Heirloom Kale Planting Guide: From Seed to Harvest

Heirloom kale (Brassica oleracea var. sabellica) has become increasingly popular among home gardeners and organic farmers, thanks to its rich, earthy flavors and the robust nutrition it offers. Known for its distinctive taste, high adaptability, and stunning appearance, heirloom kale can be grown in many climates and environments, making it a fantastic choice for both beginner and experienced gardeners.

This Heirloom Kale Planting Guide will walk you through everything you need to know about how to grow heirloom kale, from choosing varieties to planting, caring for, and harvesting these nutritious greens.

Quick Start Heirloom Kale Planting Guide – Complete Planting Guide Below

Heirloom / Open Pollinated Kale is a short season brassica that performs best in cool weather and can tolerate frost when established. For spring planting of Kale, start seeds indoors 4-6 weeks before last frost, or direct sow after danger of hard frost. In warm climates you can plant Kale in late summer for fall harvest. In hot climates you can plant Kale in the fall for a winter harvest. Plant Kale in full sun in more mild climates, or partial shade in very hot summer climates.

Sow Kale seeds ½” deep, 3″ apart, in rows 18-24″ apart. Germination should occur in 5-17 days in soil 55-75°F. When Kale plants reach 3-5″, thin to 12-18″ apart. Outer leaves can be harvested at about 8-10″ long, Avoid picking the inner leaves to avoid damaging the growing point. A light frost brings out the sweetness in fall or winter crops.

The Complete Planting Guide for Heirloom Kale: From Seed to Harvest

What is Heirloom Kale?

Heirloom kale refers to varieties that have been grown for generations, typically at least 50 years, without significant alteration from modern plant breeding. Unlike hybrid kales, heirloom varieties are open-pollinated, meaning their seeds can be saved and replanted to grow true-to-type plants. This characteristic makes heirloom kale a fantastic choice for sustainable gardening and those looking to preserve traditional, non-GMO plant varieties.

With a long history, heirloom kale offers unique flavors, colors, and textures. Notable varieties include the compact ‘Dwarf Blue Curled Scotch,’ the frilly ‘Red Russian,’ and the richly dark ‘Lacinato’ or dinosaur kale. These varieties are not only visually appealing but also offer different culinary qualities, from peppery to mild and slightly sweet.

Selecting the Right Heirloom Kale Variety

The first step in your Heirloom Kale Planting Guide is to select the best variety for your garden based on climate, space, and taste preferences. Here are some popular heirloom varieties:

• Dwarf Blue Curled Scotch: This variety is known for its small, compact size, curly leaves, and resilience in colder weather. It’s ideal for smaller spaces and container gardening.
• Red Russian Kale: Featuring flat, frilly-edged leaves with purple hints, Red Russian kale is mildly sweet and tender, making it excellent for fresh salads.
• Lacinato Kale (Dinosaur Kale): This dark, bumpy-leaved kale has a nutty flavor and is prized for cooking, especially in Italian dishes.
• Siberian Kale: With large, tender leaves, Siberian kale is hardy and does well in cool climates, making it a great option for northern gardeners.

Each heirloom kale has its own growth characteristics and flavor profile, so don’t hesitate to try a few varieties to find the perfect fit for your needs.

Optimal Growing Conditions for Heirloom Kale

This section of the Heirloom Kale Planting Guide covers the ideal conditions for planting heirloom kale and ensuring optimal growth. While heirloom kale is highly adaptable, it generally prefers cool weather. Most varieties grow best in temperatures between 55°F and 75°F (13°C and 24°C), making spring and fall the ideal planting times. Kale’s flavor improves with a touch of frost, adding sweetness, so early spring or late summer planting for fall harvests is recommended.

Sunlight and Soil Needs

• Light Requirements: Kale thrives in full sun but can tolerate partial shade, especially in hot climates. Aim for 6–8 hours of sunlight each day to promote vigorous growth.
• Soil Requirements: Kale grows best in rich, well-draining soil with a pH between 6.0 and 7.5. Adding compost or well-rotted manure before planting improves the soil’s nutrient content and structure, which promotes robust growth.

Planting Heirloom Kale from Seeds or Seedlings

Knowing how to grow heirloom kale successfully starts with proper planting techniques. You can plant heirloom kale either from seeds or seedlings, and the method is simple.

1. Soil Preparation: Begin by working 1–2 inches of compost into the soil. If your soil has poor drainage, consider adding amendments to enhance its quality.
2. Sowing Seeds: Plant seeds about ¼ to ½ inch deep, spacing each seed 8–10 inches apart, with rows spaced about 18 to 24 inches apart.
3. Thinning Seedlings: Once seedlings appear (5–10 days after planting), thin them to a spacing of 12–18 inches to allow adequate airflow and growth room.
4. Transplanting: If using seedlings, wait until they reach 3–4 inches in height. Gradually expose them to outdoor conditions over 7–10 days before transplanting.

Container Planting

Growing kale in containers is an excellent option for limited space. Choose pots with good drainage and a diameter of at least 12 inches. Use a nutrient-rich potting mix, amended with compost, to ensure your heirloom kale has a healthy environment to thrive.

Caring for Heirloom Kale Plants

Once you’ve planted, caring for your kale properly is essential to get the best results. Here’s how to maintain your plants:

Watering

Kale needs consistent moisture to grow well. Aim to water deeply to keep the soil moist, but avoid overwatering, which can lead to root rot. A general rule is to provide about 1–1.5 inches of water per week, adjusting as necessary based on climate and rainfall. In hotter conditions, apply mulch to help retain soil moisture and keep roots cool.

Fertilizing

Heirloom kale isn’t a heavy feeder, but occasional feeding will support healthy growth. Applying a balanced organic fertilizer, such as a 10-10-10 formula, every 4–6 weeks will maintain vigor. Avoid excess nitrogen, which can lead to excess leafy growth and diminished flavor.

Harvesting Heirloom Kale

Harvesting heirloom kale is a rewarding process, and it can be done at various stages, depending on your desired use. Whether you’re looking for tender baby greens or mature leaves for cooking, proper harvesting techniques will encourage continuous growth and a prolonged harvest season.

Harvesting Baby Kale Leaves

For tender, young leaves perfect for salads or fresh eating, you can begin harvesting baby kale leaves when they’re about 3–4 inches tall, typically 25–30 days after planting. Use scissors or a sharp knife to cut individual leaves, starting from the outermost leaves and leaving the central growing tip intact. This method encourages new growth, allowing you to enjoy ongoing harvests throughout the season.

Harvesting Mature Kale Leaves

Mature leaves are ready to be harvested within 50–75 days, depending on the variety. To harvest mature leaves, cut the outer leaves at the base of the plant, working your way around the stem. Avoid removing more than one-third of the leaves at a time, as this can stress the plant and reduce its productivity. Continue to let the central, newer leaves grow, which will extend the plant’s productive life and give you multiple harvests.

Tips for Harvesting Kale for the Best Flavor

Kale’s flavor is often enhanced by cool temperatures, so harvesting after a light frost can make the leaves sweeter and milder. If you’re growing kale in cooler months, you’ll notice that frost-kissed leaves are tender and ideal for eating raw or lightly cooked.

Post-Harvest Care and Storage

After harvesting, wash the leaves gently in cool water to remove any dirt or insects. Pat them dry or use a salad spinner, then store kale in the refrigerator in a breathable bag or container. Kale can stay fresh for up to a week when stored properly. For long-term storage, blanch the leaves briefly in boiling water, cool them in ice water, and freeze them for up to six months, preserving flavor and nutrients for future use.

By following these harvesting practices, you’ll enjoy a continuous supply of fresh, flavorful kale from your garden.

Benefits of Growing Heirloom Kale

Growing heirloom kale offers not only culinary enjoyment and health benefits but also supports biodiversity and sustainable gardening. By planting heirloom varieties, gardeners help preserve traditional plant genetics, contributing to crop resilience against climate challenges.

Kale is packed with essential vitamins and antioxidants. Growing your own kale provides greens at their freshest, most nutrient-dense stage, adding significant health value to your diet.

Cooking with Heirloom Kale

Heirloom kale’s diverse textures and flavors make it a versatile ingredient in many dishes, from fresh salads to hearty soups. Here are a few favorite ways to use heirloom kale:

• Raw: Add baby kale leaves to salads for a fresh, tender bite, or blend them in smoothies.
• Sautéed: Cook mature kale leaves quickly with garlic and olive oil for a simple, nutritious side.
• Soups and Stews: Kale adds flavor, nutrition, and vibrant color to soups, stews, and casseroles.
• Kale Chips: Make homemade kale chips by baking seasoned leaves for a healthy, crunchy snack.

Experiment with different heirloom varieties to enjoy a wide range of flavors and textures in your cooking.

Managing Pests and Diseases in Heirloom Kale

While heirloom kale is generally a hardy crop, it can still face challenges from common pests and diseases. Understanding these potential issues and how to address them will help ensure healthy plants and a productive harvest. Here’s a guide to keeping pests and diseases under control in your heirloom kale garden.

Common Pests in Heirloom Kale

1. Aphids: These small, soft-bodied insects can cluster on the undersides of kale leaves, sucking sap from the plant and weakening it over time. Aphid infestations can lead to yellowed, curled leaves and reduced plant vigor. To control aphids, try spraying the plants with a strong stream of water to dislodge them or use insecticidal soap for heavier infestations. Introducing beneficial insects like ladybugs can also help keep aphid populations in check.
2. Cabbage Worms: The larvae of cabbage moths, cabbage worms are green caterpillars that feed on kale leaves, creating holes and damaging plant tissue. You can handpick these pests, use row covers to prevent moths from laying eggs, or apply an organic insecticide like Bacillus thuringiensis (Bt), which specifically targets caterpillars without harming beneficial insects.
3. Flea Beetles: These tiny, jumping beetles can cause numerous small holes in kale leaves, giving them a “shotgun” appearance. Flea beetles are most problematic during early spring and can stunt young plants. Row covers can protect plants from these pests, and using a neem-based spray may reduce flea beetle activity.
4. Slugs and Snails: Slugs and snails are common in damp conditions and can cause significant leaf damage. To control them, use copper tape around your garden bed edges, set up beer traps, or place diatomaceous earth around your plants as a barrier.

Common Diseases in Heirloom Kale

1. Downy Mildew: This fungal disease appears as yellow or white patches on the upper sides of leaves, with gray mold underneath. Downy mildew thrives in damp, humid conditions. To prevent it, space plants adequately for good airflow, avoid overhead watering, and remove affected leaves to limit disease spread.
2. Black Rot: Black rot causes dark, V-shaped lesions on leaf edges, often accompanied by a foul smell. The disease spreads through water and can be difficult to control once established. Rotate your crops yearly to prevent buildup in the soil, and avoid working with wet plants to reduce the risk of spreading the bacteria.
3. Clubroot: This soil-borne disease causes swelling and deformities on the roots, stunting plant growth and potentially killing young plants. Clubroot is challenging to manage since it can persist in the soil for many years. Improve soil drainage, practice crop rotation, and raise the soil pH with lime to create less favorable conditions for the disease.
4. Powdery Mildew: Powdery mildew forms a white, powdery coating on kale leaves, particularly during warm, dry weather. While it’s rarely fatal, it can weaken plants and reduce yield. Space plants well, water at the base rather than overhead, and remove any affected leaves to reduce mildew spread.

Prevention and Best Practices for Disease Control

1. Crop Rotation: Rotate your kale and other brassicas yearly to prevent soil-borne diseases from accumulating.
2. Watering Practices: Water kale at the base, avoiding overhead watering, to keep foliage dry and reduce the risk of fungal diseases.
3. Soil Management: Maintain healthy soil by adding compost and other organic matter. This helps promote disease resistance and improves overall plant health.
4. Hygiene: Remove plant debris from your garden at the end of each season, as many pests and diseases can overwinter in old plant material.

By staying vigilant and following these pest and disease management practices, you’ll be able to enjoy a thriving crop of heirloom kale with minimal issues.

Storing and Preserving Heirloom Kale

Once you’ve harvested your heirloom kale, proper storage and preservation methods will help you enjoy its fresh flavor and nutrition well beyond the growing season. Whether you prefer to store it short-term for fresh use or preserve it for months, there are several options to keep your kale at its best.

Short-Term Storage for Fresh Kale

For short-term use, store kale in the refrigerator where it can remain fresh for up to a week. After harvesting, rinse the leaves gently in cool water to remove any dirt or insects, and pat them dry. Store kale in a perforated plastic bag or a breathable container, which will help maintain its crispness by allowing airflow and reducing excess moisture that can cause spoilage. Place the container in the crisper drawer of your refrigerator, where the temperature is cool and consistent.

Freezing Kale for Long Term Preservation

Freezing is one of the best ways to preserve kale, as it retains much of its nutrient content, flavor, and texture when prepared correctly. To freeze kale:

1. Blanch the Leaves: Start by bringing a pot of water to a rolling boil. Place washed and trimmed kale leaves in the boiling water for about 2–3 minutes. Blanching helps retain the color, flavor, and nutrients of kale and also stops enzyme activity that can lead to spoilage.
2. Cool Quickly: After blanching, immediately transfer the kale to an ice bath to halt the cooking process. Leave it in the cold water for about 2–3 minutes or until completely cool.
3. Dry and Pack: Drain the kale thoroughly and pat it dry to prevent freezer burn. Place the leaves in freezer-safe bags or containers, removing as much air as possible to maintain freshness. Label and date the bags for easy tracking.

Properly frozen kale can last up to 6–8 months, making it an excellent addition to soups, stews, and smoothies during the off-season.

Dehydrating Kale for Kale Chips or Powder

Dehydrating kale allows you to create healthy snacks or make a powder that can be added to various dishes for an extra nutrient boost.

1. Prepare the Leaves: Wash and pat dry the leaves thoroughly, removing tough stems. You can keep the leaves whole or cut them into smaller pieces, depending on your preference.
2. Dehydrate: Arrange the leaves in a single layer on a dehydrator tray or baking sheet (if using an oven). Set your dehydrator or oven to a low temperature, around 125°F (50°C). Dehydrate for 4–6 hours until the leaves are completely crisp.
3. Store: Store dried kale in airtight containers in a cool, dark place. To make kale powder, crumble or grind the dried leaves and store them in a jar, where they’ll last up to a year.

Pickling Kale Stems

If you find yourself with leftover kale stems, consider pickling them for a tangy, nutrient-packed snack. Simply cut the stems into bite-sized pieces, then pack them into a sterilized jar. Prepare a pickling brine of vinegar, water, salt, and any desired spices (like garlic, dill, or peppercorns), then pour the brine over the stems. Seal the jar and refrigerate for a few days to allow the flavors to develop. Pickled kale stems will stay fresh for several weeks in the refrigerator and can be enjoyed as a crunchy addition to salads and sandwiches.

By exploring these storing and preserving methods, you’ll be able to enjoy the taste and health benefits of heirloom kale long after the growing season has ended.

Saving Seeds from Heirloom Kale

Saving seeds from heirloom kale is a rewarding practice that helps preserve unique plant genetics and allows you to grow a continuous supply of this nutritious green each year. Since heirloom kale varieties are open-pollinated, you can save seeds that will produce plants with the same characteristics as the parent plant, maintaining the true-to-type nature of your kale.

Timing the Seed Harvest

Kale is a biennial, which means it generally flowers and sets seeds in its second year. After overwintering, kale plants will produce small, yellow flowers in the spring, followed by seed pods. Allow the pods to mature fully on the plant; they’ll turn from green to brown and become dry, which is a sign they’re ready for harvest. This usually occurs in late spring to early summer.

Harvesting Seeds

When the seed pods have dried on the plant, cut the stalks to prevent them from splitting and dropping seeds. Take the stalks indoors and allow them to fully dry in a warm, well-ventilated area for one to two weeks. Once the pods are completely dry, gently crush them over a bowl or container to release the seeds.

Cleaning and Storing Seeds

After separating the seeds from the pods, remove any remaining plant debris. Place the cleaned seeds in an airtight container, labeling it with the kale variety and harvest date. Store the seeds in a cool, dry, and dark place, such as a pantry or drawer. When stored properly, kale seeds remain viable for up to five years, providing a long-lasting seed supply for future planting.

Benefits of Seed Saving

Saving seeds from heirloom kale contributes to sustainable gardening, reduces seed costs, and ensures the preservation of unique kale varieties that may be well-adapted to your local climate. By saving seeds from healthy, robust plants, you’re also naturally selecting for traits like disease resistance and high productivity, resulting in a stronger garden over time.

Saving heirloom kale seeds allows you to become part of a tradition of preserving valuable plant genetics, giving you access to nutritious, reliable greens season after season.

Conclusion

This Heirloom Kale Planting Guide offers everything you need to know about how to grow heirloom kale and enjoy a rewarding garden experience. By cultivating heirloom kale, you’ll be nurturing a crop that is not only nutritious and delicious but also rich in heritage and genetic diversity. Whether you’re new to gardening or experienced, planting heirloom kale brings immense satisfaction, vibrant greens, and healthful flavors straight to your table.

FAQ: Heirloom Kale Planting Guide: From Seed to Harvest