When to Plant Kohlrabi in Delaware (2026 Guide)
When planting kohlrabi in Delaware, timing is crucial to ensure a bountiful harvest. With the state’s two main hardiness zones, gardeners must be aware of the median last spring frost dates: April 10 for Zone 6b and April 18 for Zone 6a. The frost-free season varies from approximately 203 days in the warmer zone to around 189 days in the slightly cooler area, providing fertile ground for this unique brassica variety.
Kohlrabi is not only fun to grow but also a delicious addition to your harvest. With its crisp and juicy texture, often described as a milder, sweeter version of broccoli stem, it is perfect for salads and slaws. The short growing period of just 45–60 days from transplant means you can enjoy its fresh flavor with appropriate timing around the last frost dates.
Delaware's varying climate can present challenges like late spring frosts, especially for gardeners in Newark where April 18 marks the last frost date. Planning out your planting schedule around these key frost dates and choosing suitable varieties will help you elevate your gardening game. Whether you’re in Wilmington or Newark, kohlrabi can thrive in the right season, making it a worthwhile crop for both new and seasoned gardeners.
Planting Schedule by USDA Zone in Delaware
| Zone | Indoor start | Transplant out | Direct sow | Harvest |
|---|---|---|---|---|
| Zone 6b | Start February 15 – March 1, ~6–8 weeks before April 10 | Transplant outdoors April 20 – May 10 | Direct sow outdoors April 20 – May 10 | Harvest June 15 – July 10 |
| Zone 6a | Start February 24 – March 10, ~6–8 weeks before April 18 | Transplant outdoors April 25 – May 15 | Direct sow outdoors April 25 – May 15 | Harvest June 30 – July 20 |
Kohlrabi Planting Windows in Delaware
- Indoor start: You can start kohlrabi indoors between February 15 and March 10, depending on your specific zone.
- Transplant outdoors: Transplant your kohlrabi outdoors from April 20 to May 15 for best results in Delaware.
- Harvest: Kohlrabi can be harvested between June 15 and July 20, ensuring you pick them at the right size for optimal flavor.
Common Mistakes Growing Kohlrabi in Delaware
- One common mistake Delaware gardeners make is planting kohlrabi too late in the season. Given that kohlrabi thrives in cooler weather, waiting until after mid-May can lead to tough, fibrous bulbs as temperatures rise.
- Another issue is neglecting to consider Delaware's regional soil pH and composition, which can affect bulb quality. Conduct a soil test and amend as needed for optimal growing conditions, ensuring the soil is fertile and well-draining.
- Delaware’s humidity can lead to disease problems in brassicas, including kohlrabi. Gardeners should ensure adequate spacing and air circulation to prevent fungal diseases from taking hold during humid weather.
- Some gardeners in Delaware overlook the importance of local microclimates. Being in a colder microclimate can mean holding off planting kohlrabi until the temperatures are consistently above 50°F to ensure successful growth.
- Lastly, failing to rotate crops is a common oversight. Kohlrabi should not be planted in the same spot as other brassicas for at least three years to prevent soil-borne diseases and nutrient depletion.
Frequently Asked Questions
What if I'm in a colder pocket of Delaware?
If you live in a colder part of Delaware, consider starting your kohlrabi indoors and transplanting them once the soil warms up. Make sure to monitor nighttime temperatures and be prepared to cover them if a cold snap occurs.
Can I still plant kohlrabi in May?
Yes, you can still plant kohlrabi in May, especially if you choose fast-maturing varieties. However, be cautious of higher temperatures as kohlrabi prefers cooler conditions to develop the best flavor and texture.
How can I tell when kohlrabi is ready to harvest?
Kohlrabi should be harvested when the bulbs reach about 3 inches in diameter for optimal taste. If they grow larger than 4 inches, they may become tough and woody, losing that crunchy quality you want.
How do I prevent disease in my kohlrabi?
To prevent disease in kohlrabi, ensure proper spacing between plants for good air circulation, water them at the base rather than overhead, and rotate your crops yearly. Good sanitation practices can also help mitigate disease spread.
What should I do if kohlrabi isn't growing well?
If your kohlrabi is struggling, check the soil conditions first. Ensure it's well-draining and rich in organic matter. Also, assess light exposure and water levels, as both play critical roles in healthy growth.
Keep Learning
City guides in Delaware
Other crops in Delaware
Typical fall sowing window for Kohlrabi in Delaware: August 16 – September 6.