How to Blanch Vegetables in the Garden

Using Coffee Cans to Blanch Vegetables

The Spruce / Marie Iannotti

You may be familiar with blanching in the kitchen, which means making vegetables tender by briefly cooking them in boiling water and then stopping the cooking process by plunging them into ice water.

In the garden, we blanch to stop the process of photosynthesis, which also keeps the plants tender and sweet. To do this, we need to cover part or all of the plant so that no sunlight gets in. Without the production of chlorophyll, the stems and leaves will become very pale and they won't develop the pungent flavor and tougher texture you would expect in a mature plant.

Vegetables to Blanch

Celery is the perfect example. The tender, juicy commercially grown celery that we are used to, is blanched. If you grow it at home without blanching, you will be taken aback by how much stronger the flavor is. You may prefer the strong taste, but if you are looking for something to match what you are used to, try blanching.

Other vegetables to try:

  • Asparagus: That's how they get the expensive "white asparagus".
  • Cabbage and cauliflower: Cauliflower and cabbage can be blanched by covering the heads with the outer leaves.
  • Chicory: Belgian endive is a chicory that is often grown indoors, in the dark.
  • Leeks: To get the maximum tender white ends, most leeks are blanched as they grow.
  • Lettuce: Blanching allows green, heading lettuce to maintain a sweet, tender heart. Many heads will self-blanch.

Blanching Methods

There are many clever ways of blanching vegetables. Let your creativity and convenience be your guide.

  •  Hilling soil: A traditional way to blanch leeks is to hill soil around the plants as they grow. You can use a hoe or shovel and periodically mound soil around the base of the plant. Some gardeners like to start by digging a trench and leaving the soil from the trench along the side of it. You plant in the bottom of the trench and gradually refill the trench with the soil, as the leeks grow. The only drawback to this method is that the leeks get filled with gritty soil and need a good cleaning, before eating.
  • Boards: This is one of the simplest blanching methods if you grow in rows. You will need at least 2 long 1 x 4 boards. When the plants are about 6 to 8 inches tall, you lean the boards on either side of the plants. The plants will still be able to expand and grow, between the boards. Keep an eye out for slugs and snails that like to hide under damp boards, in the garden.
  • Pots and other containers: This method is quick and easy if you only have a few plants to blanch. Any can or carton that is large enough to accommodate the plant at its mature size can be used. Remove the top and bottom of the container and slip it over the plant while it is still young. The plant will grow above the container, leafing out and blocking sunlight.
  • Growing in the dark: If you are growing plants indoors, you can simply grow them in a dark area. This isn't practical in most situations, but this method is often used for blanching endive and white asparagus.

You don't even need to blanch vegetables. There is nothing dangerous about eating any of these vegetables after they have been exposed to light. It is just an option, to obtain a flavor and texture that wouldn't occur naturally in the garden.