Go to Seed

More than once I have been asked about the expiration date on the back of seed packets and what it really means.

In the seed industry there is a six-month standard for germination testing. What that date on the back of your packet actually tells you is when that batch of seeds was last tested. For example, in the photo below it says 12/08. This means those seeds were tested for germination in 6/08 and had a high enough rate of germination to continue selling them. I believe this percentage must be somewhere around 94% rate. There are discount seed companies that offer seeds at a lower price, but generally the trade-off is a lower rate of successful germination - around 55-65%. Keep that in mind.

What I believe to be the most important factor in seed success is how they are stored. Seeds should be kept dry and cool. This could be in the fridge or a basement. They must be kept dry or they will rot. I have stored my seeds in their original paper packets, small metal containers and baggies. As long as they are cool and dry, they should be okay. In these conditions most will last well beyond their expiration dates. In general, vegetable seeds last longer than flower seeds. Below is a general guideline to follow, but loosely.

General viability guidelines:
beans - 3 years
beets - 2 years
carrots - 3 years
corn - 2 years
cucumbers - 5 years
lettuce - 3 years
peas - 3 years
peppers - 2 years
pumpkins - 4 years
radishes - 5 years
spinach - 5 years
tomato - 4 years
watermelon - 4 years

Remember these are just guidelines and if you take the time to store your seeds correctly you can expect a much longer length of time. I have used seeds with pretty old dates on them and they have still done well.

There are a few exceptions to this rule. Delphiniums seeds have a very low rate of success after one year. Also parsley should be planted according to the expiration date for best results.

 
If you're unsure, you can test your seeds. Simply space several out on a few layers of moist paper towels, roll up so that the seeds don't touch, and enclose the bundle in plastic wrap so it doesn't dry out. Place in a warm bright location (65 to 70 degrees is fine) but away from direct sun. Check the seeds every couple of days. If they haven't germinated — or only a few have sprouted — in a couple of weeks, chances are they're no good. If you prefer just throwing caution to the winds and not testing the seeds, be sure to sow more heavily to make up for lower germination rates.

Have fun planting!

Ciao!