If you’re looking for a unique and easy vegetable to add to your garden, kohlrabi is a fantastic choice. You might be wondering, how long does kohlrabi take to grow? The quick answer is that most varieties are ready for harvest in just 50 to 70 days from sowing seeds.
This makes it one of the faster-growing cool-season crops. Its quick turnaround means you can often plant it in both spring and fall for two harvests in a single year. Let’s get into the details so you can enjoy this crisp, mild vegetable from your own backyard.
How Long Does Kohlrabi Take To Grow
The total time from seed to harvest depends on the specific variety you choose. Fast-maturing types, like ‘Quickstar’ or ‘Korridor,’ can be ready in as little as 45 days. Standard green or purple varieties typically take 55 to 60 days. Larger, storage-type kohlrabi might need up to 70 days to reach full size.
Remember, this count starts from the day you sow the seeds directly in the garden or from transplanting. Kohlrabi grows as a fast pace, so it’s important to keep an eye on it as it nears maturity.
Choosing the Right Kohlrabi Variety
Your choice of seed directly impacts your growing timeline. Here’s a quick guide:
- Early Varieties (45-50 days): ‘Quickstar’, ‘Winner’. Perfect for quick spring crops before summer heat.
- Mid-Season Varieties (55-60 days): ‘Grand Duke’, ‘Purple Vienna’. The most common and reliable types for most gardens.
- Storage Varieties (65-70+ days): ‘Gigante’, ‘Superschmelz’. These grow very large and store well into winter.
The Ideal Growing Conditions for Speed
To hit that 50-70 day target, kohlrabi needs the right conditions. Stressing the plant will slow it down.
Sunlight and Temperature
Kohlrabi thrives in full sun, meaning at least 6 hours of direct light daily. It is a cool-season crop. The sweetest bulbs develop in temperatures between 40°F and 75°F. Growth stalls in hot weather, which can also cause the bulb to become woody.
Soil Requirements
The soil is key to fast growth. Kohlrabi prefers:
- Well-Draining Soil: Soggy roots will stunt growth.
- Fertile & Rich in Organic Matter: Mix in compost before planting.
- Soil pH: Slightly acidic to neutral, between 6.0 and 7.5.
Step-by-Step: Planting for a Fast Harvest
1. Timing Your Planting
For a spring harvest, sow seeds directly in the garden 2-4 weeks before your last expected frost date. You can also start seeds indoors a few weeks earlier for a head start. For a fall harvest, plant seeds about 8-10 weeks before your first expected fall frost. This is often in mid-to-late summer.
2. Sowing Seeds Directly
- Loosen the soil to about 12 inches deep.
- Plant seeds ¼ to ½ inch deep.
- Space seeds about 1 inch apart in rows.
- Later, thin seedlings to stand 4-6 inches apart. Crowded plants won’t bulb properly.
3. Starting Seeds Indoors
If you want to get a jump on spring, start seeds indoors 4-6 weeks before transplanting outside. Use cell trays, and transplant the seedlings when they have 3-4 true leaves. Harden them off for a week before putting them in the ground.
Caring for Your Kohlrabi Plants
Consistent care ensures your kohlrabi matures on schedule and stays tender.
Watering and Mulching
Kohlrabi needs consistent moisture. Aim for about 1 inch of water per week, from rainfall or watering. Inconsistent watering leads to tough, cracked bulbs. Apply a layer of straw or shredded leaves mulch around plants to retain soil moisture and keep roots cool.
Fertilizing for Growth
If your soil is already rich, little extra fertilizer is needed. If growth seems slow, a light side-dressing with a balanced, nitrogen-rich fertilizer about 3 weeks after planting can give them a boost. Avoid over-fertilizing, which promotes leafy growth instead of bulb growth.
Weeding and Pest Watch
Keep the area weed-free to reduce competition for nutrients. Common pests include cabbage worms and flea beetles. Check leaves regularly. You can use floating row covers immediately after planting to prevent pest problems without sprays.
How to Know When Kohlrabi is Ready
Don’t just rely on the calendar. The best indicator is the size of the bulb, or swollen stem. Harvest when the bulb is about 2 to 3 inches in diameter—roughly the size of a tennis ball. At this size, the flavor is sweet and the texture is crisp. If you leave it too long, the bulb becomes fibrous and woody.
Use a sharp knife to cut the stem just below the bulb. You can also harvest the younger, tender leaves to eat like kale or collards.
Common Problems That Delay Growth
- Bolting: If plants are exposed to a long period of cold followed by heat, they may “bolt” (send up a flower stalk). This stops bulb growth. Choose bolt-resistant varieties for spring and use proper timing.
- Woody Bulbs: Caused by harvesting too late, uneven watering, or excessive heat.
- Slow Bulb Formation: Often due to overcrowding, poor soil fertility, or insufficient water.
Succession Planting for Continuous Harvest
Since kohlrabi grows so quickly, you can plant it multiple times. Instead of planting all your seeds at once, sow a small row every 2-3 weeks in the spring. This staggers your harvest so you have a continuous supply of tender bulbs rather than a glut all at once.
Storing Your Kohlrabi Harvest
Once harvested, you can store kohlrabi for later use. Trim off the leaves (store them separately like greens). The unwashed bulbs will keep in a plastic bag in your refrigerator crisper drawer for 2-4 weeks. For long-term storage, varieties like ‘Gigante’ can be kept in a cool, humid root cellar for several months.
Frequently Asked Questions (FAQ)
Can you grow kohlrabi in containers?
Absolutely! Choose a pot that is at least 12 inches deep and wide. Use quality potting mix and ensure it has drainage holes. Container plants may need water more frequently.
What are good companion plants for kohlrabi?
Kohlrabi grows well with onions, beets, and cucumbers. Avoid planting it near pole beans or tomatoes, as they can compete for space and nutrients.
Why are my kohlrabi bulbs not swelling?
The most common reasons are planting too close together (failure to thin), not enough sunlight, or a lack of consistent water. Check these factors if your plants seem stalled.
Can you eat kohlrabi leaves?
Yes! The young leaves are edible and nutritious. Saute them like spinach or add them to soups. Just be sure not to remove to many leaves from a growing plant, as it needs some to support bulb growth.
Is kohlrabi a root vegetable?
This is a common misconception. The part we eat is actually a swollen stem that grows just above the soil line, not a root. This is why it grows so quickly compared to true root vegetables like carrots.
Growing kohlrabi is a simple and rewarding garden project. By choosing a quick-maturing variety, providing consistent moisture, and harvesting at the right time, you’ll be enjoying your own homegrown kohlrabi in less than two months. Its unique apperance and mild, sweet flavor make it a fun addition to any garden and kitchen.