Beans can be a staple crop of any garden. They are relatively fast-growing, with initial harvests occurring in as little as 50 days for some varieties, and they can be among the most productive vegetables if harvested often.
Beans come in different growth forms – bush beans that grow 12-18” tall and pole beans that climb to 6-8’ tall. They also have different types of harvest – for snap beans, you eat the pods in their entirety; for shelling beans, you eat the seeds inside; and for dry beans, you let the pods fully dry on the plant and then harvest the seeds for long-term storage.
Select an area with good drainage as the roots of bean plants do not like standing water. Consider hilling the soil if needed to improve drainage. Choose a full sun spot – aim for 8 hours of sunlight per day, but 6 hours is the minimum. Always direct-seed beans into your garden unless you need to shorten their time in the garden. Beans do not transplant well as their roots are delicate – sow and transplant them within paper pots if you must start them indoors.
In terms of timing, plant your beans outdoors only after all risk of frost has passed. Ideally, wait until the soil temperature is 15oC and the minimum air temperature exceeds 10oC. Consider planting your beans in waves, every two weeks, to spread out the harvest over a longer period. Plant the seeds 4-6” apart for bush bean varieties and 6-8” apart for pole bean varieties. Plant the bean seeds approximately ½” deep. Water the soil immediately after planting, and ensure the soil stays damp afterward to stimulate germination.
Keep the soil moist but never soaking wet – this can be done through frequent, low-volume watering or through the use of mulch to retain moisture.
Beans do not require much fertilization – their most important nutrient is nitrogen, which is primarily taken care of by symbiotic bacteria that convert nitrogen from the air into nitrates that are usable by bean plants. Despite having low nutrient requirements, bean plants still prefer soil that is high in organic matter. As the bean plants mature, a top-up of phosphorus and potassium will help improve your harvest. A “bloom formula” fertilizer is ideal in this instance.
If you plant pole beans, they need to be trellised. The bean plants are good climbers, so use a fence, lattice, twine, or conical stakes. Aim to trellis 6-8’ high, which gives you enough space to maximize growth while still allowing you room to see and reach the harvest.
Pests and Diseases
Rodents are usually the most challenging pest. Rabbits, mice, and voles will eat the seedlings when they are young – usually a week or two after they emerge from the ground – and eat the stem down to a nub, killing the plant. To protect your plants, install slightly-buried fencing or drape row cover over the newly planted area before the seedlings emerge.
Mexican bean beetles and Japanese beetles are other common pests. These pests each emerge in early summer and can be prevented by planting your beans in mid-May (if the weather allows) for harvest in early July or using diatomaceous earth or nematodes.
Clubroot is a common disease among beans that leads to inflamed roots and stunted growth. To avoid this, plant your beans in well-draining soil, use plants in the mint family as companions, and avoid planting in the same spot in your garden where legumes or brassicas were recently planted. If necessary, add lime to the soil to alkalinize it and bring it to a pH of close to 7.0.
Similarly, root rots (fusarium, pythium, etc.) are common diseases in bean plants. To avoid this, plant in well-draining soil and rotate legume crops. If you suspect that there may be root rot in the soil, plant the beans later in the season (e.g., at the beginning of August for an early-October harvest) as these diseases prefer hot summer conditions. Also, mound the soil before planting to improve drainage.
Finally, blight and powdery mildew are other common diseases. To prevent this, plant your beans early to avoid the primary blight season starting in mid-July, avoid planting too densely, and plant in an east-west orientation to maximize airflow if blight has been an issue before.
Most bush beans will begin to bear fruit in 50-60 days, while pole beans may take 60-70 days. It is very important to harvest the beans at least twice per week once they start producing, which will stimulate the plant to produce more beans. Harvest each bean when they’ve reached your preferred size.