These tomatoes have been living outside 24 hours a day for the last two weeks. I would never have thought about trying this before, but I work in a garden centre and the tomato seedlings remain outside all the time there and as it is just up the road from my garden and the tomatoes are stored outside on the north side of the garden centre I thought I would try it at home too.
As I see it, the benefits are that they toughen up earlier in the season, get more light and as we are enjoying unseasonally warm weather and more importantly night time temperatures I thought why not take advantage. So far so good. They seem to be doing well, not growing leggy in the slightest as they don't need to fight for the light. Six of the seedlings are from saved seeds of tomatoes already grown in my garden last year (a cherry tomato and a Roma tomato) and two seedlings are from Garden Organic's Heritage Seed Library http://www.gardenorganic.org.uk/hsl/index.php
I will be giving them a holiday on a windowsill evening times next week though as night time temperatures look to fall to 4 centigrade and I'm not that brave to see if they can cope just yet and risk losing all my seedlings in one swoop... well I might just test with one extra hardy one to see if they can cope at this tender young age.