The Best Fertilizer for Kale: A Home Garden Growing Guide

Kale is one of the easiest leafy greens to grow. There are many varieties, making kale a versatile vegetable. We’re going to show you the best fertilizer for kale in your home vegetable garden.

What is the Best Fertilizer for Kale?

With so many different products on the shelf, it’s hard to know what’s the right one for your plants. We’re going to explore your options for kale and other leafy greens in your garden.

But First, What is Kale Anyway?

Kale is known to have derived from brassica oleracea, as a member of the cabbage family like many other greens. The leaves are high in vitamin C, calcium, and other essential nutrients making kale a healthy staple to add to the home garden.

What Helps Kale Grow?

Cool soil temperatures and high nitrogen are best for growing kale just like many other leafy greens. Avoiding clay or rocky soils will help your kale plants grow strong roots. Amending your soil with organic matter is a great way to help your kale thrive.

When to Plant, Grow, and Harvest Kale

Many gardeners like to grow kale varieties in the early Summer or as a Fall crop. However, kale leaves gain a little sweetness during the cool season, so the best time to grow them is during the late Fall or Winter months. Kale leaves taste even better when they’ve been kissed by a light frost.

Soil, Planting, and Care

Clay soils or rocky soils will prevent your kale plants from growing strong roots. You can amend your garden soil with organic matter to help your plants thrive.

Garden Bed Preparation

Obtaining a soil test is not a bad idea as you prepare your garden beds for planting. Make sure that you’ve chosen an area with well-drained soil. I like to top my beds with a 2 inch layer of compost before planting so that I start with a fertile soil.

How to Plant

Purchase started plants from a reputable nursery in your area to save time, or start your own seeds to save money. Check out our FREE Ultimate Seed Starting Guide to help fast track your success in the garden.

• Planting Kale – In late Summer, start with a quality soil, and scruff up the surface with a tool or your hands. Sprinkle kale seeds and cover them over with about 1/4 inch of soil. You can direct sow seeds to your garden beds or sow them in pots to transplant later.
• Transplanting Kale – Water your kale seedlings well and gently remove them from the pots they were started in. Dig a hole in your garden or container that fits the entire root ball. Do not bury the plant’s stem too deep.

How to Get the Best Yield

Space your plants to 18-24 inches apart. If you overseeded them, make sure that you thin plants as they germinate to give plenty of space. Maintain a cool moist soil, and feed them with fertilizer.

Which NPK Ratio to Choose?

All commercially-sold fertilizers are going to show you the nitrogen, phosphorous, and potassium content of the material. This is known as the NPK.

What Nutrients Does Kale Need to Grow?

Many people choose to use a balanced fertilizer, such as a 10-10-10. Since kale is a heavy feeder, I tend to give them a little more nitrogen during the growing season.

So, What is the Best Fertilizer for Kale afterall?

You could start with a slow-release fertilizer like compost. Sprinkling a granular fertilizer at the base of the plant will offer a continuous, long-lasting feed. Alternatively, you could apply a weekly liquid fertilizer. Whichever you choose, look for a quality organic fertilizer.

What are the Advantages of Fertilizing Kale?

Fertilizing kale helps promote full size plant growth. It also ensures proper mineralization to the plant, giving you nutrient-rich leaves and better flavor. You’ll have much smaller, slower-growing kale plants if you choose not to fertilize them.

Kale Fertilizer: What To Look For

A higher nitrogen fertilizer is most often needed for leafy green vegetables. Check that NPK reading on the package label. The first number (nitrogen) should be higher than the second and third numbers.

What is the Best Nitrogen Fertilizer for Kale?

Choosing an organic, high nitrogen type of fertilizer, like composted chicken manure, will be best for your kale. The first number in the NPK sequence correlates to the nitrogen (N) content, so I look for something with a higher first number.

Why Choose Organic Fertilizer?

Choosing organic fertilizers is beneficial to the plants and to those who eat them. Petroleum-based fertilizers contain carcinogens that we don’t want on our food. They also disrupt the microbiome of the soil. Plants will be weakened and easily succumb to pest and disease pressure over time.

A Variety of Organic Fertilizers to Choose From

Vegan growers may choose to use composted greens and plants, while conventional growers have more options such as:

• Composted manures like chicken, cow, and horse manures
• Cold manures like rabbit, goat, and sheep manures
• Blood meal
• Feather meal
• Bone meal
• Fish emulsion
• Compost
• Worm castings

If using composted animal manures, make sure that the animals weren’t fed grasses or hays that were sprayed with long-term, persistent herbicides like aminopyralid.

Homemade Fertilizer for Kale

A great option for homemade fertilizer for all of your plants is by using a liquid compost tea. Grab a bucket with a lid. Dump some kitchen vegetable scraps and plant matter into the bucket, filling it about half way. Now fill the bucket with water and cover it with the lid. After about 10 days, pour the liquid around your kale plants. Check out David The Good’s “fetid swamp water” tutorial for more info.

When is the Best Time to Fertilize Kale?

Apply fertilizers early in the morning or late in the evening along the side of the plant.

How Often to Fertilize Kale

It’s really only necessary to fertilize kale plants once or twice during the growing season. Liquid fertilizers only last a week or so. If you’re getting a lot of rain, you may need to apply fertilizers more often

Best Fertilizer for Kale in Pots

Kale planted in pots or containers will need fertilizer applied more often because they are watered more often. You can use the same fertilizers that we’ve recommended for in ground gardens above.

Kale Plant Care

Harvesting any leafy green vegetable takes:

• quality fertilizer
• proper sunlight
• good drainage
• protection from weed growth
• relief from pest and disease pressure
• healthy soil
• proper watering

Harvest and Storage

The best way to harvest kale is to cut the outer leaves from the mature plant. Rinse them well and pat dry them. You can store them in a plastic bag in the refrigerator until you’re ready to use them.

Insect & Disease Problems

Many pests enjoy munching on kale in our home gardens as much as we do. Flea beetles and cabbage loopers are two of the main culprits, but cut worms will take off the smaller, tender leaves too. Kale is pretty hardy and you can organically treat plants with insecticidal soaps or bacillus thuringiensis (BT). Read our post about using Natural Pest Controls for Your Garden for more ideas on combatting insects.

Downy mildew and other fungal diseases can be a problem during hot Summers or early Spring if your area experiences a warm, wet season. The best method for treating this problem is to spray the leaves with neem oil.

Growing Kale: How To Get Great Greens Harvests

Make sure that you harvest the larger leaves from mature plants. The young plants need all of their leaves for proper photosynthesis. Make sure you’re growing kale plants in optimal conditions.

Sun and Temperature

Kale grows best in full sun but will tolerate partial shade too. For best results, plant them in a place with at least six hours of sunlight. Attempting to grow kale during the hottest part of the year will result in wilted plants, heavy pest pressure, and little harvest.

Water and Humidity

Kale needs plenty of water to grow those lush green leaves that we love. I like to see if the soil is moist enough by poking a finger into a couple of inches of soil. If it’s dry underneath, then give plants about an inch of water, or until you see the water soak into the ground around the plants.

Soil

Be sure that your soil is cool, moist, and full of life. Creeping bugs and worms in the soil is usually a good sign that you have healthy soil.

If your soil is too dry, too rocky, too sandy, or has too much clay, adding plenty of compost will always help.

Pruning Kale

Kale plants can easily tolerate cold temperatures, but sometimes, extra hard frosts and freezes can damage some of the top leaves. Likewise, hot temperatures may burn some of the top leaves. Simply cut them off at the stalk.

If you have forgotten to harvest kale in a while, the bottom leaves will begin to wilt and brown. It’s important to cut those off too.

How to Save Seeds

During the warm temperatures, kale plants will flower and set seeds. Once the flowers have dried, the plant will produce little green, elongated pods. The seeds are inside of those pods. These pods are edible, and make a tasty addition to salads.

Or you can allow the pods to dry on the plant, pluck them, and break them open to find little black seeds. Save dried seeds in a paper envelope and store them in a cool, dry place to plant next year.

Recommended Kale Varieties

We like these varieties of kale for different reasons.

• Curly Kales: adds a wonder texture to salads. Examples are Red Russian and Curly Kale
• Flat Leaf Kale: good for dehydrating into kale chips or sauteing. Examples are Russian or Portuguese kales.
• Dinosaur Kale: A long, flat leaf kale with a mild flavor, good raw or cooked. Tolerates warm temperatures better than others. Grows into tall plants. Also known as Lacinato kale or Tuscan Kale.
• Ornamental Kale: typically used to garnish plates or salad bars. Comes in many hues of green and purple. Grown for its beauty and often worked into landscaping and flower beds.

Kale is a super simple plant to grow even for the first year gardener. By following our tips on kale care and using the appropriate growing conditions, you should have no trouble successfully growing one of the most nutritious vegetables in your garden.

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