growing tomato plants
What next with growing tomato plants? Should I move them outside? I have been growing tomato plants from small seedlings on my window sill. They are now quite healthy and approx 30-40 cm tall. I have moved them once from their original pots into more spacious ones, and water them on average twice a day. Should they now be hardened off to move outdoors, or can they live their whole lifespans on the window sill? At what stage will tomatoes start to appear? I am in the North of England, if that is of any significance regarding climate, etc. Thanks.
Depending on the type you have, they may eventually get too large for the windowsill and would actually benefit from being outdoors, especially for the purposes of pollination if you want to see some tomatoes (you would need to hand pollinate indoors). For more information on growing tomatoes indoors, this article will help: https://www.gardeningknowhow.com/edible/vegetables/tomato/growing-indoor-tomatoes.htm
To harden off your seedling plants, this article will help: https://www.gardeningknowhow.com/garden-how-to/seeds/how-to-harden-off-your-seedlings.htm