There was a slight frost last night here in Aylesford (Kent) it was gone by morning, so personally I would not put them out just yet. Or you can put them out during the day and put back in the greenhouse later.

Gail

Thank you,I will do that

I wont be planting mine out till late April at the earliest but I am in East Yorks. they will be hardened off over 3 weeks in April. so they will go outside in the morning and back in in the evening etc.

Thanks again

And be ready for all out war with slugs and snails when you do plant them out. Its quite a challenge to get young delphiniums established. I think they must smell like beer to slugs! They come from miles around to munch on young delphs!