Asparagus seedlings

I have 30 4 inch high Asparagus seedlings growing in 3 inch pot's. I plan to plant them out next spring in a new bed. Do i need to pot them on before then and if so what size pot should i use?

If you've got a cheap and easy supply of compost/topsoil mixed, and space to keep them then they might as well go in 8 inch pots.... I did that with mine, from 15-cell module trays to big pots and they're thriving (two years later, having been planted out pretty much as you schedule it)... just getting m y first useable spears this year and it is uber-yummy....