Grower’s Reference Guide: Turnip (Brassica rapa subsp. rapa)
Introduction
Turnips are a fast-growing root vegetable known for their versatility in the kitchen and ease of cultivation. Growing turnips organically enhances their flavor, ensures sustainability, and promotes soil health by avoiding synthetic chemicals. This guide provides everything you need to know about cultivating turnips using organic methods, from soil preparation to harvesting and storage.
Fun Fact:
Turnips have been cultivated for over 4,000 years and were once a staple food for ancient Romans and Greeks. In some cultures, they were even carved into lanterns before pumpkins became the Halloween norm!
Scientific Information
- Scientific Name: Brassica rapa subsp. rapa
- Key Characteristics: Round or elongated root with smooth skin, available in white, purple, or yellow. Green leafy tops are also edible.
- Common Uses: Culinary (roots and greens), animal fodder, and soil improvement through cover cropping.
Growth Overview
- Annual or Perennial?: Biennial (typically grown as an annual)
- Growth Form: Root vegetable with edible leafy tops
- Toxicity: Non-toxic; entirely edible
- Edibility: Fully edible, including roots and greens
- Size & Growth Rate: Matures in 30-60 days; roots can range from golf ball to softball size
Varieties
- Purple Top White Globe – Classic turnip variety with white flesh and purple top.
- Tokyo Cross – Fast-growing, smooth, all-white hybrid with a mild taste.
- Golden Ball – Sweet, yellow-fleshed variety with a tender texture.
- Scarlet Queen – Red-skinned turnip with a crisp, sweet taste.
- Hakurei – A small, tender Japanese turnip with a mild, almost fruity flavor.
Growing Conditions
Ecosystem/Climate
- Thrives in temperate and cool climates
- Best grown in spring and fall, avoiding extreme heat
Soil & pH
- Prefers well-drained, loamy soil rich in organic matter
- Ideal pH range: 6.0–7.5
- Improve soil with compost and aged manure
Temperature & Hardiness
- Best germination temperature: 50-75°F (10-24°C)
- Frost-hardy; can tolerate temperatures as low as 20°F (-7°C)
Moisture & Humidity
- Requires consistent moisture; aim for 1 inch of water per week
- Mulching helps retain soil moisture
Season
- Spring planting: 2-4 weeks before the last frost
- Fall planting: Late summer to early fall, 8-10 weeks before the first frost
Companion Plants
- Good companions: Peas, onions, garlic, nasturtiums
- Avoid planting near potatoes (competition for nutrients)
Pollination
- Not required for root development; flowers attract bees if allowed to bolt
Propagation & Seed Starting
Growing From Seed
- Seed Selection: Use organic, non-GMO turnip seeds
- Harvesting Seeds: Allow some plants to bolt and flower in the second year to collect seeds
- Germination:
- Direct sow in loose soil at ¼–½ inch deep
- Sprouts appear in 5-10 days
- Space plants 2-4 inches apart
Transplanting
- Generally not recommended; best grown from direct seeding
Cultivation & Maintenance
Organic Fertilizers
- Compost tea or fish emulsion boosts leaf growth
- Bone meal and wood ash improve root development
Mulching
- Use straw, grass clippings, or leaf mulch to retain moisture and suppress weeds
Pruning/Training
- Regularly trim outer leaves to encourage growth but leave enough for continued photosynthesis
Seasonal Care
- Protect young seedlings from unexpected frost with row covers
- In hot climates, provide partial shade
Pests & Diseases
Common Diseases
- Clubroot: Prevent by maintaining proper pH and crop rotation
- Downy mildew: Reduce humidity and space plants properly
Pest Management
- Aphids: Control with neem oil or introduce ladybugs
- Flea beetles: Use floating row covers and diatomaceous earth
- Root maggots: Deter with wood ash or beneficial nematodes
Harvesting
When & How
- Roots: Harvest 30-60 days after planting when 2-3 inches in diameter
- Greens: Harvest young leaves for salads or older ones for cooking
- Tools: Use a garden fork to gently lift roots
Signs of Readiness
- Firm, rounded roots emerging from soil
- Leaves remain green and healthy
Storage & Preservation
How to Store
- Refrigerate unwashed roots in a perforated bag for up to 2 weeks
- Store in a root cellar at 32-40°F (0-4°C) for several months
How to Preserve
- Freezing: Blanch and freeze greens and roots
- Pickling: Make lacto-fermented turnips for long-term storage
- Dehydrating: Slice and dry for soups and stews
Seed Saving
- Allow some turnips to overwinter and flower in their second year
- Harvest dry pods and store seeds in a cool, dry place
Usage & Nutrition Information
Edibility
- Both the roots and greens are edible and highly nutritious
Culinary Uses
- Raw: Sliced in salads or slaws
- Cooked: Roasted, mashed, stir-fried, or added to soups
- Greens: Used in sautés, soups, or blended into pesto
Nutritional Information (per 100g)
- Calories: ~28 kcal
- Carbohydrates: ~6g
- Fiber: ~1.8g
- Vitamin C: ~21% of Daily Value
- Potassium: ~191mg
- Folate: ~15mcg
Health Benefits
- Supports immune function with vitamin C
- Aids digestion with fiber
- Low-calorie, making it a great addition to weight-loss diets
Pet Safety
- Safe for dogs and rabbits in moderation
- Avoid feeding large amounts to pets prone to thyroid issues
Recipes
- Roasted Turnips with Honey & Thyme
- Turnip Greens Sautéed with Garlic
- Turnip and Carrot Mash
Troubleshooting
- Bitter roots? Harvest earlier or provide consistent watering
- Small roots? Overcrowding—thin seedlings properly
- Hollow roots? Inconsistent watering or over-matured turnips
Frequently Asked Questions
- How long do turnips take to grow?
- Most varieties mature in 30-60 days.
- Can you eat turnip leaves?
- Yes! Turnip greens are delicious and nutrient-rich.
- Do turnips need full sun?
- Yes, but they can tolerate partial shade.
- What is the best season for turnips?
- Spring and fall are ideal to avoid heat stress.
- How do you prevent turnip pests?
- Use row covers, companion planting, and organic deterrents like neem oil.
Resources & Further Reading
- The Organic Gardener’s Handbook of Natural Pest and Disease Control
- Online forums: Permies.com, GrowOrganic.com
- Seed Suppliers: Baker Creek Heirloom Seeds, Johnny’s Selected Seeds
By following this guide, you’ll grow delicious, nutrient-rich turnips while maintaining an eco-friendly and sustainable garden! 🌱