how do bulbs know?

[caladina]

might be a bit off topic?
i was wondering how bulbs know when to shoot up?
i have had some hyacinth bulbs down in my cellar for alooooong time.
no natural light gets to them at al, and they have just been left, discarded even, but they still shoot up
so, what do bulbs use to know when to do their stuff?
i, obviously don't know, its probably a very obvious answer that i should know but never had time to look or learn
do they use magnetics in the earths field? the suns gravitational pull?

[Hedge Witch]

A rice in temperature will break dormancy in hyacinth. Above 4 oC.

I don't think they need light to start growing.

[caladina]

if anything where the bulbs have been, its gotten colder

[Susie]

I seem to have a real problem growing hyacinths indoors. They start off okay but then start flowering before the flower spike is more than an inch tall and then it all goes horribly wrong.

[Meta menardi]

Originally Posted by Susie

I seem to have a real problem growing hyacinths indoors. They start off okay but then start flowering before the flower spike is more than an inch tall and then it all goes horribly wrong.

And then smell like an awful room freshener. I hate the smell, it makes me heave.

Plants have a load of ways of clocking when to grow and flower, and I am not sure which hyacinths have.

[Susie]

I love the smell.

[Hedge Witch]

I love the smell too Just bought 3 potted bulbs from Asda as a treat - looking forward to the blossom