Asparagus: all about dual-purpose varieties

Let me start by explaining why asparagus is actually white in color. This is because it grows underground. Anyone who drives around in Brabant or Limburg during the asparagus season has surely seen them: large fields with narrow mounds covered in black plastic, the asparagus fields. And those mounds are there for a reason. They ensure that the asparagus stays nice and white. Because the asparagus never comes into contact with sunlight, it remains white. Plants produce chlorophyll under the influence of sunlight. But as long as the asparagus grows in the mounds of sand, it remains white. The foil ensures that the tips of the asparagus remain white as soon as they poke through the surface. This allows the asparagus harvesters to see from the bumps in the foil where an asparagus is ready to be harvested. Furthermore, the black color of the foil ensures that the soil warms up a bit faster, allowing the first asparagus to be harvested earlier in the season.

You now know that growing white asparagus requires some effort. A mound must be created around the asparagus to keep them underground and white. Green asparagus, on the other hand, is a lot simpler. They just grow above ground, turn green, and once you find them long enough, you break them off and you can eat them.

There are many asparagus varieties that are specifically suitable for a certain cultivation method, either white or green. These varieties simply don't taste as good if you start growing them the other way. For example, the tips of white varieties can open up very quickly if you were to try growing them as a green variant, or they are tougher if you choose the other cultivation method. And that is where dual-purpose varieties come into play.

Besides varieties that can only be grown white or green, there are also a number of varieties suitable for both cultivation methods. They produce good quality and quantity of both green and white asparagus. If you just let them grow, the asparagus will be green. However, if you create a mound—and it doesn't necessarily need to be covered in foil—they will remain white.

We also have a number of these dual-purpose varieties in our garden. Before you can harvest asparagus, you have already invested 4 years of your time and land into the plants. They first need to take root well, and you may only harvest minimally for the first 4 years. You can read more about that here. If I ever want to harvest white asparagus, I don't want to have to plant new plants and wait another 4 years. Fortunately, with a dual-purpose variety, that's not necessary, and I can easily raise one of our rows with a mound to harvest white asparagus from my own garden after all. If I want green ones the year after, I simply remove the mound and harvest green asparagus again the following year. It's that simple. With a dual-purpose variety, you are in control of the color of your asparagus.