When to Plant Beans
Beans germinate best when your soil temperature is at a consistent 60 to 70 degrees. You should always plant beans after your last frost date. Most beans can be planted all at once, because they will continue producing throughout the season. However, if you are growing bush snap beans, you may want to sow a few seeds every two to three weeks throughout the season to achieve a consistent harvest.
How to Plant Beans
Beans are not overly choosy about soil, but it is best to loosen the soil down to a depth of at least three inches and mix in some compost if possible. They prefer full sun to part shade. Beans, regardless of type, should be planted about one inch deep. Bush types should be spaced four inches apart, and pole types six inches apart.
You can grow pole beans several ways, as long as you make sure you give them plenty of support. Some of the most common ways to support pole beans are on trellises, bamboo "tipis," or merely by planting them along a chain link fence they can clamber onto. Another fun way to grow is to create a "Three Sisters" garden, in which you plant corn, which will support the pole beans, and squash, which will act as a living mulch and benefit from the nitrogen-fixing effects of the beans.
The key with beans is to provide them with steady moisture during peak production, as well as directly after planting. They do not need to be fertilized. They can be bothered by pests such as the Mexican bean beetle, which should be hand-picked and destroyed. Aphids can also make nuisances of themselves. Leaf spot and rust are other common issues with beans.
Snap beans are best harvested when they are tender, a few inches long and still fairly thin. They are much less stringy at this point. The best way to harvest them is to pull the bean off the vine while holding the vine with the other hand. Bean stalks tend to be rather brittle, and it's easy to break part of it off while harvesting your beans. You'll probably end up harvesting pole beans at least once a week; they are very prolific producers.
If you are growing dry beans, allow them to stay on the vine until the pods turn brown and, if shaken, you can hear the beans rattling inside. Shell the beans, and allow them to sit out at room temperature to finish drying out before you store them. They should be stored in airtight containers, out of direct light.
If you want to save seeds from your bean plants for next year, simply pick the largest, best-looking beans from your dry bean harvest (you can also do the same with snap beans---just allow the pods on one of your vines to turn brown, then harvest the beans inside), label them, and store them in a cool, dark place until next year.