'Blind' overwintered strawberries

Can anyone help please and tell me why it is, that I have'nt got any strawberries on my overwintered runner plants from last year?   They were kept free from frost with fleece in a mini greenhouse over winter, watered when they needed it and mouldy foliage removed.  I planted them out in big pots as I don't have any garden to speak of, and all I am getting is a few strawberries, presumably from the main plants I bought last year-was hoping for a good crop