Raised asparagus bed

I have a shallow raised bed of asparaus which is just 3 years old and I am about to replace the temprary wooden edging used to create it.  The new edging will allow me to increase the depth of the bed by about 3 inches giving the crowns a deep mulch of both manure and compost.  Should I mulch to this depth straight away or do it over a couple of years?  Aslo should I do it now just as it's about to starrt gowing or leave it to the end of the season?

Hi Gerrya, would be interested to know how you control weeds in your asparagus beds, I have just planted 3 different types on my 1st allotment. Many years ago I knew a chap who grew it for a living and he used to cover it with table salt to kill weeds.( It's a long story how I know this but it's all to do with Ostriches ) I don't mind weeding and that's probably how I'll cope with it.

Hi Ruby3,

I don't seem to have a great deal of trouble so far with weeds.  The bed is only just in it's 3rd year and is mostly new compost/manure which naturally acted as a mulch killing alot of the seeds etc of the original plot which was a lawn.  I only seem to get a bit of chickweed and the odd dandelion seedling and these are easy to pull if I get them when they're young.

My biggest concern is how deeply can I get away with burying the crowns now I've raised the sids of the bed.  Being inexperienced I didn't plant them very deep when I first put them in so could probably get away with an extra 4 inches but all at once or over a couple of years?  I've just put on about an inch of spent compst from soem potatoes grown in bags last year so I might just add a bag of manure now to feed it and then top it up again in autumn when I cut down the ferns.