Harvesting kale: how to harvest, store & preserve kale

Edward
Edward
Edward
Edward

With a passion for growing installed at an early age, I have always been happiest outdoors in nature. After training as a professional gardener and horticultural therapist, I currently run horticultural therapy and community kitchen gardens in the UK, helping others access the many physical and mental health benefits of growing vegetables, fruit and plants.

Favourite fruit: apples and pears
Favourite vegetable: asparagus

With the right care, kale plants can produce impressive yields. Learn how to harvest kale and how to store it if you have a bumper harvest.

Green foliage of kale plants
Kale is not only tasty but highly nutritious as well [Photo: Amverlly/ Shutterstock.com]

With its health benefits and superfood status, it is no surprise that kale (Brassica oleracea Acephala Group) has recently grown in popularity. Generally, you can pick kale as and when you need it. However, if you end up with a glut of its luscious leaves, there are ways of storing and preserving kale.

Harvesting kale: when and how

If you are wondering when to harvest kale, the harvesting period is generally from September until April. However, you can pick the leaves anytime depending on how you want to use them. As a hardy crop that can withstand temperatures as low as -10 to -15 °C, you do not need to pick the leaves before the winter arrives. In fact, it is quite the opposite with kale, as it is said that the leaves develop a sweeter taste once there has been a frost, as the bitter compounds in the foliage decrease with the cold.

With the foliage ranging in colour from green to red, there is an array of different kale varieties available to grow. To harvest kale, you can either pick a few kale leaves when they are young to use in salads or allow the plants to mature and harvest the larger leaves from autumn to cook with. Either way, it is best to only pick a few leaves at a time rather than stripping the plants bare so that the plants can continue to photosynthesise. When it comes to how to harvest kale, you can either cut or pinch the leaves off the stems, starting with the sides shoots first as new growth develops from the centre.

How to preserve and store kale

The health benefits of kale are widely recognised, but the nutrients can decrease when cooking kale and storing it. Freshly harvested young kale leaves are perhaps most wholesome when eaten raw and are best eaten straight away. However, larger kale leaves are tougher and will keep fresh for up to a week when placed in a bag in a refrigerator. Nevertheless, there are also different methods of preserving and storing kale for many months.

A basket of green kale
You can harvest kale leaves when they are young or mature depending on their use [Photo: Elena Shashkina/ Shutterstock.com]

Can you freeze kale?

If you are unsure whether you can freeze kale, the answer is most definitely yes. To freeze kale, wash and cut the leaves into desired size pieces. You can either keep the stems or remove them. Blanch the kale by placing the pieces in a pot of boiling water for 1 to 2 minutes before removing and plunging the kale into a bowl of ice-cold water to stop the cooking process. Blanching kale is not strictly required but doing so can help remove any bitter taste and allow the kale to be kept frozen for longer. Once blanched, dry the kale and freeze it in a single layer on a tray for 1 to 2 hours. Once frozen, place the kale in bags to keep in the freezer for up to 8 months. Freezing kale has many benefits, you can simply add it to a pasta dish, soup or stew, or even blend it in a smoothie.

Washing kale in a bowl
Kale can be frozen for several months after blanching [Photo: casanisa/ Shutterstock.com]

Making kale pesto

Making kale pesto is a great way of adding kale to your diet and particularly for any fussy younger eaters. Once made, kale pesto will keep for a week in the fridge or up to a month in the freezer and is ideal for adding to pasta or using as a garnish. To make a pesto you can follow our kale recipe below:

Kale pesto recipe

Ingredients: 200g kale, 100ml olive oil, 1 clove of garlic, 1 pinch of salt, 1 tsp pepper, 1 tbsp lemon juice, 100g sunflower seeds, 85g parmesan (optional).

  • Slice the kale into small pieces and boil for 3 to 4 minutes
  • Allow the kale to cool
  • Add the kale and other ingredients to a food processor and blend until smooth
  • Use straight away or spoon into a sterilised jar and top up with olive oil before sealing
  • Keep in the refrigerator or freezer
Kale pesto in glass jar
Kale is ideal for making pesto [Photo: Elena Veselova/ Shutterstock.com]

Making kale chips

Another method of preserving kale is to make it into chips. Kale chips are perfect for a healthy snack but being so delicious they might not last that long. To make kale chips, wash and chop the leaves before patting them completely dry using a paper towel. Lightly season the kale with olive oil, salt and pepper. Place on a baking tray or in a dehydrator in a single layer. Bake in an oven set to 150 °C for around 20 minutes or a dehydrator at around 40 °C for 6 to 8 hours. Allow to cool and either enjoy straight away or seal in an airtight container for up to 2 to 3 days.

Kale chips on baking tray
Kale chips are a tasty and healthy snack [Photo: Fascinadora/ Shutterstock.com]

Boiling and canning kale

For longer storage periods you can also boil and can your kale. To preserve kale by canning, cut the kale into pieces and either boil or steam it for 4 to 5 minutes. Once the kale is cooked, spoon it into a sterilised jar and cover it with freshly boiled water, leaving a 2 to 3cm gap at the top. Seal the jar with a sterilised lid and place it in a pressure canner for the allotted time. Once canned, your kale can be kept for up to 1 year in a cool and dark place. However, if the lid begins to bulge the kale may not be safe to eat and should be discarded.

Fermenting kale

With fermented produce becoming more popular, you can also preserve kale by fermenting it or making kale kimchi. To ferment kale, cut it into slices and wash thoroughly. Add the cut kale to a large bowl and sprinkle a good pinch of salt and some pre-chopped garlic and onions over the kale before massaging the ingredients into the kale and allowing it to rest at room temperature for around 2 hours. Add the kale mixture including the liquid produced to a sterilised jar and top up with a brine solution so that the ingredients are covered. Seal the jar and place it in a dark cupboard at around 18 °C for 7 to 10 days, removing the lid every 2 to 3 days to allow the gas build-up to escape. Once the fermented kale has reached the desired taste, you can keep it in the fridge for 1 to 2 weeks to enjoy as you wish.

Kale and cabbage fermenting mixture
You can ferment kale on its own or with cabbage [Photo: Lyudmila Mikhailovskaya/ Shutterstock.com]

As a tough and hardy vegetable, kale generally grows trouble-free. However, for some tips and tricks on planting kale, check out our separate article.

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