Navy beans are a warm-weather, dry-bean crop from Central and South America. They are part of the large family of beans called Phaseolus vulgaris L. Navy beans grow best in loose, well-draining soil with a pH level between 6.5 and 7, according to Purdue University Alternative Crops Guide. Plant navy beans in the spring when the soil is above 60 degrees F, because beans will rot in cold, damp soil. Navy beans need 105 warm days without frost to reach maturity.
Mix the soil at the planting site with two to three shovelfuls of rich, well-rotted compost for each plant. Turn over the soil with a garden fork until the compost is thoroughly mixed.
Make holes 1 to 2 inch deep in loose sandy-soil. For clay-like soil make holes 1/2 inch deep so that the bean is not prevented from sprouting by the heavy soil. Make the holes 2 to 4 inches apart in rows that are 24 to 36 inches apart.
Pat down the soil over the navy bean seeds with the flat of your hand. Water until the soil is damp all around the bean seed so it is stimulated to begin germination.
Water every few days to keep the soil damp. Approximately 1 inch of water per week for each plant will keep it moist, but not saturated. Water in the early morning or late in the evening whenever possible.
Keep the area around the navy bean plants free of weeds, it is best to pull weeds by hand to avoid damaging the shallow root system of the beans. After the beans have sprouted, spread a 1- to 2-inch layer of organic mulch around the young plants to keep moisture close to the soil and cut back on weeds.
Harvest the navy beans when most of the pods are yellow, with a few beginning to turn brown. Unlike snap or green beans, navy beans need to dry on the vine before harvest.
Cut the plant stalks and vegetation down to the ground after the harvest is complete. The plant matter will decompose on the soil and add nutrients for next year's crop.