Asparagus roots should be set in deep 10 - 14 inch furrows or trenches at least a foot wide and deep. A high level of monoammonium phosphate fertilizer (11-52-0) should be worked into the trench area below where the roots are placed. You'll want to cover the roots initially with two to four inches of soil. As the plants grow the furrow should be filled-in with additional soil. You shouldn't "push the roots down," just backfill over them. Your seeded asparagus should produce after the first or second year.

Greg
Southern Nevada

Because crowns, as they develop, rise up not down. Exposed crowns die.

Dave

They also need that depth to stand up well. Think of a post: it will stand up with just a few inches buried, but it will not bear wind or weight unless it's buried at a proper depth. The same is true with asparagus. The ferns will blow over and break unless properly rooted. As Dave noted, crowns also die when exposed. I personally prefer my trenches a foot deep but narrow--no more than 4-6 inches wide. I don't want to backfill that much, and I can rest the crown against the wall, keeping it upright as I cover it. I used to make little mounds and babied them. What a waste of time. It's like your first child compared to your fifth. You learn they'll survive without your constant obsessing.

Brook

Brook

Digging those kind of deep trenches in early spring is prohibitive here in the Midwest unless you are digging in high sandy ground...been there...too wet.

Dig them now and they'll be ready to plant in the spring.

Greg
Southern Nevada

tc,

Important to know that unless you have an unusual site for our region -- that is, well drained -- it's best to have a rather deep raised bed, then follow the direction to plant at 6 inches.

Here, if you plant in the oft recommended trench, the asparagus will drown! Not a good thing.

I concur with Jean, I;m in So,Oregon and we get ample rain also... If you can go wit ha raised bed and then go with 6" deep,every wear your organic material will disappear and you will have the opportunity to add a couple more inches on top of your crowns...
If you care to look,I have a video describing how I did it..
There are 6 short video's, the link is to #5

Here is a link that might be useful: Square Foot Asparagus Plantings

Interesting bunch of replies. Thank you all.
Jean, my soil in Canby is a sandy loam. Extremely deep, very well draining. It is actually some very unique soil and a shame that there are houses being built on in around here. The farmers like it cuz it can rain one day and they can be plowing the next day.
I will be planting on a borderless bed raised up only 4-6 inches. I am more worried about Symphylans than drainage. I know there are symphs in my garden by not in extreme numbers yet. I try to manage them by letting beds go fallow for a year or at least dry out completely thru the summer. There won't be any symphs in the asparagus beds initially since they will be new beds where only weeds have been growing.
Jonhughes, I've seen your videos before as I was researching asparagus. I don't do the square foot thing since my soil is more than adequate. I will be adding compost and a bit of organic fertilizer (ala Steve Solomon) at the surface every year.
Forpitysake, what you said rings true with my experience in general. These are tough plants that will find their own way in time if you give them what they need.
After all of this, I think I may compromise and plant the crowns three inches deep and let them figure it out. I seriously doubt they will rise up out of the ground. I think they will seek their own level regardless. I still see no point to putting them 6 inches down.
I will dig a nice trench and put some compost and COG and bone meal underneath to get them off to a good start.

Except for a few plants that grow only in special conditions I've found that plants will pretty much do the right thing by themselves. I don't get overly obsessive about any plants, especially ones as rugged as asparagus. I just stick a shovel in the ground, plunk them at the bottom of the hole with the roots spread and cover tham back up without worrying about how deep that is. They'll find their way to the surface by themselves. If they fall over in winds or heavy rains just ring them with planting stakes and run some twine around the stakes.