bigger the better realy as its more like a natural situation .

And it is likely that some will not survive in a container at all no matter how big it is. Wild flower seeds prefer to be in the ground. Lupin will need a deep container as will hollyhock as they will grow to a metre or more in height.

Most lupins are perennials and will not flower the first year. You need to sow the seed as it says on the packet then pot them up individually. the following year you can plant them out in their flowering positions. I bought some (rescued them) and planted them in pots last year. The kind of pots supermarkets use for cut flowers. They are growing away fine and I only lost two over the winter. My daughter had a small back yard and we used every container we could get our hands on to plant up. We had an old redundant cold water storage tank when the flat was replumbed. We had an old white sink which was lying in the yard when she bought the flat. The council decided to suppy wheely bins so a few of the redundant black plastic bins found their way in to the yard. We had a couple of large fish boxes which we painted and a couple of tubs which came from a bakery. The "Garden " was a great selling point when she moved. .

the ground is the most natural place and the very biggest pot you can get lol .