Hart's Tongue Fern vs Kohlrabi Plant Comparison
Compare these two plants side by side — care needs, key differences, and which is right for your home.
Hart's Tongue Fern
Asplenium scolopendrium
Hart's Tongue Fern is an evergreen fern characterized by its simple, strap-shaped fronds. These fronds, resembling a deer's tongue, are glossy green and have a leathery texture. It's primarily an outdoor plant, thriving in cool, damp, shaded environments like woodlands and limestone cliffs. While it can be grown indoors, it requires specific conditions to mimic its natural habitat. People grow it for its unique foliage and architectural interest in shaded gardens or as a curiosity indoors.
Kohlrabi
Brassica oleracea var. gongylodes
Kohlrabi is a biennial vegetable cultivated as an annual, known for its swollen, globular stem that grows above ground. It features a crisp, mild flavor similar to a turnip or cabbage. The plant has long-stalked leaves emerging from the bulbous stem. It is primarily grown outdoors in gardens and farms for its edible stem and leaves. While it can be started indoors, it requires full sun and ample space to thrive, making it challenging to grow to maturity indoors. People grow kohlrabi for its unique texture and flavor in salads, stir-fries, and other culinary applications.
Quick Plant Comparison
| Feature | Hart's Tongue Fern | Kohlrabi |
|---|---|---|
| Light | Partial to full shade. Avoid direct sunlight. | Full sun (at least 6 hours of direct sunlight daily) |
| Watering | Every 5-7 days, depending on humidity and temperature | Every 2-3 days outdoors, depending on weather conditions |
| Humidity | 60-80% | 40-60% |
| Temperature | 13-18°C | 15-24°C |
| Care Level | Moderate | Expert |
| Growth Rate | Slow | Moderate |
| Max Height | 30-60 cm | 30-45 cm (outdoors) |
| Pet Safety | ✅ Safe | ✅ Safe |
| Soil | Well-draining, humus-rich soil. A mix of peat moss, perlite, and garden soil works well. | Well-draining, fertile soil rich in organic matter |
| Beginner Friendly | With Caution | ❌ No |
| Weekly Maintenance | 10 minutes weekly | 15-30 minutes weekly |
🔬 Botanical Information — Comparing These Plants
Hart's Tongue Fern
| Scientific Name | Asplenium scolopendrium |
|---|---|
| Family | Aspleniaceae |
| Native To | Europe, eastern North America, and parts of Asia |
| Also Known As | Hart's Tongue Fern, Hart's-tongue Fern |
| Leaves | The leaves, or fronds, are simple, undivided, and strap-shaped, typically 15-45 cm long and 3-6 cm wide. They are a glossy, bright green color with a leathery texture and have slightly wavy edges. The underside of the fronds features rows of sori (spore-producing structures). |
| Flowers | Ferns do not flower. They reproduce via spores. |
Kohlrabi
| Scientific Name | Brassica oleracea var. gongylodes |
|---|---|
| Family | Brassicaceae |
| Native To | Northern Europe |
| Also Known As | German turnip, turnip cabbage |
| Leaves | The leaves of kohlrabi are typically bluish-green, broad, and have a slightly waxy texture. They are attached to the stem by long, slender stalks. The leaf shape can vary, but they are generally oval or rounded with slightly serrated edges. |
| Flowers | Kohlrabi will flower in its second year if allowed to overwinter. The flowers are typical of the Brassica family, with four petals arranged in a cross shape, usually yellow or white. Flowering is rare when grown as an annual for its bulb. |
📏 Size & Growth — Plant Comparison
Hart's Tongue Fern
Kohlrabi
🌱 Propagation — Comparing Plant Growth
Hart's Tongue Fern
Methods: Spores, Division
Difficulty: Moderate
Tips: Spores require a sterile environment and high humidity to germinate. Division is best done in spring, separating the rhizomes carefully.
Kohlrabi
Methods: Seed
Difficulty: Easy
Tips: Start seeds indoors 4-6 weeks before the last frost or direct sow outdoors after the last frost. Keep soil consistently moist.
✨ Benefits & Features — Comparing Plant Value
Hart's Tongue Fern
The Hart's Tongue Fern is unique due to its undivided, strap-shaped fronds, which are unlike the typical divided fronds of most ferns. The sori are arranged in neat rows on the underside of the fronds, adding to its distinctive appearance.
- ✓ Adds unique texture and visual interest to shaded areas.
- ✓ Non-toxic to pets and children.
- ✓ Can help improve humidity levels in a small area.
- ✓ Offers a calming and natural aesthetic.
- ✓ Relatively low-maintenance once established in the right conditions.
- 🌬️ NASA-verified air purifier
- 🐾 Pet Safe
Kohlrabi
Kohlrabi is unique due to its edible, swollen stem that grows above ground, unlike root vegetables. Its mild flavor and crisp texture make it a versatile ingredient in various dishes. The plant also offers edible leaves, adding to its appeal.
- ✓ Provides fresh, nutritious vegetables
- ✓ Adds visual interest to the garden
- ✓ Encourages healthy eating habits
- ✓ Offers a unique culinary ingredient
- ✓ Supports sustainable living
- 🐾 Pet Safe
📅 Maintenance Schedule — Plant Care Comparison
Hart's Tongue Fern
Kohlrabi
🌞 Light Requirements
Hart's Tongue Fern
Partial to full shade. Avoid direct sunlight.
Low light tolerant: ✅ Yes
Kohlrabi
Full sun (at least 6 hours of direct sunlight daily)
Low light tolerant: ❌ No
💧 Watering Needs
Hart's Tongue Fern
Keep the soil consistently moist but not waterlogged. Water when the top inch of soil feels slightly dry. Overwatering can lead to root rot, while underwatering will cause the fronds to brown and crisp.
Kohlrabi
Water deeply when the top inch of soil feels dry. Avoid overwatering, which can lead to rot. Consistent moisture is important for bulb development. Signs of underwatering include wilting leaves and stunted growth. Overwatering can cause yellowing leaves and a mushy stem.
🌡️ Temperature & Humidity
Hart's Tongue Fern
Temperature: 13-18°C
Humidity: 60-80%
Kohlrabi
Temperature: 15-24°C
Humidity: 40-60%
🤔 Which Plant Is Right For You?
Hart's Tongue Fern
Asplenium scolopendriumExperienced plant enthusiasts who can provide the specific environmental conditions required for healthy growth.
✅ Choose This Plant If...
- You appreciate unique foliage and architectural plants.
- You have a shaded, humid environment in your home or garden.
- You are willing to provide consistent moisture and humidity.
- You enjoy a plant that adds a touch of woodland charm.
- You are looking for a non-toxic plant for a home with pets.
❌ Skip This Plant If...
- You have a dry indoor environment.
- You tend to overwater plants.
- You don't have a shaded location.
- You are a beginner plant owner.
Kohlrabi
Brassica oleracea var. gongylodesGardeners looking for a unique and nutritious vegetable to grow outdoors.
✅ Choose This Plant If...
- You have a sunny garden space.
- You enjoy growing your own vegetables.
- You want a unique and nutritious addition to your diet.
- You are looking for a relatively fast-growing crop.
- You enjoy the taste of cabbage and turnips.
❌ Skip This Plant If...
- You lack sufficient outdoor space.
- You cannot provide at least 6 hours of direct sunlight daily.
- You are looking for a low-maintenance indoor plant.
🎯 Quick Verdict
⚡ Key Differences Between These Plants
Hart's Tongue Fern is rated Moderate care level, while Kohlrabi is Expert.
Hart's Tongue Fern has slow growth, while Kohlrabi grows moderate.
💡 Pro Tips For Comparing These Plants
Hart's Tongue Fern Care Tips
Hart's Tongue Fern requires consistent moisture, high humidity, and shade. Indoor cultivation can be challenging due to the need for specific environmental conditions. Providing adequate humidity and avoiding direct sunlight are crucial for success.
- Provide consistent moisture, but avoid soggy soil.
- Increase humidity by misting regularly or using a humidifier.
- Avoid direct sunlight, which can scorch the fronds.
- Use a well-draining potting mix rich in organic matter.
- Fertilize sparingly during the growing season.
Kohlrabi Care Tips
Kohlrabi is primarily an outdoor plant that requires full sun and consistent moisture. Growing it indoors is challenging due to the high light requirements and space needed for bulb development. It's best suited for experienced gardeners with outdoor space.
- Start seeds indoors for an earlier harvest.
- Ensure well-draining soil to prevent rot.
- Provide consistent moisture for optimal bulb development.
- Fertilize regularly during the growing season.
- Protect from pests like aphids and cabbage worms.
⚠️ Common Problems & Solutions — Plant Care Comparison
Hart's Tongue Fern
Kohlrabi
❓ Frequently Asked Questions — Comparing These Plants
Hart's Tongue Fern
What are the light requirements for Hart's Tongue Fern?
Hart’s Tongue Fern thrives in bright, indirect light. Direct sunlight can scorch its delicate fronds, leading to brown spots and stunted growth. A north-facing window is often ideal, providing ample light without the harsh intensity. East-facing windows can also work well, as long as the morning sun is not too strong. Avoid placing the fern in direct south or west-facing windows unless you can provide significant shading. Insufficient light can result in pale, leggy growth and a loss of the vibrant green color. Regularly assess your fern’s light exposure and adjust its placement as needed to ensure optimal growth and health.
How do I care for Hart's Tongue Fern?
Hart’s Tongue Fern requires specific care to thrive. Provide bright, indirect light, avoiding direct sunlight which can scorch the fronds. Maintain consistently moist soil, but avoid overwatering which can lead to root rot. Water when the top inch of soil feels dry. High humidity is crucial; aim for 60-80% humidity. Use a well-draining potting mix rich in organic matter. Fertilize sparingly during the growing season (spring and summer) with a diluted liquid fertilizer. Keep temperatures between 60-70°F (15-21°C). Prune away any dead or damaged fronds to encourage new growth. Repot only when necessary, usually every 2-3 years. Protect from drafts and sudden temperature changes. Regular misting is beneficial.
How do I propagate Hart's Tongue Fern?
Hart’s Tongue Fern can be propagated through division or spores. For division, carefully separate the rhizome into sections, ensuring each section has healthy fronds and roots. Plant each section in its own pot with well-draining soil. To propagate from spores, collect spores from mature fronds. Sow the spores on a sterile growing medium and maintain high humidity. Germination can take several weeks. Division is the easier and more common method. Ensure each division has adequate roots before repotting. Provide high humidity and indirect light during the propagation process.
Kohlrabi
What are the light requirements for Kohlrabi?
Kohlrabi thrives in full sun, requiring at least 6 hours of direct sunlight per day to produce healthy bulbs. Insufficient light can lead to leggy growth and smaller, less flavorful bulbs. In hotter climates, providing some afternoon shade can prevent the plant from bolting (prematurely going to seed). When growing indoors, place Kohlrabi near a south-facing window or use grow lights to supplement natural light. Rotate the plants regularly to ensure even light exposure on all sides. Monitor the leaves for signs of insufficient light, such as pale color or elongated stems, and adjust the light accordingly.
How do I care for Kohlrabi?
Kohlrabi requires well-draining soil rich in organic matter. Plant seeds directly in the garden or start indoors 4-6 weeks before the last frost. Space plants 6-8 inches apart in rows 12-18 inches apart. Water regularly, keeping the soil consistently moist but not waterlogged. Fertilize every 2-3 weeks with a balanced fertilizer, paying attention to potassium levels to promote strong bulb development. Kohlrabi prefers full sun but can tolerate partial shade, especially in warmer climates. Harvest when the bulb reaches 2-3 inches in diameter for the best flavor and texture. Protect from pests like cabbage worms and aphids with appropriate organic pest control methods. Rotate crops annually to prevent soilborne diseases.
How do I propagate Kohlrabi?
Kohlrabi is typically propagated by seed, but it is possible to propagate it through vegetative methods, although less common.
Last updated: April 26, 2026 — Plant care data reviewed and verified by our editorial team.