Asparagus is available in different varieties, each with their own qualities. Some asparagus varieties are very suitable as dual-purpose varieties. But that term in combination with a photo like the one below occasionally raises some questions from people. For example, we have already been asked "does the plant occasionally produce green asparagus and occasionally white asparagus?" or "do they grow alternately white and green?". That is certainly not the case. You decide for yourself what colour the asparagus is! I will explain how that works in this blog.
Why are asparagus actually white?
Let me start by explaining why asparagus is actually white. That is because it grows underground. Anyone who has ever driven around Brabant or Limburg during the asparagus season has probably seen them: large fields with lots of narrow hills covered in black plastic, the asparagus fields. And those hills are there for a reason. They ensure that the asparagus remains so beautifully white. Because the asparagus never comes into contact with sunlight, they remain white. Under the influence of sunlight, plants produce chlorophyll. But as long as the asparagus grows in the hills of sand, they remain white. The foil ensures that the heads of the asparagus, as soon as they start to stick out above the ground, also remain white. This way, the asparagus pickers can see from the bumps in the foil where an asparagus is ready to be picked. Furthermore, the black colour of the foil ensures that the soil warms up a bit faster, so that asparagus can be picked earlier in the season.
White vs Green
You now know that growing white asparagus requires some effort. You have to build a hill around the asparagus to keep it underground and white. Green asparagus, on the other hand, is a lot easier. It just comes out of the ground, turns green, and if you find it long enough, you can snap it off and eat it.
There are many asparagus varieties that are specifically suited to a certain cultivation method, either white or green. These varieties simply do not taste as good if you grow them the other way. For example, the heads of white varieties can open very quickly if you want to grow them as a green variant, or they are tougher if you choose the other cultivation method. And that is where the dual-purpose varieties come in.
Dual purpose breeds
In addition to varieties that can only be grown white or green, there are also a number of varieties that are suitable for both cultivation methods. They provide both green and white asparagus of good quality and production. If you just let them grow, the asparagus will turn green. However, if you make a hill, and that does not necessarily require 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 in the plants. They first have to take root well, and you are only allowed to harvest minimally in the first 4 years. You can read more about this here . If I ever want to harvest white asparagus, I don't want to plant new plants again and wait 4 years. Fortunately, that is not necessary with a dual-purpose variety, and I can easily raise one of our rows with a hill so that I can still harvest white asparagus from my own garden. If I want green asparagus the following year, I simply remove the hill and harvest green asparagus again the following year. It's that simple. With a dual-purpose variety, you can therefore control the colour of your asparagus yourself.
