Speckled Roman
Tomato (Plum) in the UK

You'll want to get your plum tomato seeds started indoors, usually around March or April up here in the North. Pop them in trays or small pots, about 5mm deep, in some good quality seed compost. They need warmth to get going, so a heated propagator or a warm windowsill with a heat mat is ideal, and grow lights will really help stop them getting leggy. Once they've germinated, make sure they get plenty of light, otherwise they'll stretch for it and be weak.

When your little seedlings have their first proper set of true leaves, it's time to prick them out into individual pots, say 9cm ones. Give them a good bit of space. Before planting out, you need to harden them off gradually over a week or two, you know, get them used to the outside world. Don't even think about putting them outside until all danger of frost has well and truly passed, usually mid to late May for us. In the greenhouse, give them about 60cm between plants, and they'll definitely need good support as they grow.