Growing artichokes (Cynara scolymus) in Missouri’s Zone 6b-7a can be challenging due to its colder winters, but with the right techniques and care, you can successfully grow them as an annual or perennial in a protected environment. Here’s a comprehensive guide for growing artichokes in Missouri:
1. Choose the Right Variety
- Variety Selection: Artichokes are typically grown as perennials in warmer climates, but in Missouri, due to the cold winters, they are often grown as annuals or require winter protection. Choose cold-hardy varieties if attempting to grow them as perennials.
- ‘Green Globe’: The most popular variety for gardeners, it produces large, globe-shaped artichokes. It’s relatively hardy and works well for annual planting.
- ‘Imperial Star’: A variety that’s suited for growing as an annual in cooler climates. It produces large, high-quality buds and is quicker to mature than other varieties.
- ‘Violet de Provence’: A French variety with a purple hue, often used for culinary purposes. It has a delicate flavor and works well in milder climates but can be grown as an annual in Zone 6b-7a.
- Annual vs. Perennial: While artichokes are typically perennials in USDA zones 8-10, you can grow them as annuals in Zone 6b-7a or grow them in pots and bring them indoors during the winter.
2. Planting Time
- Indoor Starting: If growing artichokes as annuals, start seeds indoors 8–12 weeks before the last frost (late February to early March in Missouri). Starting seeds indoors gives the plants a head start.
- Transplanting: Transplant seedlings outdoors after the last frost, typically in late April to early May when the soil has warmed to at least 50°F. In Missouri, artichokes need a long growing season, so it’s crucial to start early.
- Frost Sensitivity: Artichokes are highly frost-sensitive, so it’s best to plant after all danger of frost has passed. For perennial varieties, you’ll need to protect them during the winter months.
3. Site Preparation
- Soil Requirements: Artichokes prefer well-drained, rich, fertile soil with a pH of 6.5 to 7.0. Since they are heavy feeders, incorporating plenty of organic matter like compost or well-rotted manure into the soil before planting will improve drainage and nutrition.
- Soil Depth: Artichokes have deep root systems and need at least 12 inches of soil depth to grow well.
- Location: Choose a full-sun location that gets at least 6–8 hours of direct sunlight per day. Artichokes need a lot of sun to develop large, healthy buds.
- Spacing: Space plants 3–4 feet apart to allow for proper growth and air circulation. Artichokes are large plants, and they need plenty of space to thrive.
4. Planting
- Direct Seeding or Transplanting: Artichokes can be started from seeds or young transplants. Transplant seedlings into the garden after the threat of frost has passed. If starting from seed, plant them about 1/4 inch deep in pots and transplant them after the seedlings have developed several leaves.
- Planting Depth: When transplanting seedlings, plant them at the same depth they were in the pots. Ensure the root ball is not buried too deep to avoid rot.
- Watering: Water immediately after planting and continue to keep the soil moist but not soggy. Artichokes need consistent moisture, especially during the early stages of growth.
5. Watering and Maintenance
- Watering Needs: Artichokes are water-hungry plants. Ensure they receive 1–2 inches of water per week through either rainfall or irrigation. They prefer moist, well-drained soil but are susceptible to root rot if the soil is too wet.
- Watering Method: Use drip irrigation or soaker hoses to water the base of the plants and avoid wetting the foliage. This helps prevent fungal diseases.
- Fertilization: Artichokes are heavy feeders. In the spring, apply a balanced fertilizer with a higher ratio of phosphorus and potassium to promote root and flower development. After the first harvest, apply a nitrogen-rich fertilizer to encourage new growth.
- Weeding: Keep the area around artichokes free of weeds. Mulching with straw or grass clippings will help suppress weeds and conserve moisture.
- Pruning: Remove any dead or damaged leaves to promote healthy growth and airflow. Also, remove flower buds early in the season if you’re growing artichokes for larger buds.
6. Growth and Bud Formation
- Initial Growth: Artichokes grow in a rosette pattern with large, silvery-green leaves. As the plants mature, they develop tall flower stalks.
- Flowering: Artichokes are grown for their edible buds, which are the flower buds before they bloom. The buds will develop in the second year if you’re growing them as perennials. For annuals, you’ll see buds form in mid-to-late summer.
- Harvesting Buds: Artichokes are harvested before the buds bloom, when they are tight, firm, and fleshy. Once the bud starts to open and flowers begin to show, it is no longer suitable for eating.
7. Pest and Disease Management
- Common Pests:
- Aphids: Aphids can damage artichoke plants, especially during the early growing stages. Use insecticidal soap or neem oil to control aphid populations.
- Slugs and Snails: These pests can feed on artichoke leaves. Use beer traps or diatomaceous earth to deter them.
- Artichoke Plume Moth: This pest lays eggs on the plants and can cause damage. Regularly inspect plants and remove any damaged parts.
- Diseases:
- Downy Mildew: This fungal disease thrives in humid conditions. Improve air circulation around the plants, avoid overhead watering, and remove infected leaves.
- Rust: Artichokes can be susceptible to rust, which causes orange spots on the leaves. Remove affected leaves and treat with fungicides if necessary.
- Fusarium Wilt: This soil-borne disease causes wilting and yellowing of leaves. Use disease-resistant varieties and practice crop rotation to prevent it.
- Powdery Mildew: Another fungal infection that causes a white powdery coating on leaves. Increase air circulation and treat with appropriate fungicides.
8. Harvesting
- Timing: Harvest artichokes when the buds are still tightly closed and before the scales start to separate. This typically occurs in late summer to early fall, around July through September in Missouri.
- How to Harvest: Use a sharp knife or pruners to cut the bud from the plant, leaving about 1-2 inches of stemattached. Harvest buds when they are large, firm, and dark green (or purple, depending on the variety).
- Multiple Harvests: In some varieties, you can get multiple harvests from the same plant. After the main buds are harvested, smaller secondary buds may develop.
9. Storage
- Fresh Use: Fresh artichokes can be stored in the refrigerator for up to 1–2 weeks. To keep them fresh, place them in a perforated plastic bag or wrap them in a damp paper towel and store them in the crisper drawer.
- Freezing: To store artichokes long-term, they can be blanched and frozen. To blanch, steam or boil the buds for 3-4 minutes, cool quickly in ice water, and then freeze.
- Drying: While artichokes are usually eaten fresh, some gardeners choose to preserve them by dehydrating. However, drying diminishes their texture and flavor, making them less desirable for many cooks.
10. Considerations for Missouri’s Climate
- Cold Tolerance: Artichokes are hardy to USDA zones 7-10, so they may not survive the cold Missouri winters (Zone 6b-7a) without special care. If growing them as perennials, it’s essential to mulch heavily in the winter and provide protection like row covers or even a cold frame.
- Summer Heat: Missouri’s hot summers can benefit artichokes, as they thrive in warm temperatures. However, if temperatures exceed 90°F regularly, you may need to provide some shade during the hottest part of the day.
11. Challenges
- Cold Winters: Missouri’s cold winters make growing artichokes as perennials challenging. You will likely need to treat them as annuals or provide them with extra protection through the winter.
- Frost Sensitivity: Artichokes are particularly sensitive to frost, and frost damage can significantly affect your crop. Be sure to plant them after the last frost in spring and protect them before the first frost in fall.
- Slow Growth: Artichokes require a long growing season to reach maturity. In Missouri, it may take 2 years to see a good harvest if growing them as perennials. For annuals, expect a smaller yield in the first season.
By following these guidelines, you can enjoy growing artichokes in Missouri, either as an annual or with extra care as a perennial. Growing them may require some patience and attention to detail, but with the right techniques, you can produce a delicious and unique crop. Let me know if you need more information!
