How to Grow Purple King Bean
Purple King Bean
Phaseolus vulgaris
vegetablePurple King Bean is a bush bean variety prized for its deep purple pods and excellent flavor. The plant produces abundant yields of tender, flavorful beans that can be eaten fresh as snap beans or dried for storage. These compact, determinate bushes are ideal for home gardeners seeking a prolific and attractive bean variety.
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Example Purple King Bean timeline · Pittsburgh, PA (Zone 6b)
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Plant Purple King Bean
Around Apr 17Near Pittsburgh's average last spring frost.
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Tend & protect
Late spring–summerWatering, feeding, and pest-watch reminders.
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Harvest Purple King Bean
Around Jun 6≈ 50 days after planting
Sample dates for Pittsburgh, PA. Sign up to get exact Purple King Bean dates for your own zip code.
Growing Conditions
Soil
Growing Zones
Find your zone →Thrives in zones 3-9; prefers warm-season growing in zones 5-8
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Germination
7-10 daysSeeds sprout and first leaves (cotyledons) emerge above soil. Seedling develops the first true leaves.
Keep soil warm (60-70°F minimum) and consistently moist. Do not transplant; direct sow for best results. Provide protection from cool nights if temperatures drop below 50°F.
Vegetative Growth
2-3 weeksBush develops multiple stems, more true leaves, and a dense, compact structure. Plant grows 12-18 inches tall.
Maintain consistent moisture. Mulch around plants to retain soil moisture and regulate temperature. Thin seedlings to proper spacing if direct seeded. Begin monitoring for pests.
Flowering
1-2 weeksSmall, delicate white or pale purple flowers appear along the stems. Flowers are self-fertile and typically appear in clusters.
Reduce watering slightly to encourage flowering and bean set. Avoid high nitrogen fertilizer which promotes foliage over flowers. Ensure adequate pollinator access.
Pod Development
2-3 weeksFlowers fade and purple pods begin forming and elongating. Pods quickly reach 4-6 inches long with visible bean shapes inside.
Continue consistent but moderate watering. Apply 2-3 inch layer of mulch. Monitor for pests and diseases. Begin harvesting snap beans when pods are young and tender.
Maturity
1-2 weeks (snap bean stage); 3-4 weeks (dry bean stage)Pods reach full size and may darken further in color. If left unharvested, pods will mature and beans inside will dry.
Harvest regularly to encourage continued pod production. If saving seed, leave pods on plant until fully dried and brown. Allow plants to naturally senesce at end of season.
Common Pests
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Hand-pick beetles and egg clusters. Use neem oil or insecticidal soap. Plant-wide removal of affected leaves. Row covers for young plants.
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Spray with strong water stream to dislodge. Apply neem oil or insecticidal soap. Increase humidity around plants. Ensure adequate water.
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Spray with water to remove. Use insecticidal soap or neem oil. Attract beneficial insects like ladybugs. Apply horticultural oil.
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Improve air circulation. Remove infected leaves. Apply sulfur dust or fungicide. Avoid overhead watering. Ensure proper spacing.
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Use disease-free seed. Remove infected plant material. Apply copper fungicide. Avoid overhead watering. Practice crop rotation.
Uses
Fresh snap beans
CulinaryPurple King Beans can be eaten fresh as snap beans when young and tender, offering a mild, slightly sweet flavor. Steam, sauté, stir-fry, or boil for side dishes; they complement both simple and complex recipes. [source]
Dried beans for storage
CulinaryAllow pods to fully mature and dry on the plant, then shell the beans for long-term storage. Dried beans can be soaked and cooked into soups, stews, and bean dishes that retain nutritional value. [source]
Nutritional content
CulinaryPurple King Beans are rich in protein, fiber, folate, and antioxidants including anthocyanins. They provide sustained energy and support digestive health as part of a balanced diet. [source]
Garden productivity
HouseholdAs a nitrogen-fixing legume, Purple King Beans enrich soil naturally by converting atmospheric nitrogen into plant-available forms. Incorporating spent plants into soil improves fertility for subsequent crops. [source]
Pollinator support
WildlifeThe abundant small flowers attract bees and other beneficial pollinators to the garden. Supporting these insects enhances overall garden ecosystem health and productivity. [source]
Harvest Tips
For snap beans, harvest pods when 4-6 inches long and still tender, typically 50-60 days after planting. Pick pods regularly to encourage continuous production throughout the season. Harvest in the morning when plants are dry. Grasp the stem near the pod while harvesting to avoid damaging the plant. For dry beans, allow pods to remain on plant until they brown and dry completely, usually in late summer; then shell and store in cool, dry conditions.
Fun Facts
- 🌱 Purple King Beans derive their striking deep purple color from anthocyanin pigments, the same antioxidants found in blueberries and acai berries, which fade to green when cooked due to pH changes in the pods.
- 🌱 Bush bean varieties like Purple King are determinate, meaning they grow to a fixed size and produce most of their crop within a 2-3 week window, making them ideal for succession planting to ensure continuous harvests throughout the season.
- 🌱 Beans belong to the Fabaceae family and form symbiotic relationships with root-nodule bacteria that fix atmospheric nitrogen, eliminating the need for added nitrogen fertilizer and actually improving soil health for the next crop.
Gardening Terms
New to gardening? Learn about terms used in this guide:
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