Does Grass Seed Expire And How To Check

picture of grass seed

You’ve just noticed or had pointed out to you that your lawn is a little patchy. That’s okay you think, I’ve got an old box of grass seed in the garage, i’ll use that. But what if we told you that your grass seed may have expired? 

Imagine sprinkling that grass seed on your lawn only to find out that it doesn’t germinate. Luckily you’ve landed on this page, read on my friend and find out if you can still use that old bag of grass seed. 

Does grass seed have an expiry date?

Grass seed often has an expiration date stamped on the bag and can go bad over time. Its best to throw away any unused grass seed that is past the displayed date. As grass seed ages the percentage of seeds that will be able to germinate when sown decreases. This forces you to use more seed than normal to get adequate coverage and germination. You may also spend hours irrigating, feeding and nurturing seeds that will never produce grass.

How long can grass seed be stored for? 

As a rule of thumb grass seed lasts for 2 to 3 years, however seed less than one year old is best. There is some variation though between seed types, Rye grass seed for example stays viable for up to 5 years, significantly longer than other common varieties like Fescue grass seed and Bermuda grass seed.

How to store grass seed.

For best results to occur when sowing grass seed it’s important to know how to store it correctly. Best practice is to store seed in bags with mesh air vents. This allows air in while also preventing insects access. 

Perhaps the most important rule is to store the bag in a cool and dry place which is free of humidity. Ensure that you store it below 60 degrees Fahrenheit and with relative humidity of less than 60%. Cool is ideal but avoid at all costs freezing your seeds.

It is vital to keep insects and rodents away from grass seed when storing it and as above make sure the stored seed isn’t allowed to freeze. Another key point to consider is where to store your lawn seed.

Consider where you live and how cold it gets in winter, if it falls below freezing then a garden shed may not be the best idea. Instead consider using an insulated garage or basement. For absolute best results regardless of where you choose to store seed make sure you always purchase high quality grass seed.

Physical signs your grass seed may have expired.

It can be difficult to tell when grass seed has expired as there are often no obvious signs. Even the expiry date on boxes and bags are only a rough estimation and really do depend on storage conditions.

Sometimes though there are some obvious signs that you shouldn’t attempt to sow your lawn with your stored grass seed. Inspect your seed carefully for signs of fungi or discoloration, also look for damp or clumpy areas of seed. If you do find any of these conditions it is best to dispose of the seed and purchase a new batch. If you do use the seed then expect a low seed germination rate and patchy lawn area. 

Tips for sowing grass seed

It’s crucial to give your grass seed the best possible chance to germinate but old seed may need a little extra care and attention.

Make sure you water your seed twice daily to keep the top one inch of soil moist until germination occurs, once germination takes place, water every day. Once the grass growth reaches about 3 inches in height you can begin to mow the lawn as you normally would. Once the lawn has been mowed you can resume your normal watering schedule.

Make sure that your seeds don’t dry out and also don’t cover the seed with straw as it may contain unwanted seeds and weeds. Instead cover the seeds with a thin layer of topsoil. As we discussed before fresher seeds are always better when it comes to planting and germinating seeds.

Written by Jenny Harland

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