Bean seeds generally last for at least three years if they are stored in a cool, dry location. However, planting seeds haphazardly in hopes they grow is a waste of valuable gardening time. If you aren't sure about the quality of saved bean seeds, germinating a few of the seeds in a clear plastic bag will help you estimate what percentage of the beans are viable and worth planting.

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Step 1

Moisten a paper towel. Squeeze the paper towel so it is damp but not dripping. The beans will rot in too much moisture.

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Step 2

Lay the damp paper towel on a flat surface. Count several beans and place them on the towel, equally spaced. A number such as 10 simplifies the mathematical calculation. Discard beans that are cracked or shriveled; damaged beans will skew the results.

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Step 3

Place another moist paper towel on top of the first towel so the beans are between the two layers.

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Step 4

Roll the paper towel carefully and place it in a resealable plastic bag.

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Step 5

Mark the date on the outside of the bag. Place the bag in a warm location away from direct heat or bright sunlight; bean seeds don't require sunlight to germinate.

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Step 6

Remove the paper towel from the plastic bag after three to five days. Unroll the towel carefully and count the beans with sprouts at least 1 1/2 inch and at least one strong root. Bean seeds with shorter sprouts have a slower germination time and are probably not viable.

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Step 7

Determine the rate of germination. For example, if five of 10 seeds germinate, you can reasonably expect that 50 percent of your saved beans are viable.