I’ve been asked several times about preparing a site for growing asparagus, especially when the site you’ve chosen has lots of weeds and grass. Since I don’t grow my own asparagus, I decided to ask fellow Master Gardener Jerry Vitalis to share his wisdom on growing this crop. The rest of the article is Jerry doing just that.
On March 29, Tom Dickhudt and I taught a class on raising asparagus and growing onions. More than 40 people attended the class, and among the many questions was how to prepare a site for growing asparagus and it all starts with site selection.
Select an area that is well drained and has at least eight hours of full sun. Don’t plant near trees or shrubs, as the roots may pull moisture from the asparagus plants. Since you may be growing asparagus in this site for many years, get a soil test as soon as the soil is warm and firm. Asparagus requires a lot of nutrients, so a soil test will give you a good base line.
Keeping weeds, especially quack grass, out of your patch is the hardest job you will have, and this was a concern for many of those attending the class. I give my asparagus plants a fair chance by doing some of the following. The only time I used an herbicide was when I first created the planting site. I used Round-Up concentrate, six ounces per gallon, when the quack grass was four to six inches high. If you don’t know what quack grass looks like, do a Google image search. It comes up very early so if you see a very green grass like plant, it’s probably quack. Round-Up does not work in temperatures under 70 degrees so keep that in mind and it may take several days for the herbicide to kill the roots so be patient. The next step is to till or work the area level, then plant.
I would not be truthful if I said that was the end of weeds, but at least you give the new asparagus plants a running start. Quack, crabgrass, thistle, etc. will be forever present but if you are diligent in digging out new weeds when you spot them, you should be able to keep them under control.
The question was asked whether you can grow asparagus in a raised bed garden. Master Gardener Mark Stuart, who teaches square foot gardening, addressed that question by saying that, yes you can, and since you are using sterilized soil, you won’t have the weed problems you do with in ground planting. Square foot gardening is becoming more and more popular, so I’m sure it will be one of the class choices in our Spring Series of classes in 2017.