peterbone
Mame
Just thought you could use some advice from a fellow Brit. Everyone has mostly answered your questions, but I'll add to them anyway. Your initial post makes it sound like living in the UK is a reason for growing inside. The UK is one of the best climates for growing outside. We rarely get very low temperatures that could harm trees and don't need to give much protection over winter, but it still gets cold enough to provide winter dormancy for temperate species. If you have an outside space then that is the way to go.
I know that you've said that you don't mind waiting for your seeds to grow. Firstly, realise that you'll be waiting at least 10 years before you start doing any bonsai. Secondly, the wait is not the only reason we don't start from seeds or cuttings. Growing from seeds takes a lot of horticultural experience. To do it successfully requires starting from many seeds since many will die. Only a small minority of them will ever be suitable for bonsai. This requires a lot of outdoor space and hard work. Much better is to look at the many trees that are already grown in garden centres or in the wild.
The UK is a great place to collect trees from the wild as we have many species that are good for bonsai and the laws are less strict on collecting them that in the US for example. I personally collect most of my trees from the wild (Hornbeam, Field maple, English Elm, Cotoneaster, Oak, Beech, Hawthorn, Blackthorn, etc).
I'd recommend that you join the weetrees.co.uk forum. Bonsainut is great but weetrees has mostly UK members and so can give you more specific advice.
I know that you've said that you don't mind waiting for your seeds to grow. Firstly, realise that you'll be waiting at least 10 years before you start doing any bonsai. Secondly, the wait is not the only reason we don't start from seeds or cuttings. Growing from seeds takes a lot of horticultural experience. To do it successfully requires starting from many seeds since many will die. Only a small minority of them will ever be suitable for bonsai. This requires a lot of outdoor space and hard work. Much better is to look at the many trees that are already grown in garden centres or in the wild.
The UK is a great place to collect trees from the wild as we have many species that are good for bonsai and the laws are less strict on collecting them that in the US for example. I personally collect most of my trees from the wild (Hornbeam, Field maple, English Elm, Cotoneaster, Oak, Beech, Hawthorn, Blackthorn, etc).
I'd recommend that you join the weetrees.co.uk forum. Bonsainut is great but weetrees has mostly UK members and so can give you more specific advice.