Seven year old asparagus plants growing in a 20 litre container filled with perlite.
The asparagus was raised from seed sown in a small container of perlite. It was grown in 20 litre bins of perlite for the first few years. When the crowns matured I transferred some of them to an old bathtub which was half filled with expanded clay balls. Although they grew very well in this medium I think that the asparagus grown entirely in perlite fared better on the whole.
Once the plants were three years old they were strong enough to harvest during the Spring. About 10 mature asparagus crowns produced more than enough fresh asparagus spears for us from September through to early December.