How to Grow Kale: Ultimate Guide for Home Gardeners

Learning how to grow kale means you'll be eating greens rich in way more vitamins than salad bar varieties. Your leaves are on the plate within hours of harvesting, preserving nutrients like vitamin K and antioxidants in their full glory. Freshness matters for flavor, too.

You can have kale at your command throughout the year by successional planting. In very warm climates, I believe it is possible to have it for most of the year, at least. The plants stand out all winter, even under snow in the coldest regions. I gathered the sweetened leaves during a thaw in January from my winter garden.

No matter how much you garden, kale is for you. We adapt well to pots and patches, so start with a few plants, and before long, you'll see why we're called "Superfood" in an instant.

Using Kale in Recipes

Rub raw kale leaves for salads. Rubbing kale leaves makes them more palatable. Rub the picked greens thoroughly for three minutes, sprinkling with olive oil and salt. The olive oil and salt will dissolve, and the fibre will be broken down until the greens become tender and sweet, resulting in a palatable salad without any cooking.

For crispy kale chips, bake at 300°F (150°C) for 15 minutes. First, toss your torn leaves lightly with oil. Oversee them so they don't burn. I turn the pans halfway through to ensure even crispness.

You may freeze kale by pre-blanching it. To do this, place the leaves in boiling water for exactly two minutes, then immediately transfer them to an ice water bath after removing them from the boiling water. Drain thoroughly and pack in Air-tight containers. This will preserve the color, nutrient value, and flavor.

Preserve vegetable stock stems, but use them accordingly. Finely chop the stems and simmer with onions and carrots. They add fiber to the stock, but can also introduce bitterness. Try to limit the quantity to one cup per quart of liquid.

Overwintering Kale

Kale can tolerate cold down to 20°F (-7°C) without any protection. Plants established for over 8 weeks can better tolerate the cold than seedlings. I have harvested from plants that survived a light snowfall, while younger plants did not survive.

Put down 8 inches (20 cm) of straw mulch around your plants before the first hard frost. This mulch will insulate the roots to below 15°F (-9°C). For extra protection, use row covers when lows are below 10°F (-12°C).

You can prune varieties under 4 inches (10 cm) of snow. With deeper snow, it is necessary to brush off the covering before picking it up. Frost-hardened leaves are sweeter than those growing in warmer environments due to sugar concentration. Plants that are over 12 weeks old are more frost-hardy.

Young kale requires protection at 25°F (-4°C), while mature kale can tolerate temperatures as low as 15°F (-9°C). On either side of a freeze event, always ensure kale has been watered, as hydrated cells will tolerate damage better. Once a good thaw starts in spring, remove mulch gradually to avoid rot.

Pest and Disease Management

Identify colonies of aphids that are larger than a dime before initiating treatment. Apply a soap solution for two or three consecutive treatments every three days after the temperature reaches 55-75°F (13-24°C). Ladybugs can be effective, but only when temperatures are above 60°F (16°C), and they can consume as many as 50 aphids per beetle per day.

Manage cabbage worms by handpicking when the temperature is above 50°F (10°C), and apply Bt spray subsequently every week until the outbreak is over. Companion planting is a magnificent tool, and you can place your nasturtiums a full 12 inches (30 cm) away to draw pests away from the planted kale.

Prevent downy mildew by spacing plants 18 inches (45 cm) apart for airflow. Apply copper fungicide every 14 days in humidity over 60% at 60-75°F (16-24°C). Remove infected leaves immediately.

Use diatomaceous earth against flea beetles after the rain dries. Reapply after every rainfall. Plant radish trap crops 10 feet (3 meters) away from the target area. Garlic chives planted 6 inches (15 cm) from kale deter multiple pests.

Planting Kale Step by Step

For indoor seed starts, plant your seeds ¼ in (0.6 cm) deep. Ideally, keep the seeds at a soil temperature of 65-75°F (18-24°C) until germination. I place my trays on seedling heat mats, which help keep them warm and evenly so they sprout in 5-7 days.

Direct sow outdoors when soil reaches 45°F (7°C). Bury seeds ½ inch (1.3 cm) deep in rows 18-24 inches (45-60 cm) apart. Thin seedlings to 12 inches (30 cm) spacing once true leaves develop.

Harden off indoor seedlings over 7 days before transplanting. Start with 2 hours of outdoor exposure daily. Gradually increase to full days. This prevents shock when moving plants permanently outside.

For container planting, use pots at least 12 inches (30 cm) deep. Space plants 10 inches (25 cm) apart for healthy growth. Fill with quality potting mix enriched with compost.

Kale Care Essentials

Water kale with 1 to 1½cups (240 to 360ml) per plant weekly during the periods of growth; for larger gardens, give 1 gallon (3.8 litres) per square yard weekly. Water freely during a heat wave, omitting to wet the leaves to avoid mildew trouble.

Feed plants monthly with balanced 10-10-10 fertilizer while they are actively growing. Switch to a low-nitrogen 5-10-10 formula approximately six weeks before the first frost. I apply granular fertilizer in a ring 6 inches (15 cm) from stems, then water deeply.

Maintain soil pH between 6.5-6.8 for optimal growth. If the pH drops below 6.2, mix 1 cup (240 mL) of lime into the soil per plant. For alkaline soils with a pH above 7.0, add ½ cup (120 mL) of sulfur per plant.

Mature plants need a minimum of 6 hours of direct sunshine. Seedlings require at least 4 hours of morning sun during their establishment phase. For zone 8 and above, if temperatures exceed 85°F (29°C) in the afternoon, provide shade during that time. Containers should be rotated to ensure even exposure to sunlight.

Harvesting and Storing Kale

Harvest baby leaves when they reach 3-4 inches (7.6-10 cm) in length for salad use; mature leaves are ready when they are 8-10 inches (20-25 cm) long. Cut the outer leaves using sharp scissors, but leave the central bud intact. Morning yields crisper leaves with the nicest moisture content.

Store unwashed kale in breathable produce bags at 34-38°F (1-3°C). Put paper towels in the bags to absorb moisture for up to 14 days. For root cellaring, keep whole plants upright in damp sand boxes at 32-40°F (0-4°C).

You can freeze kale by blanching it for exactly 2 minutes in boiling water, and then putting it into the ice water. Be sure it is drained completely before packing in sealed containers. This maintains nutrients while freezing at 0°F (-18°C) for 10-12 months without loss in quality.

Use vacuum-sealed bags to store or freeze your herbs if you plan to use them over an extended period. Dehydrate your herbs at 125°F (52°C) until they are brittle, and then store them in glass jars at 65-75°F (18-24°C). Frost-hardened leaves will become sweeter while also reducing phytic acid, which makes them perfect for eating raw.

5 Common Myths

Conclusion

Kale is the most nutritious of all vegetables whether eaten sweet and tender in summer salads or stewed down in the winter: its vitamin content is about the same at all seasons; frozen kale contains practically all the nutrients, and thus gives us summer greens in winter. There is no green that will adapt itself so readily to all our meals.

New gardeners appreciate the resilience of kale. It withstands temperature fluctuations with ease and is easy to care for. After you get started with just a few plants, you will feel confident watching these hardy greens grow with just a little water and air - what could be easier!

Cut-and-come-again technique. Pick the outer leaves, leaving the center growing point intact. New leaves appear every ten days and keep the plant bearing for months. You get much more from each plant in less time.

You can preserve your harvest by freezing or dehydrating. Frozen kale lasts for a year, while dehydrated kale chips are a crunchy snack to enjoy. Fresh kale flavors will remain available even when your garden beds are covered in snow, thanks to these preservation techniques.

External Sources

Frequently Asked Questions