Beans are one of the easiest seeds to save. The seed is large. The plant does most of the work. You do not need a jar of fermenting pulp or a sieve. You need patience and a dry place to hang the plants.
This guide covers common beans, the bush and pole beans most Canadian gardens grow. Runner beans and fava beans behave differently, and the notes on crossing below explain why.
Pick the plants to save from
Mark two or three healthy plants in midsummer. Tie a strip of cloth around each one. Do not pick green beans from the marked plants. A bean plant needs to keep its pods to make mature seed.
Choose plants that grew well, set pods early, and stayed free of spots. Skip any plant with sunken brown marks on the pods or dark blotches on the leaves. Some bean diseases travel inside the seed and pass to the next crop.
Check the variety. Open-pollinated and heirloom beans grow into plants like the parent. Seed from a hybrid packet may not. Leave hybrid seed out of a swap.
Think about crossing
Common beans pollinate themselves, often before the flower even opens. Crossing between varieties is rare. A few feet between two varieties is enough for most home gardeners.
Runner beans are different. Bees carry pollen from flower to flower, so runner bean varieties cross easily with each other. Runner beans do not cross with common beans, since they are a different species. Fava beans also attract bees, and they cross with other favas. If you grow more than one runner or fava variety, write “possible cross” on the packet.
Let the pods dry on the plant
This is the main rule. Leave the pods on the plant until they turn tan or brown, feel papery, and rattle when you shake them. The beans inside are hard and full size.
In much of Canada, fall rain and frost arrive before the pods finish. Watch the forecast. If pods are yellowing but not dry and frost is coming, pull the whole plant out by the roots. Hang it upside down in a dry, airy spot, such as a porch, a garage with a window, or a spare room. Do not use a damp basement. The pods will keep drying and the beans will keep maturing for a couple of weeks.
If the weather stays dry, leave the plants standing. Pick pods as each one turns brittle. Wet weather on drying pods can cause mold or make the beans sprout inside the pod. Pick those early and dry them indoors.
Shell the beans
Open a dry pod with your fingers. The beans pop out. For a large harvest, put the pods in a pillowcase or a clean bucket and step on them, or rub them between your hands.
Sort the beans by hand. Throw out any that look shriveled, cracked, moldy, or spotted. Look for tiny round holes, which mean an insect has been inside. Discard those beans too. Keep beans that are firm, smooth, and the full color for the variety.
Finish drying the beans
A bean that came from a dry pod can still hold moisture inside. Spread the beans in a single layer on a plate or a screen. Keep them indoors, out of sun, for another one to two weeks. Stir them now and then.
A dry bean is hard. Press a fingernail into it. A dry bean does not dent. A damp bean does. Damp beans grow mold in storage, so keep drying if you are unsure. Seeds dried to a hard, brittle state last longer than seeds packed while soft. The tomato guide shows the same idea for wet seed in how to save tomato seeds by fermenting them.
Freeze the beans to stop insects
Bean weevils and other insects can lay eggs on beans that hatch in storage. Freezing kills them. Put the dry beans in a sealed freezer bag or jar and freeze them for a few days. Let the container warm to room temperature before you open it. Opening it cold lets moisture condense on the beans.
Store and pack the beans
Put the cooled beans in a paper envelope or a glass jar with a tight lid. Keep the container somewhere cool, dark, and dry. A closet shelf works better than a shed or garage, where temperatures swing.
For a swap packet, 10 to 15 beans is a fair amount. A beans plant gives a good harvest from only a few seeds, so another gardener can grow a short row and still have beans to save. Label each packet with the variety name, the year, and where it grew. Add whether the bean is a bush or pole type, since the next gardener needs to know if it needs a trellis. The full list of label details is in how to package and label seeds for a swap.
Write down anything you know about the bean. Maybe it matured early in a cool summer. Maybe it came from a neighbor, a parent, or a grandparent. That story often matters to the person who receives the packet.
Seed Swap and your bean seeds
Seed Swap does not have a swap list yet, and there is no way to post one yet. Both are coming. Beans you dry and pack this fall will keep until they arrive.