions. Best place to store seeds are refrigeration, dark, cool or dry places.
Seeds that Last 1 Year
Many seeds last only one year before their viability disseminate. Seeds that last a year are Parsley, Shallots and Leeks. Others include sweet corn, onion seeds and chives.
• Sweet corn
• Onion seeds
Seeds that Last 4 to 5 Years
There are many seeds that last 4 to 6 years in the right conditions. Common seeds that last 4 years are squash and cucumbers. Others include brassicas, tomatoes, and melon seed.
• Melon seed
How to Determine the Viability of a Seed
The only way to determine the viability of a seed is to test it. You can plant about 10 seeds in a pot or place in a plastic bag with soil. Make sure the flowering pot has adequate sun, water.
You need to know the normal time it sprouts. Once the time is reached count the number of sprouts. If you sow ten seeds and five sprouts then the viability of the seeds are 50%.
Storage Requirements for Seeds
There are a few ways to prolong the viability of seeds. Some seeds are best kept in refrigeration why others require a dry place. the place should be dark and devoid of any light. it should be cool and well aerated.