Yes, normal compost with half the bulb protruding, as you say. I do the same.

Thank you Hywel.......last year my amaryllis (already planted) produced 18 flower heads......it was truly spectacular.

18 ! That's a lot ... I hope this year's will do the same :o)
The most I've had is 6 ...

The amaryllis was a red one bought from Scotsdales in Cambridge. It produced three stems and on each stem was 6 flower heads. It was a real beauty.

Hi, if you have a true Amaryllis, then you need to bury the bulb completely, just below the surface, in late summer, or in spring, as there is only 1 species of this, and is autumn flowering, what I suspect you have is a species of Hippeastrum, of which there are about 40, with many hybrids and cultivars, these are oten incorrectly sold as Amaryliss, but are less hardy, being frost tender, whereas Amaryllis is frost hardy.
You should plant the bulbs of Hippeastrum with the neck and shoulder above the soil in autumn, preferably in a loam based compost, {john innes no 2}, Derek.

You are quite right, Derek, what I have are two lovely large hippeastrum. I shall do as you say and hope for spectacular results later in the year. Thank you...Philip.