Kale Growing Guide

Kale is one of the most delicious and nutritious vegetables you can grow easily in your garden. This green leafy vegetable contains vitamins A, C, and K, minerals (like Fe), and vital antioxidants. This quick-growing crop is harvested multiple times throughout the growing season. You can use their young green edible leaves in salads, soups, smoothies, or baked into chips. From choosing the right variety to harvesting and using your homegrown kale, this growing guide will discuss each step in detail. Keep reading to learn the expert tips about growing kale.

Kale: A Quick Overview

Kale (Brassica oleracea ) is a hardy, versatile, and non-heading green-leafy vegetable. It belongs to the Brassica family, which includes broccoli, Brussels sprouts, and cabbage. This resilient cool-season crop grows well in spring and fall and tolerates frost and snow.

Kale's leaf grows outward from a central stem, so you can harvest multiple harvests by cutting what you need and letting it grow back. Its leaves can be ruffled, flat, or frilly, resembling dinosaur skin. These plants can grow up to 3 feet (90 cm) tall. However, the dwarf varieties are available for smaller spaces.

Kale plants are also considered ornamental, with curly and textured leaves in purple, dark red, and deep bluish-green shades. Their ornamental appeal and nutritious value make them a perfect addition to garden beds or containers.

Kale is a biennial plant that produces leaves in its first year of growth. Then, in the next year (or sometimes later in the first year), it forms a flower stalk. This stalk blooms produces seeds, and then the plant dies.

Choose the Right Kale Variety

There are many types of kale, each with its unique texture and flavor. You can grow different varieties to see which ones you like, and which do best in your climate. Growing your kale also lets you try varieties you can't find at the grocery store. Here are some common kale varieties.

Curly Leaf Kale

This heirloom variety has light to medium-green leaves with deep frills. It is cold-resistant and commonly found in grocery stores. These prolific, compact plants include varieties like Dwarf Blue, Winterbor, Redbor, and Blue Curled Scotch. It has a slightly bitter flavor that softens when cooked.

Dinosaur Kale

Also known as Toscano kale and lacinato kale, this Italian kale variety has long, dark, bluish-green leaves. The rough, scale-like appearance of the leaves has given it the nickname dinosaur kale or dino kale. Its leaves can grow up to 2 feet and resemble mini palm trees. Toscano kale is heat-tolerant and cold-hardy. They are great for making kale chips.

Red Russian Kale

This heirloom cultivar has flat, fringed leaves, reddish-purple stems, and a sweet flavor. It is also known as an early crop. Their young leaves are great in salads. However, this plant is more susceptible to pests than other kale varieties.

Siberian Kale

This plant type has large, frilly, blue-green leaves and is extremely cold-hardy. In some regions, you can pick leaves all winter.

Ornamental Kale

This kale type has colorful leaves, white and deep purple, and is commonly used for decorative purposes. They have poof, showy heads in pink and cream color. These plants are great for making borders or adding colors to rock gardens.

Prepare Your Garden

After choosing the best kale variety, the next step is to select a location and prepare your garden for plantation.

Select Kale Plantation Site

Kale grows well in direct sunlight but can tolerate partial shade. Choose a location that receives at least six hours of sunlight per day. It grows well in raised beds, garden soil, pots, and containers. If there is enough light, you can also grow it indoors. Kale grows best in window boxes that face south or west. In hotter climates, east-oriented windows can help protect against scorching afternoon sun. Excessive heat may cause the leaves to wilt and lose flavor.

Soil Requirement and Preparation

Like collards, kale grows best in fertile and well-drained soil. If your soil has poor drainage, grow kale in raised beds or mounded rows. The soil pH should be 6.5 to 6.8 to prevent clubroot disease. If clubroot is not a problem in your garden, kale can grow at a pH of 6.2-6.8.

Before planting, till or spade the soil to a depth of 12-15 inches using a Garden Spade. If the soil is not fertile, add nitrogen additions like composted manure, cottonseed meal, and blood meal, or mix in a few inches of Organic Nutrients Insect Frass.

Spacing Requirements

Plant seeds 1 inch apart and 1/4 to 1/2 inch deep, spacing rows 18 to 30 inches apart. When planting young kale transplants, place them at the same depth as in containers. Space them 12 inches apart in rows about 18 to 30 inches apart.

Best Growing Zones for Kale

Kale is a cool-season crop that can be cultivated in USDA hardiness zones 2-9. It grows best in temperatures below 75°F. Young kale plants can survive temperatures as low as 25°F, while mature plants are hardy and can tolerate extremely cold temperatures.

When to Plant Kale

Whether you're directly sowing kale seeds or transplanting seedlings, plant them 3 to 5 weeks before the last spring frost in your area. Select early maturing kale varieties for fall harvest and plant them 6 to 8 weeks before the first fall frost date.

In mild winter regions (zones 7-9) such as the Pacific Northwest, Southeast, and Southwest, kale can be planted as a winter crop under covers or outside. In these areas, kale grows and yields throughout the winter. You can also leave kale plants in the garden all winter to get out-of-season greens.

In warmer climates (zone 8 or above), plant kale in the fall or early spring to protect against summer heat. High summer temperatures can stunt growth, decrease quality, and cause leaves to develop bitter or unpleasant flavors.

How to Plant Kale

Kale is usually planted in a seedbed away from the main veggie garden and then transplanted to its final growing site with broader spacing. It grows slowly and takes up a lot of space during its prime growing period. However, you can also grow it directly in your garden.

Growing Kale from Seeds

Growing kale seeds is easy and requires no special treatment before sowing. You can either sow them outdoors directly in the garden or start them indoors and move them outdoors later. Here's how to do it.

Sowing Seeds Indoors

Fill seed trays or pots with soil starter pellets or high-quality seed-raising mix.
Sow kale seeds about six weeks before your area's expected frost date.
Cover the seeds with about 1/2 inch of soil.
Keep the growing medium consistently moist.
Once the danger of frost has passed, transplant your seedlings to the planting site.

Sowing Seeds Outdoor

You can plant kale seeds directly in the garden as the soil temperature reaches 45°F.
Sow the seeds about 1/2 inch deep in the soil
Keep the soil moist for quick germination, which may take five to 8 days.

Growing in Pots

If you don't have a garden or suitable soil conditions, you can grow kale in pots or containers. This method allows you to move the plant for optimal sunlight and protection from severe weather.

Choose a pot with at least a 12-inch diameter and adequate drainage holes. Our Smart Pot fabric growing container is ideal, allowing excess moisture to escape and preventing root rot.
Use a high-quality potting mix; an organic mix formulated for vegetables is a great choice.
Transplant your kale at the same depth as in its previous container.
Water the plant well after planting.

By following these steps, you can successfully grow healthy kale in pots.

Transplanting

Transplant young kale plants from their sowing site to their growing site when they have at least two sets of true leaves and are about 4-6 inches tall.
Water the young kale plants well the day before transplanting.
Firmly compact the soil to stabilize the kale plants, especially against winter winds.
Carefully lift the young plants without disturbing the roots and place them in their new planting site. Make sure the lowest leaves are at ground level.
Space plants 12-18 inches apart in rows spaced 18-24 inches apart.
Water generously to settle the roots.

Kale Plant Care

Watering

Kale requires consistent moisture to grow, so water deeply, but avoid making it soggy. Cold temperatures and moist soil make kale leaves sweet and crisp. Provide 1 to 1.5 inches of water per week, about 1 gallon per square foot. Avoid overhead watering to reduce the risk of disease.

Consider using drip irrigation or a soaker hose to minimize water usage and direct water to the soil. Install our drip irrigation according to your plant spacing. Position the drip lines or emitters along the row of kale plants. Set the watering schedule (1-1.5 inches per week) and regularly monitor the soil moisture level. Applying mulch around the plants helps retain soil moisture and suppress weed growth.

Fertilizing

Before planting, enrich the soil with compost and a mild, slow-release granular fertilizer. After four weeks of thinning or transplanting, apply 1/2 cup of nitrogen-based fertilizer (30-10-10) every 10 feet of row to boost growth and increase harvest. Place the fertilizer 6 inches to the side of the plants and water it into the soil.

How to Harvest Kale

Harvest kale when the leaves are about the size of your hand and the stalks are 10-15cm (4-6in) long. If you want to harvest young kale leaves for salads, you have to wait 25-30 days: for mature leaves, 50-75 days.

You can pick individual leaves from multiple plants or cut the whole bunch from a plant, as it will re-sprout to provide another harvest.

Start harvesting by picking the oldest leaves from the lower portion of the plants. Work your way up the stalk, taking as many leaves as you want while leaving at least four intact at the top of each plant. Avoid picking the terminal bud in the plant's top center, as it helps to maintain productivity.

Kale will continue to grow until temperatures fall below 20°F (-7°C). Don't stop harvesting; a mild frost might increase the sweetness. In milder climates (zones 7 to 10), kale will continue producing new leaves throughout the winter. In colder regions, provide extra protection with row covers, plastic tunnels, and mulch.

Storage

Wash kale leaves thoroughly under cool running water to remove soil and pests. Pat dry with a clean towel or use a salad spinner. After drying the leaves, store them in a plastic bag in the refrigerator for up to 2 weeks at 32°F and 95% relative humidity.

Usage

Use the small, delicate kale leaves raw in salads or smoothies. If you find kale too crunchy or dry, massage the leaves with olive oil to soften them. For mature leaves, cook them like spinach after removing the tough ribs. Add chopped kale to soups and stews or cook in kale chips. Kale is a spinach substitute in various dishes like omelets, quesadillas, and casseroles.

Common Diseases and Care

Kale is susceptible to various pests and diseases. Here are some common problems and how to control them.

Aphids: These tiny, sap-sucking insects cluster on leaves and cause them to curl and wrinkle. Use suitable insecticides or insecticidal soaps. Spread bananas or orange peels around the plants.

Cabbage Worms: These green worms chew holes in leaves and hide in kale leaves. Leaves have large, ragged holes. Use Bacillus thuringiensis (Bt) to control the worms or handpick them. Grow companion plants, like thyme.

Black Rot: This fungal disease causes yellow, V-shaped spots on leaf edges that move toward the leaf center. As a result, leaves collapse, and stem segments show blackened veins. Choose resistant varieties and provide good drainage. Practice crop rotation and remove infected plants to control this disease.

Flea Beetles: These small black beetles feed on seedlings. Adults chew tiny holes in leaves and cotyledons, reducing plant stands or killing seedlings. Use row covers, insecticidal soap, and mulch.

Final Takeaway

There you have it - a comprehensive and easy guide for growing kale. Kale is a resilient and productive crop that can grow in different soil conditions and climates. By following this simple guide, you'll soon be harvesting fresh kale leaves in your garden. You'll become an expert in your kale garden in no time. So why wait for frost? Put your gardening gloves on and start growing your own kale today.

FAQs

For how long can I harvest kale?

You can harvest kale for several months. Spring-planted kale can be picked all summer, but the leaves might get tough and bitter due to heat. In the fall, the quality of leaves improves again. Kale grows all winter in mild, colder climates, and frost makes its leaves sweeter. Fall-planted kale also follows the same pattern.

How Long Can I Store Harvested Kale Leaves?

Kale leaves stay fresh in the refrigerator for up to 2 weeks. To maintain freshness, store them in an unsealed plastic bag with a damp towel.

What Should I Do If My Kale Bolts?

Bolting occurs when kale plants start to flower and produce seeds. This usually happens in the second year for biennial plants or during extreme heat. Once bolting starts, the leaves may become bitter. Harvest any remaining leaves, remove the plant, and replace it with a new crop.