What planting medium for a bulb frame or bed?

[John85]

After reading what Ian told us about perched water tables in pots with a drainage layer at the bottom,I wonder what is the best way nowadays to make a bulb bed or frame?
I guess that the design adviced in the Bulb Book(Phillips and Rix 1981) is no longer recommanded as there are several different layers.
When the soil in the garden is heavy some drainage pipes are probably necessary at the bottom of the frame.
Traditionally gravel is used around them so that they don't clog but Ian has thrown such a big spanner in the cogs that I wonder what to do.

[PeterT]

In general course sand works very well. Some plants/ bulbs seem to need a clay/ loam content which also ensures that sudden very hot weather doesn't send the bulbs prematurely dormant. For less arid conditions add more organic material too. it all depends on the plants you are growing and your climate really.
If you are only plunging the pots then a raised bed of pure course sand is quite adequate. If the ground undeneath is very wet; a barrier of gravel or a membrane may help.

[Gerry Webster]

I don’t think you will have any problems with the basic Rix & Phillips design. You could omit the peat/leafmould  & instead wash coarse sand into  the 30cm bottom layer of rubble/gravel. I’ve used frame beds like this for over 20 years.

[Ian Y]

John

I think that in most cases the method described by Rix, (one of my heroes) and Phillips will work well enough but not for the reasons they initially thought.
The passage of water through substrates has been understood for a very long time it has just taken growers a while to catch up - especially many of the so called 'celebrity' experts who appear on our TV's.

The rule is simple the drainage should be good and all the way through the growing medium.
If you are making raise beds there has to be good drainage for the water to escape at the point where the growing mix sits on the natural ground. As you correctly suggest in some circumstances this may require the use of drainage pipes of some kind.