Adrian wrote:

Right....
The instructions mentioned the need for maintaing a temperature of 25c
in order to break the dormancy - about the only place I can do that
(reliably) is in my propagator - which is designed for seed-trays - so
has limited headroom. Do you think that my juice carton will do the
trick, at least until the tuber starts sprouting ?? If not, I'll have
to work on a 'Plan B'....

Well, I would dispute that it needs 25C to start sprouting - 20C is
enough, but it will certainly make a rapid start at those
temperatures. You will need to be extremely careful when transferring
to a pot later - unlike many plants a broken root will not branch, it
will die back completely. If the clear plastic cover is restricting
headroom in your propagator, there's nothing to stop you fashioning a
bigger one using stiffish wire and heavy duty polythene.

... Larger tubers are probably better
started in home-made (non-plasticised) cardboard tubes about 10cms.in
diameter and 20 - 25cms. deep.

Hmm - I could certainly make one of these - but then there's the
question of where to put it for the necessary warmth (no sarky
suggestions anybody !)

A warm windowsill would be enough, just don't let it get too cold at
night especially if you've watered it that day.

Gloriosa tubers are very prone to rotting if the compost is kept too
wet, hence the advice to avoid 'overpotting'.

Not sure I understand the term (......still - bit slow on the uptake
this morning !)

Over-potting means putting them in a pot that is too large in relation
to the size of plant. A small plant with a limited root system cannot
take advantage of a huge volume of compost immediately. The compost
remains too wet for too long, becomes compressed and air-less and
starts to deteriorate, which in turn causes the roots to rot. Plant
roots are stimulated by changing conditions within a pot. As the
compost dries out, they grow in order to 'search' for more moisture.
Keep them growing and you can't go wrong.

OK - currently the tuber is in about 25% vermiculite and the rest is a
'bog-standard' peat compost. I do have a quantity of peat-free compost
- would you think that would be better ??
Don't have any hort. sand..... but I'm sure I can get some...

Well it's a matter of choice. I don't like vermiculite because it
does not improve drainage or aeration in the compost and holds on to
water for too long. Perlite is better - it provides drainage,
aeration and doesn't hold on to excessive amounts of water. I have to
admit that I have never found a truly satisfactory peat-free compost,
but that's a personal thing I can just about live with.

You weren't sure which end was which with your Gloriosa. Generally,
on a fully dormant tuber, the 'active' end will be rounded, fatter and
can be almost toe-like.

I also have a Chinese Lantern Lilly (Sandersonia aurantiaca) tuber -
which looks broadly the same as the Gloriosa - but on a much smaller
scale - and has two 'branches' joined together in a bulb-like thing.

Any special suggestions for 'which way up' on this one ??

This makes things easier... Sandersonia aurantiaca is quite closely
related to Gloriosa and a complete Gloriosa tuber will look vaguely
like a giant version of the Sandersonia, but without a swollen rhizome
in the middle. The uppermost "bulb-like thing" is a swollen rhizome
connecting the tubers, but the growth will arise from the tips of the
tubers. Sort of 'shoulders uppermost, arms down' with the new shoots
developing at the ends of the arms. A bit of a strange analogy, but
I'm sure you'll be able to see what I mean. If you plant upright with
the 'shoulders' just below the surface of the compost the Sandersonia
will be fine.

The same applies to Gloriosa, but because they are quite valuable
suppliers split the tubers and they get at least two for one. A very
well grown plant may produce several tubers and at one time you could
get a complete set for your money, which gave at least two strong
shoots. Not so now

I'll report back when the
sun-room is a mass of vines & flowers with small tropical birds
nesting.

And when you've grown your plant on for a few years with plenty of
tubers to spare, you could try planting one out in a sheltered, sunny
spot in very well drained soil. It can be grown outside in milder
regions (as can Sandersonia and another 'cousin' - Littonia modesta),
but that's another story.

HTH.