Guide to Blanching in the Vegetable Garden
By Steven Biggs
How to Blanch Celery, Cauliflower, and Other Vegetables
One word, two meanings!
For many people, blanching vegetables means a quick dip in boiling water before freezing them. This type of blanching slows down or stops the enzymes that cause colour and flavour loss.
But there’s another type of blanching, and it’s something that we do right in the garden.
Blanching in the garden refers to covering up part of all of a plant to exclude light. Without light, it grows differently.
The result is a milder tasting and more tender crop.
Keep reading to find out what crops you can blanch—and how to do it.
Common Crops
These are crops that are commonly blanched in the garden. You can grow them without blanching, but blanching improves the quality.
Asparagus
Cardoon
Cauliflower
Celery
Endive and Escarole
Leek
Rhubarb
Different Ways to Blanch
Soil hilled up along a row of leek plants.
Depending on what you’re growing, and how you want to grow it, there are a few ways to blanch vegetables in the garden.
Remember, blanching just means excluding sunlight. Here are some ways to do it:
Cover the plant (e.g. inverted pots)
Hill the plant with soil
Wrap something around the plant (e.g. cardboard or newspaper)
How Long?
The plants are blanched for a few days to weeks before harvest – not the entire life of the plant.
Crop Blanching Tips
Asparagus
If you’ve ever seen white asparagus, these are spears that have been blanched by hilling with soil. It’s a delicacy in Europe, less common in North America.
Cardoon
Blanching cardoon plants by wrapping them in fabric.
I’ve heard of people growing cardoon in a trench…but it’s a pretty big plant needing a pretty big trench. Instead, wrap mature plants 2-3 weeks before harvest, leaving the top of the older leaves exposed, but the base covered. The idea is that the inner leaves are white and tender. Some people use cardboard, but I think the most elegant cardoon blanching I’ve seen was burlap coffee sacks.
Cauliflower
With cauliflower we blanch the head. White-headed cauliflower is blanched to keep it bright white. It is still edible if you don’t blanch it…but can develop a yellow or green tinge, and get a stronger flavour.
Blanching cauliflower by tying together leaves to cover the head.
As the developing heads begin to expand, tie leaves around them to keep out the light. Don’t wrap the leaves too tightly over the small head as it will need space to expand. I’ve heard of people using paper bags, but if there are leaves there, it’s easier and less wasteful.
There are also “self-blanching” types of cauliflower, with leaves that naturally grow around the developing head. Some of these varieties still benefit from additional wrapping.
Celery
With celery we blanch stalks for 2-3 weeks leading up to harvest, keeping the leaves at the top exposed. Blanching helps reduce bitterness and lighten the stalk colour.
Blanching celery with waxed milk cartons that have the top and bottom cut out.
As with cauliflower, there are also “self-blanching” celery types. These have a lighter colour and milder flavour.
Hilling soil around the stalks is one way to blanch celery. Grow celery in a trench, and then gradually fill in the trench with soil leading up to harvest. If you use soil, first wrap the stalks with newspaper, so you don’t get lots of soil between the stalks.
You can also blanch celery by tying paper around the stalks, covering with waxed cardboard milk cartons or tall narrow tins that have both ends removed, or surround the stalks with boards.
Blanching celery plants with boards.
Grow a Container Vegetable Garden
And get an early harvest of crops that usually take too long!
Endive and Escarole
A board propped up over a row of endive or escarole is an easy way to blanch it.
Many people grow endive and escarole for the bitter taste. But you can blanch them to reduce the bitterness. Cover entire plants for a week before harvesting.
For individual plants, cover with a clay pot or a paper bag. For a whole row of plants, place a board over the row.
Leek
The base of leek plants can be blanched to give tender white flesh. In late summer, hill the base of the plant with soil, or wrap to exclude light. As with celery, leeks can also be grown in a trench that is gradually filled in as the plant gets taller.
Rhubarb
Blanch rhubarb by cover up plants with an inverted bushel basket as they begin to grow in spring.
When rhubarb is blanched it produces tender, elongated stalks that have a bright pink-red colour.
To blanch rhubarb, put an inverted bushel basket over the plant in the spring, as it begins to grow.
Why Not Blanche a Weed!
While a weed for many, dandelions are a kitchen staple for others. Our springtime menu includes dandelion frittata or a mixed salad with dandelion leaf pieces.
But dandelion, like its kin in the chicory clan, can be very bitter. The solution is to blanch dandelion. Simply cover with an inverted clay pot or a board – and you’ll be rewarded with tender, translucent, and mild-tasting leaves.
Blanching Challenges
Blanch dandelion by covering with an inverted pot or a board.
Blanching is easy to do. The biggest challenge is remembering to do it in time.
Another challenge is lightweight covers that blow away on windy days. If you use terracotta pots, they’re heavy enough to stay in place. But plastic coverings can blow away. The solution is to weigh them down with a brick or rock.
Top Blanching Tip
Put a note on your calendar to remind you to blanch your crops ahead of time.
Garden Blanching FAQ
Is Blanching Optional?
You don’t have to blanch these vegetables to eat them. But blanching gives a milder tasting, more tender, and more attractive vegetable.
What is “Self-Blanching?”
Some varieties don’t need help from gardeners with blanching. For example, with cauliflower, self-blanching varieties have leaves that grow to cover the head. Self-blanching celery has stalks with a mild flavour that don’t require blanching.
Why Grow Varieties that are not Self-Blanching?
You might be wondering why bother growing varieties that need blanching when self-blanching varieties are available. As you choose varieties, self-blanching is one trait to consider, along with other things such as having different harvest windows, price, and availability.
