What is white asparagus? You may have enjoyed this European delicacy in a fancy restaurant and found its mild nutty flavor more appealing than the herbal, bitter taste of green asparagus. If so, you probably want to grow white asparagus in your garden, but here’s a real head-scratcher. There are no varieties of white asparagus! So how does white asparagus grow?
What is white asparagus?
If you’ve seen plants growing on a wet paper towel, you’ve probably noticed that the stems are white and the leaves are pale yellow. These buds are not green because they have not started producing chlorophyll, the green pigment that gives herbaceous plants their color.
Some plants, such as asparagus, will not produce chlorophyll until they are exposed to sunlight. So what is white asparagus? It’s simple: the asparagus that never saw the light of day. White asparagus shoots can be produced by depriving any type of green asparagus of sunlight.
How to grow white asparagus
Before you can grow white asparagus in your garden, you must first establish healthy asparagus crowns that are at least three years old. Follow the recommended guidelines for soil preparation, transplanting, and fertilizing asparagus for the first two years.
White asparagus care can begin in the early spring of the third year. By this time, you should have a reasonable expectation of when asparagus will start to come out of the ground in your area. Before that date, put in place a way to prevent sunlight from showing asparagus sprouts:
Soil Mound – A mound of loose soil about 6 inches (15 cm.) in diameter is where the asparagus shoots are expected to grow. A frame of 6-inch (15 cm) boards can be placed around the asparagus bed to hold the soil in place. When you see the buds start to push the soil up, you’ll know it’s time to harvest. Carefully dig around each shoot and lift it below the surface of the soil.
Black Plastic Tunnel – This method is useful if you have unused row covers that can easily be covered with black plastic. There is no drilling this way and the asparagus sprouts stay cleaner, but the extra heat from the black plastic can be a problem. If that’s the case, try replacing the plastic with a black, porous fabric.
Plastic Pots – Dark colored pots can also be used to block the sun’s rays. They are easy to pick up for harvest, but will need protection on windy days. This may not be a cost-effective way to prepare large beds of white asparagus.
PVC Tubing – If you can locate where the asparagus plant is ready to germinate, a section of plastic tubing can be placed over the germinated asparagus plant. Push the tube into the soil, then cover the tube with a PVC sheet to block out sunlight. This method is quick and easy if you only want to grow a few spears of white asparagus in the garden.
Wooden Box – Make a wooden box with a lid and place it on the asparagus bed. Wooden crates are heavy in weight, but are ideal in areas where high winds are an issue.