How do daffodils know when to start blooming spring?
They do not know its spring they are triggered into life by a cold spell,many plants can be fooled into growing out of season ,a spell in the fridge works wonders,but once they start to grow they need the type of weather that would be normal ie temperature and length of day light hours,I grow new potatoes for Christmas its a matter of keeping them cold enough to prevent sprouting ,but above freezing.Planted in september the UK temperature and day light hours are very close to April when potatoes are normally planted.Hope this is helpful I do on a bit when I get started.
