So here I am in Zone 5, with a nice raised bed (about 2ft tall) along one side of my garden where it borders my neighbours. A perfect spot, thought I, for asparagus. Since they’re hardy to Zone 2/3, they’ll surely survive winters here in a raised bed with a pretty protected location.
I hurriedly transplanted some Jersey Knight over last November after they had gone dormant (didn’t manage to do it in the spring as that bed needed some work), planting them about 1ft deep. This spring, all dead. I dug a few up and they’re mushy and sad.
How did I manage to kill these guys? The crowns were healthy, the bed seems to have good drainage. A bunch of bulbs survived the winter in the bed and came up. Is asparagus not hardy enough for a raised bed after all? Should I have planted the crowns in the center of the bed rather than closer to the sides?
I started two 3x6 raised beds of two year old millenium crowns last spring. This year they are growing like crazy. I swear overnight some have grown over a foot. I don’t protect mine at all other than some straw as mulch to prevent weeds.
My guess is too deep to make it to surface. if you want the crowns a foot deep , try planting at that depth but only covering with a couple of inches of soil. As the plants grow above soil level keep adding soil without completely covering the growing stalks. Eventually the dirt will be at desired level and roots at desired depth.
Isn’t the purpose of planting them that deep to shield them from the winter? Most of the places I looked at online said to plant them 6"-12" deep, and that’s where they ended up being.
Digging them up it seemed as though none of the crowns had even attempted to bud in the spring, they were all soft and mushy.
The recommendations are so you can cover the roots and crown. If both the roots and the crown are covered you are good. Gardener Scott made a video on them and he is zone 5 Colorado which is pretty darn temperate of a climate.