Saving your own heirloom green bean seed is so easy! And it’s a great way to save on organic seeds for your vegetable garden next year.
I found a really lovely green bean that is our favorite. We’ve grown Blue Lake FM-1 pole beans for several years and love the flavor & production. Pole beans work really well for me no matter what stage of motherhood I’m since there is very little bending involved when harvesting pole beans. This variety seems to start producing a little later than other gardeners in my area, but I guess the same could be said for a lot of the things our garden produces. I play it safe and never try to plant before our last frost date. (Which was quite the temptation this year since it was so dry this spring.) Once the beans start bearing they continue all the way until the first frost, though I stopped harvesting two weeks early, around 10/1 for Zone 5, because the pods were getting tough even though the beans were small.
One of the things I appreciate about pole beans is that there are always some beans you miss during the harvest. I don’t even need to really plan for saving heirloom been seed because there are inevitably plenty of dried bean pods when the foliage dies back.
How to Save Heirloom Green Bean Seed
Good news! Beans are generally self-pollinating! Usually pollinated by wind, but occasionally by bees & other insects. A lot depends on your circumstances, your bee population, etc.. but generally you shouldn’t have to worry about cross-pollination. If cross-pollination does occur, you won’t be able to tell by looking at the seed so just make sure you keep the years separate and don’t mix them up in case it turns out that one year the wrong beans grew! If you’re concerned about cross-pollination, cover the plant for bush varieties or don’t grow 2 different varieties side by side. Generally, I’m not concerned about beans cross pollinating.
Collect seeds from your best tasting & most productive plants. If you like the traits of a particular plant, you’ll want those to show up next year.
Leave the beans to dry on the plant. If adverse weather conditions threaten your seed harvest, you can pull the plants with the green pods out by the roots and hang them upside down in a warm, dry location until they are ready for harvest.
When the seed pods are fully dry and a good shaking produces a rattling sound, you know they’re ready. This is a great job for kids. Gather them around and have them help you pop out the seeds. They love to help! It’s like opening a present!
To check if they’re fully dry, pound them with a hammer. If they shatter, you’re good to go. If they simply get smashed, they need to dry longer.
Not all of your bean seed will be good. You can tell pretty easily by looking at them. If they’re large, plump, and uniform in size, they’re good. If they discolored, moldy, shriveled, or broken discard them.
Store your dry seeds in an airtight bag or container in the freezer. Not only will this prevent insect damage, but it will maintain seed viability, and prevent the conditions that could destroy the seed (like moisture.)
Beans maintain a pretty high germination rate. 70% is the average, and even in right conditions, it will only reduce to 50% over 4 years. To test for germination wrap a sampling of 10 beans in a wet paper towel, place them in a plastic zip bag and set them in a warm place for a week to 10 days. By then they should have germinated. Count out how many were good and there is your germination rate. It’s a good idea to do this a month or so before sowing season. That way you’ll have a chance to buy seed if you think you’ll need to.