When to Plant Kohlrabi in New Hampshire (2026 Guide)
Kohlrabi is a unique and delicious vegetable that is not only easy to grow but also offers a refreshing crunch and sweet flavor in the kitchen. With its bulb-like swollen stem, this unusual brassica is perfect for a wide variety of culinary uses, from salads to roasting. In New Hampshire, the growing conditions can vary widely, making the right planting times essential for gardeners eager to harvest this tasty crop.
In New Hampshire, residents in Zone 5b can expect their last spring frost around May 11, while those in Zone 6a have an earlier date of April 28. Understanding these frost dates is crucial for successful planting and harvesting. Kohlrabi thrives in cooler weather, so careful timing is necessary to ensure you avoid frost damage and enjoy the best flavor and texture from your harvest.
Planting kohlrabi at the right times can maximize your yield and ensure success. The frost-free growing season averages about 142 days in Zone 5b and around 164 days in Zone 6a, allowing ample time to grow and enjoy this nutritious vegetable. Let’s explore the best planting and harvesting strategies specific to New Hampshire climates to make the most out of your kohlrabi garden.
Planting Schedule by USDA Zone in New Hampshire
| Zone | Indoor start | Transplant out | Direct sow | Harvest |
|---|---|---|---|---|
| Zone 5b | Start March 15 – March 30, ~6–8 weeks before May 11 | Transplant outdoors May 15 – May 30, after the last frost | Direct sow outdoors May 1 – May 20, once the soil warms up | Harvest June 30 – July 15, when bulbs reach 3 inches |
| Zone 6a | Start March 1 – March 15, ~6–8 weeks before April 28 | Transplant outdoors April 30 – May 15, after the last frost | Direct sow outdoors April 15 – April 30, once the soil is workable | Harvest June 15 – June 30, when bulbs reach 3 inches |
Kohlrabi Planting Windows in New Hampshire
- Indoor start: Start kohlrabi seeds indoors between March 1 – March 30.
- Transplant outdoors: Transplant kohlrabi outdoors starting from April 30 – May 30.
- Harvest: Kohlrabi is ready for harvest from June 15 – July 15.
Common Mistakes Growing Kohlrabi in New Hampshire
- One common mistake in New Hampshire is planting kohlrabi too late. Given the relatively short growing season, planting should be timed carefully so that the crop matures before the first frost, especially in Zone 5b where the frost comes later than in other regions.
- New Hampshire's unpredictable weather, including late spring snows, can catch gardeners off guard. Being vigilant about frost dates and keeping an eye on sudden weather changes is crucial to avoid damaging young kohlrabi transplants.
- Planting kohlrabi too closely can lead to poor air circulation and enhance the risk of pests and diseases. New Hampshire gardeners should ensure they follow recommended spacing guidelines to allow adequate room for each plant to grow and thrive.
- Many gardeners in New Hampshire might overlook the importance of soil health. Ensuring the right soil composition and nutrients is vital for kohlrabi, particularly in areas with heavy clay or alkaline soils, which can impede development.
- Misjudging the harvest time is another frequent oversight. Kohlrabi should be harvested when the bulbs reach about 3 inches in diameter, as waiting too long can result in woody and less palatable crops, a mistake not uncommon in New Hampshire's gardening circles.
Frequently Asked Questions
What if I'm in a cold pocket of New Hampshire?
If you're located in a colder area, consider starting seeds indoors earlier to give kohlrabi young plants a better chance. Use the indoor starting window to help bridge that gap effectively.
Can I still plant kohlrabi in May?
Yes, you can plant kohlrabi in May! Just ensure to do so before the last frost date in your zone, and consider direct sowing for optimal growth. Use the transplant window if you started seeds indoors.
How much space does kohlrabi need?
Kohlrabi generally requires about 12 to 18 inches of space between plants in the garden. Proper spacing allows for air circulation, helping reduce disease and promoting healthy bulb development.
What are the ideal soil conditions for kohlrabi?
Kohlrabi prefers well-draining, fertile soil with a pH between 6.0 and 7.0. Testing your soil and amending it accordingly can significantly improve your kohlrabi yields in New Hampshire's varied soil types.
Can I eat the leaves of kohlrabi?
Yes, the leaves of kohlrabi are edible and nutritious! They can be cooked just like other leafy greens, such as kale or collard greens, providing additional harvests from your kohlrabi plants.
Keep Learning
City guides in New Hampshire
Other crops in New Hampshire
Typical fall sowing window for Kohlrabi in New Hampshire: July 19 – August 9.