4 Plants in one pot? I know there's a belief that they like their roots cramped, but that's not been my experience - mine grew and flowered much better in the open ground than they ever did contained in a pot, so I'm not sure the theory re cramped roots is accurate. Pot them individually in fresh compost, place out when the weather's right for them.

How old are the plants they may not be flowering size and age yet

Hello Alta, I grow mine in pots, one huge pot and very cramped, last year was not a good year, not sure why, but I think slugs and snails got in the pot (little beasts) and they chewed the new growth, this has not happened before so I will be on the look out because I usually have twenty or more beautiful flowers. I will also give them a good liquid feed.

Another thing to check is the light levels: Agapanthus indoors need very bright light to thrive, perhaps even direct sun in the morning.

I lost half of the ones in a pot last winter....just left outside. Repotted the rest and lots of blooms. Now I hardly dare look. I put them in a mini greenhouse I bought in November, but when closed, there is no ventilation ...so I could have lost them with mould attack.

I put mine in a mini greenhouse every winter,Dorjac,and they have been fine..although who knows,after this year.!
I do wrap fleece all around them,and I think there will be enough ventilation,coming in from the bottom.Hope they have survived for you...

I checked yesterday and I think the Agapanthus are OK . The roots are white and juicy and well anchored and there is a hint of green at the centre of the shoots. I will put bubble wrap round, a touch of water, and pop them back in my little greenhouse. I must remember to open the top for a while most days.

Glad to hear they seem ok,Dorjac,I think they are tougher than we think..I haven't even got my plastic cover on this year,as the wind ripped my old one to shreds last year.They are just wrapped in fleece,with a pane of perspex glass on top of the pot,weighted down,and they look ok.