Kale has received a lot of hype in the last several years. In fact, it’s safe to say that kale has had something of a recent revolution in the foodie world. It has gained its popular reputation as a super food, diet craze, and a millennial generation obsession second only to avocados. But kale is more than just a garnish or the latest fad in the food industry. The luscious, distinct leaves, crispy textures, and seemingly endless varieties make kale a plant worthy of growing in any garden.

Best yet, growing kale is easy. As a cool weather crop, kale can grow and thrive during months of the year where the garden isn’t producing much. Some varieties can even survive even under a bed of snow. Plus, every part of the kale plant is edible. So even once the plant bolts (producing flowers and begins to make seeds) gardeners can continue to harvest leaves for meals and salads. Beautiful, yellow, edible flowers can even provide a dash of color to foods.

Growing Different Kale Varieties

There are 150 different varieties of kale out there. Each one has its own attributes, colors, tastes, and growing needs. Of these 150 varieties, there are 2 main forms (smooth and crinkly). We have grown both main forms here at our gardens, and had many wonderful successes.

Crinkly Kale

Probably the most popular form of crinkly kale is the Blue Curly Kale, and that’s the variety we’ve had great success with. Crinkly kale gets a lot of flack for its appearance as little more than an ornamental weed in restaurants. From 1990 to 2010, the largest buyer of kale was Pizza Hut, as they used it to line their salad bars in their restaurants. Pizza Hut used crinkly kale as an ornamental plant because of its ability to hold its shape and texture for long periods without water. It is precisely this attribute that gives crinkly kale leaves their classic crunch in salads and makes them excellent chips when baked or air fried.

Crinkly kale is by far the easiest to grow in winter or in cooler latitudes as it is extremely resistant to cold weather. In warmer latitudes, most crinkly kales can even grow all year round.

Smooth Kale

Far more delicate than its hardy cousins, smooth kales like the Portuguese kale we’ve grown are more akin to leaf lettuce than to the more popular varieties of crinkly kale. Smooth kale grows lighter green leaves that can get about 5 inches long. The leaves are less crunchy and can be rolled or wrapped in ways that firmer crinkly kale leaves can’t.

However, smooth kale varieties aren’t as cold hardy as other kale varieties. While they don’t perform as well in winter, they are much better at surviving the hot summer months that crinkly kale can’t handle.

Kale’s Growth Lifecycle

Kale, regardless of form or variety, is a biennial plant. That means that the plant completes one life cycle every 2 years. Most brassicas (broccoli, cauliflower, arugula, and even the invasive-to-the-United-States garlic mustard) are biennial.

Kale and these other brassicas spend their first year growing as a round rosette of tasty leaves and their second year sending up a stalk of flowers that mature into seeds. This second year of growth is called “bolting.”

Bolting and What it Means for Growing Kale

As mentioned above, the term “bolting” refers to plants with a biennial life-cycle that are in their second year of growth. At this point in their lives, Kale and other bolting plants, go to seed. When bolting, plants like kale grow a tall stalk which eventually forms flowers that become seeds.

Bolting occurs not just among brassicas like kale, broccoli, arugula, and others. Other plants that bolt include herbs (basil, cilantro, dill), root vegetables (onions, carrots, some radishes), and leafy greens (lettuce, spinach).

Most people think that the growing season is over when kale or other vegetables bolt, but that’s a myth. There is no need to pull your bolting plants from the garden. Bolting is a natural progression of the plant’s lifecycle and, depending on the plant, leaves and other plant parts can be edible and even tasty after bolting.

Why Kale Bolts in the First Year

I know, I can hear you now. “If bolting occurs in the second year of a biennial plant’s lifecycle, why does my kale (or insert other veg. here) bolt in the first year when I grow it in my garden?!” One simple answer: Impatience.

From a young age, we’re taught that seeds are sown in the spring and produce in the summer and autumn. This works a majority of the time, but it isn’t the full story. After a season of cold winter, we gardeners (myself included) are anxious to get out there, to plant and grow something! However, when we sow certain plants too early, we’re also waking them up too early when they should be asleep.

While it’s true that most kale and other biennials are fully capable of growing in the cold, planting them too early in the spring confuses them. Having produced a fair number of early-spring leaves, they then face hot weather when they’re supposed to be either asleep as seeds or making seeds themselves. Thinking they’re older than they are, plants like kale then grow their central stalk and begin to produce flowers for seeds.

Planting Kale

Because of their biennial nature, the ideal time to plant kale is in not in the spring but in the mid to late summer, depending on your latitude.

To know exactly when to plant your kale seeds, look up your area’s average temperatures in the autumn. Find the date in autumn when temperatures have a chance to drop below freezing (32 degrees Fahrenheit, 0 degrees Celsius). Then work your way backward on the calendar 3 to 4 weeks. Since most kale matures in 55 days or so, this will give your kale a wonderful head start as you head into the winter, and provide some wonderful salads before the days start to get cold enough to ritard growth.

Kale can and will survive well into the winter. In warmer growing areas, kale will do well even under a cover of snow. But in colder climates, it may be necessary to provide a little help with a frost cover.

Harvesting Kale

One of the worst thing a gardener can do when growing kale (aside from sowing too early in the year) is to let it get too old before starting to harvest it. Kale is happy to be munched on by animals or harvested by us for food. It helps the plant to produce more leaves for longer. Plan to start harvesting kale leaves after about 55 days. Your plants may still be small then, but a little harvest earlier will prime them for later and longer growth.

A kale plant that is left unharvested for too long will bolt earlier. Once it has enough nutrients stored to produce leaves, it will start to produce the hormone (gibberellins) which incites the plant to bolt. Harvesting the leaves as the plant is growing inspires it to produce more leaves.

Harvesting Before Bolting

The trick to harvesting kale leaves is to leave the central bud. Select the outer and lower-most leaves when harvesting. These are the leaves that will ultimately be left in shadow and wilt as the plant grows. So it’s prudent to clip them early anyway to avoid wasting the delicious leaves.

As the plant grows, it will lengthen this lower stalk and send nutrients to the next set of lower leaves. Once those leaves have reached the desired size (usually about 5 inches for most varieties), you can harvest those. The cycle can continue like this for the whole season.

In warmer climates, or if you place your kale under a frost cover (like I did), you can harvest your kale leaves all winter long! Kale grows slower in the lower levels of light received after the Persephone Period is over. But winter kale tastes even better than the kale harvested during the late summer and autumn. During the winter, because kale grows slower, the leaves tend to taste sweeter than when it grows quickly during its early days in the ground.

Harvesting After Bolting

As already mentioned, bolting is not the end of your kale harvest. But there are a couple things you should know about harvesting your kale plants after they’ve started to bolt.

You can cut away the top bolting part of the kale before it has a chance to flower. Once cut away, continue to harvest your leaves as you would if it hadn’t started to grow that flower stalk. If you do this, the lower leaves will be less bitter than if you’d left the kale to grow flowers. When harvesting those top stalks however, do NOT throw the stalks away! The top part of the undeveloped kale flowers are called kale raab, buds, or florets. They are entirely edible and tasty. Think of kale raab as a less dense broccoli, and you get the idea of what you’re eating. Brassicas are family, after all.

You can also allow the plant to go to flower and harvest the delicate blossoms themselves. The flowers are entirely edible. They add a delightful splash of color along with a subtle kale flavor to foods as garnishes.

Harvesting Seeds

If you’re looking to have a continual supply of kale seeds for your garden, don’t forget to set aside one or two plants for seeds for planting later in the year. You don’t need much, either. One kale plant will produce well over a hundred seeds for your garden.

But keep in mind that you’re not the only one who’s hoping for those seeds. Birds and other garden visitors will decimate the seeds you’re counting on for a late summer planting. You might throw some garden netting over those plants you’re saving for seed to deter unwanted creatures from foraging.

Grow Kale in Your Garden!

Growing kale is a wonderful way to have fresh to table leafy vegetables all year long. Kale can be used not just for salads. It’s wonderful steamed into vegetable stir fry, baked or air fried for kale chips, small wraps for tuna salads, or even pureed for smoothies. Kale is a superfood that you don’t need to spend top dollar to have in your diet. Buy your kale seeds once, grow plants for your table, and save seeds to plant a continuous supply!