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How to Check if Sunflower Seeds Are Viable

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The low-maintenance sunflower (Helianthus annuus) grows all over the United States in USDA hardiness zones 2 through 11 (per the Old Farmer’s Almanac), making it a pretty common experience to have a handful of old sunflower seeds lying around the garden shed. Are those old sunflowers seeds ready to blossom into iconic bright-yellow annuals? While the jury’s still out on exactly how long you can store sunflower seeds, you don’t have to be a horticulturalist to perform an easy, lo-fi viability check.

Viability of Old Sunflower Seeds

You might think that knowing exactly how old those old sunflower seeds are will give you some insight about their viability, but it turns out that even the experts offer different answers on sunflower seed expiration dates. University researchers with Brazil’s Revista Ciencia Agronomica (or Agronomic Science) found that sunflower seeds remain viable for 12 months when stored in a cool, dry room, in a refrigerator or in a freezer. This remains true across just about all types of packaging too.

However, that doesn’t mean you’ll be left with rancid sunflower seeds after a year and a day. On the opposite end of the spectrum, the USDA Agricultural Research Service once tested common wild sunflower seeds that had been stored at room temperature in a jar for 20 years. Perhaps surprisingly, the scientists found that these hardy old sunflower seeds had a germination rate of 13 percent.

Perform a Viability Check

The first step on your journey to refresh stale sunflower seeds is to calculate the rate of germination. This basic viability check will give you an idea of how many of those old sunflower seeds will actually sprout when planted.

As instructed by Iowa State University Extension and Outreach, all you really need is some paper towels and plastic zip bags. Count your sunflower seeds – use at least 20, but more is even better – as you spread them onto several layers of paper towels moistened with water. Roll up the paper towels, ensuring that the seeds stay separated from each other, and then place the rolls in plastic bags, zip them up and store them in a warm area (about 70 to 80 degrees Fahrenheit).

Leave the seeds for about three days and then check them every day for a week. When a root pokes through the seed, that seed has germinated. After a week has passed, divide the number of seeds that have germinated by the number of total seeds tested to get a percentage indicating the potential rate of germination. If you’re careful, you can even plant the germinated seeds outdoors after the last spring frost, when soil temperatures are above 50 degrees.

Sunflower Seeds: Storage

Ideally, sunflower seeds should be stored in a cool, dry, indoor space rather than an outdoor environment. Storage methods such as paper or plastic bags, sealed glass jars and plastic bottles are all acceptable, with low to moderate humidity being immensely preferable. According to the USDA researchers who conducted the 20-year-old seed study, moisture content is a more critical factor than temperature. The combination of low humidity and a lack of extreme temperatures seems to have the biggest appreciable impact on sunflower seed longevity.

That’s not to say that temperature isn’t important, though. As a general rule, the lower the temperature of the storage area, the longer the life of the seed. In fact, the same USDA scientists estimate that for every five-degree drop in storage temperature, you effectively double the life expectancy of the sunflower seed. So, while growing sunflowers enjoy warm temperatures, to keep those old sunflower seeds viable for as long as possible, you have to help them keep their cool.

How to Check if Sunflower Seeds Are Viable. Sunflower (Helianthus annuus) seeds, whether purchased or saved from your own garden plants, lose viability the longer you store them. Age, storage conditions and temperature can all cause the seeds to expire before they sprout. Checking the seeds for viability before you …

Is it okay to eat expired sunflower seeds?

I just found a bag of sunflower seeds in my room and it says that it expired on December 5, 2009. Is it still okay to eat it?

9 Answers

i don

I ate expired sunflower seeds there’s nothing gross about it.

They tasted normal for me. I hope this is what ur looking for


Old Sunflower Seeds

I’d watch her carefully for a few days, and I’d definitely never let it happen again. While seeds aren’t great for guinea pigs, I’d be more concerned with contamination. It sounds like the seed you’re talking about came from a bird feeding area. Bird droppings can carry lots of nasty organisms that can make animals very sick (E. coli is just one example). You have no idea what kind of filth was on that seed.


Absolutely, try a couple of they tast odd then throw them out, expiration dates are a best guess when the food is not as fresh as it could be.. Since yo don;t have to refrigerate sunflower seeds they should be fine.


You could but I dont think that they will taste so good ! There nuts / seeds Honey

Leslie D

I did this last night with bad results. They tasted fine but made me pretty sick. Don’t do it.


when foods say it expired, its expired. only stuff like coffee doesn’t really expire


I wouldn’t because you may be at risk for food poisoning


dude ew. That is so gross! Like bye someore!

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I just found a bag of sunflower seeds in my room and it says that it expired on December 5, 2009. Is it still okay to eat it?