How to Grow and Care for a Beanstalk Plant

The plant most associated with the magic beanstalk story is the Scarlet Runner Bean, or Phaseolus coccineus. Native to the mountains of Central America, this species is a fast-growing, climbing vine prized for both its ornamental and edible qualities. The vines easily reach heights of 10 feet or more in a single season, producing heart-shaped leaves and brilliant scarlet-red flowers that are a significant attraction for hummingbirds and bees.

Planting Beanstalk Plant Seeds

Plant seeds directly in the garden after all danger of frost has passed and the soil has warmed. This species performs best in fertile, well-drained loams rich with organic matter and a soil pH between 6.0 and 7.0. Heavy or persistently wet soils should be avoided, as this can cause seeds to rot.

For an earlier start, plant seeds indoors four to six weeks before the last anticipated frost; soaking them overnight can aid germination. Plant the large seeds one to two inches deep and four to six inches apart at the base of their climbing structure. Germination occurs within 7 to 14 days. If starting indoors, use biodegradable pots to minimize root disturbance during transplanting.

Caring for Your Beanstalk Plant

These plants thrive in full sun, requiring at least six to eight hours of direct sunlight each day. Consistent sunlight fuels their rapid growth and ensures the development of a dense, leafy vine and a profusion of red blossoms.

As a climbing vine, the Scarlet Runner Bean requires a support structure. The twining vines can grow up to 15 feet long and need a sturdy trellis, fence, or poles arranged in a teepee to ascend. Install this support at the time of planting to avoid damaging the root system later.

Consistent moisture is important throughout the growing season, especially as the plant begins to flower and produce pods. Provide about one inch of water per week, ensuring the soil remains moist but not waterlogged. Applying a layer of organic mulch around the base of the plants helps conserve soil moisture and suppress weeds.

As a member of the legume family, the Scarlet Runner Bean has a symbiotic relationship with soil bacteria that allows it to fix atmospheric nitrogen. In soil rich with organic compost, additional fertilizer is not needed. If your soil is less fertile, a fertilizer low in nitrogen but higher in phosphorus and potassium can be applied at planting to encourage root growth and flowering.

Harvesting the Beans

The beans can be picked at two different stages. For use as a fresh green bean, harvest the pods when they are young and slender, typically around three to five inches long. The pods are tender and can be cooked similarly to common green beans. Regular picking of these young pods encourages the plant to produce more flowers and beans.

If you prefer dried beans, allow the pods to mature and dry completely on the vine. They will turn brown and brittle, and the seeds inside will become hard. Once fully dry, shell the pods and store the large, beautifully mottled seeds in an airtight container for use in soups and other dishes. These dried beans require soaking before being cooked.

Beyond the beans, the vibrant flowers are also edible. They have a mild, bean-like flavor and can be added raw to salads for a splash of color and a unique taste.

Common Beanstalk Plant Problems

Aphids are small, sap-sucking insects that can congregate on the tender new growth and flower clusters. A strong spray of water from a hose is enough to dislodge them from the plant.

Powdery mildew is a fungal disease that appears as white, dusty patches on the leaves, particularly in humid weather with poor airflow. Good air circulation from a support structure helps prevent this. Watering at the base of the plant rather than overhead also helps keep the leaves dry and less susceptible to fungal growth.