Mould on young apple trees

[Tobster]

I'm growing some apple trees from seed.

They're about 3 months old and were doing really well, but recently started to develop what look like mould spores on the leaves and stem.

I washed them all down yesterday, but the mould is back already.

My other half thinks I may be over-watering them, I think otherwise. They were replanted into those pots a few weeks ago; they were brand new from the garden centre, but also need mould wiping off them every now & then; I don't know if that's significant or not.

I've attached photos. The plants are clearly ill from whatever this is.

Does anyone know what this is and if there's anything I can do about it?

[Ross]

This is just a wild-assed guess but it may be way too dry in there (humidity wise). Why not put it outside?

Ross.

[Tobster]

Thanks for your reply.

They are indoors, and it's been a hot summer here up t'north, so I wouldn't call your guess wild-arsed.

But; I've been a bit reluctant to put them outside because they seem a bit fragile. How much wind can they stand up to at this age? Or is it not even an issue?

[Pat Kiewicz]

It's natural for them to be growing outside. But it's also true that moving them out into the sun and wind after being indoors would be harsh. The answer is to move them out to an area that's shaded and protected from the wind (most of the time, to start) and over several days, give them longer and longer exposure to full sun and breezes. That is, harden them off.