Red kidney beans are classified as dry beans. They grow on an erect, bushy plant that typically reaches 18 to 24 inches in height. In most areas, you can plant kidney beans from seed after the last frost date for your area, usually in the middle of May. Red kidney beans grow best in 15-inch rows at a depth of 1 to 2 inches.
Select an area of your garden that receives full sun and has good drainage. One cup of organic fertilizer mixed in with each 10-foot row of soil provides a good start for your kidney beans. Drip irrigation or slow soaking the soil is the best way to water the kidney bean rows; you should avoid watering the seeds from overhead. It may take up to 16 days for the seeds to sprout, thin the rows at this point so that there are 3 inches between the strongest plants. Good circulation will help prevent disease.
You can stake the kidney bean bushes to help them grow straight, or leave them to flourish on their own. Red kidney beans grow best if you water the rows of bushes to the soaking point at least once each week, more if your area is experiencing drought conditions. You should also keep the weeds at bay, pulling them as needed. It's also a good idea to liberally sprinkle compost on the soil around the plants every other week, just before watering.
Tending the red kidney beans may also include pest control and treatments for fungus. If pesticides and fungicides are necessary, apply them as needed according to the manufacturer's directions. Consider an organic approach and plant aromatic herbs nearby as companions to your kidney beans. For example, rosemary will deter bean beetles and nasturtium will ward against whiteflies and aphids.
Kidney beans mature between 85 and 115 days after the seeds are sown. Once the red kidney beans mature, the bushes are cut off at the root and hung upside down in rows to dry. The beans can be harvested 10 to 15 days later by picking them from the bushes. Kidney beans contain lectin phytohaemagglutinin, which is a toxic compound that can severely upset your stomach if you eat them raw. Make sure that you boil fresh red kidney beans for at least 10 minutes before eating them.