I don't know....I sowed mine in early March in heated propagator and they're now at the 4 leaf stage and only about 2inches tall, so quite slow really. I got my seed from Meanie and he sows his Jan and Feb in a heated conservatory.

I would give it a go Muddy..once they get going they grow quite quickly, you may get some flower this year if you are lucky!

I did indeed sow mine in February. I have one 6 inches tall, but they are still germinating too.
What Datura do you have? The single flowered white ones grow a hell of a lot quicker than the new cultivars, especially the doubles. If you can grow it undercover until June, I'd say that you have every chance of getting a white one into bloom. Soak the seeds for at least 24hrs, & I pot mine on a couple of times before planting into the largest pot you have mid June. Be warned, they are not the fastest thing (or the most reliable) to germinate.

I have Datura Ballerina Tutu which is a double and comes in all sorts of colours by the look of the packet. Thanks for all the tips - I am going to give them a go and see what happens. If they don't flower this year - do you think I would be ok to bring them in the house over winter and then plant out next year or would that be too warm for them?

I've overwintered my Blackcurrant Swirl (a double) in the conservatory & it has just given me it's first (admittedly not very good ) flower of the year.

Is your conservatory heated? I wanted to put these in a cool dining room if they didn't flower this year, but if they could make it in an unheated greenhouse - that would be even better.

Only heated when very cold or at weekends maybe. As long as they're kept frost free they'll be ok.

Thanks everyone for you help. Seeds are now sown - so I shall wait and see...fingers crossed!