Green beans are an annual that grow either as a bush or a vine. When growing green beans indoors, it is best to plant the bush bean variety as they are smaller and grow better in containers. Green beans require full sunlight so when keeping indoors in containers they should be placed in a sunroom or near a window that receives at least six hours of sunlight a day.
Step 1 - Preparing Soil
Green beans grow best in soil rich with organic matter. Buy compost-enriched soil, or work plenty of aged compost into garden soil. Green beans also need loose, well-draining soil sand as well. A good ratio is two parts garden soil, one part sand and one part aged compost.
Beans prefer soil with a pH level of 6.0 and 6.8. Avoid planting in soil that is rich in nitrogen. If you want to use a fertilizer, use a high-phosphorus fertilizer like a 10-20-10 and work into the soil two weeks before planting time. Aged compost will work just as well.
Step 2 - Preparing Containers
Green beans grow well in long and narrow containers because green beans often grow as vines, spreading out quickly. Make sure there are plenty of holes in the bottom of your container and line the bottom of the containers with a couple layers of newspaper so the soil doesn't ooze out of the holes.
Step 3 - Planting Seeds
If growing in containers indoors, plant in mid to late spring to make sure the plants will get plenty of sunlight. Plant seeds about four inches apart and 1 to 1 1/2 inches deep. If you are using eight-inch containers, plant one seed per container. Add one-foot stakes into the containers, pressing next to the planted seeds.
Step 4 - Caring for Green Bean Plants
Green beans grow best in temperatures between 50 and 85 degrees F. Soil temperatures should be kept between 60 and 85 degrees F. It is important that the soil is kept evenly moist, but not soggy. Water at root level. After seedlings have grown larger than a couple inches, mulch around them to preserve moisture. Continue to water lightly but evenly. Seeds will not germinate well in over-wet soil, so take special care not to over-water before growth occurs. Green beans are susceptible to diseases, including blight, anthracnose, and mosaic. Remove any diseased plants immediately because the disease can spread quickly.
Step 5 - Harvesting Green Beans
Bush beans should be ready to harvest only 50 to 60 days after planting. They are picked while still immature, when they are about three inches long and plumping out. Since green beans are an annual, eliminate the need to bend by pulling out the entire plant before picking off each bean. Then you can place the plant on a table while you pick the beans.