germinating information

[Catwheazle]

Is there actually a site where I can see whether the plant is light germinating or dark germination?
Particularly: Gentiana, Crocus, Primula

Thx
Bernd

[Ian Y]

Crocus germinate in the dark I Sow the seeds quite deep, Primula and Gentians need some light to germinate.

[SJW]

http://www.onrockgarden.com/germination-guide/plants

[Catwheazle]

Wow ... thx 

[Maggi Young]

Bernd - see this thread  for lots of seed germination information sources

[Tristan_He]

I generally take the approach that seed needs to be sown at a depth approximately proportionate to its size - so surface sown for small / tiny seeds (gentians, primulas, campanulas etc); covered for larger ones (most bulbs, peonies etc). This generally seems to work reasonably well for most groups, though there are bound to be exceptions.

Does anyone think top dressing colour might make any difference? For example a white top dressing like perlite lets in more light?

[Gabriela]

Yes Tristan, usually the rule: sowing depth - 21/2 the size of the seeds works well.

In regards with the seeds that need light for germination, actually the colour doesn't matter - as long as the material is transparent/translucent. It happens that expanded perlite is white and so is vermiculite (as well translucent).
I've heard about the use of quartz 'chips'; also quartz sand can be used (quartz is transparent and not necessarily white).

Using a coloured dressing may raise another question when growing under indoor lights - how it will influence the temperature at the pot level/ if this can be detrimental for some seedlings(?).