Begonia plug plants

loveunrequited

I’m having a nightmare with begonia plug plants I purchased, I potted them into 7cm pots so not too big, they are in multi purpose compost mixed with perlite, the roots don’t seem to be growing though, zero movement root wise. I’m careful about watering, I know they don’t like soggy soil, I even sprinkle vermiculite at the top of the pots to soak up any excess moisture. I’ve always had hassle with begonias, I don’t know what it is, I thought I’d try again this year but I think it will be the last time, maybe it’s where I live in Scotland, they are in a heated greenhouse though so I don’t understand why they are so problematic. 

My question is, is there anything else I should have added to the multipurpose compost/perlite mix to stimulate root growth? the only other soil additives I have are vermiculite and coco coir and peat moss, do they not like multipurpose compost? 

Any advice would be appreciated! 

Perki

They can be fussy when young. I would personally pot them on into smaller trays / pots. Although 7cm pots aren't big and suitable for most plants they will stay wet / damp for longer than a smaller pot. I almost let them dry out before watering again, I use the 40 cell trays they are about 2.5cm square each cell, water from below as well to reduce the risk of grey mould ( botrytis )

BobTheGardener

I think they may also be a bit fussy about strong sunlight when small, so best in a shady part of the greenhouse.  I haven't grown them for a while but found they did better under the staging than on top.