Do you mean Brussels sprout seedlings? If so in your vegetable bed if not which 'sprout' are you referring to?

I planted my brussel sprout seedlings (hope this is what you mean, Joanna) out yesterday in the garden - they seem to be quite undemanding and seem able to tolerate a range of conditions. "Bosworth" did very well in ordinary, unmanured soil and quite hot, bright sunshine last year, but was kept pretty well watered. This year they are in a shadier part of the garden. I didn't feed, either, but the soil is quite productive and has had loads of compost dug into it over the years. Make sure you patrol them well and check the underside of developing leaves for caterpillar eggs at least every other day and rub them off or you could lose the lot in a very short time. Don't overcrowd them, and water with a can near the base of the stems rather than using a hosepipe (if you are allowed) and getting the leaves wet and splashed with soil.