Tomatoes, in a heated greenhouse (minimum 10 degrees C) can go in any time between now and end of March. I sowed mine a month ago.

Early potatoes can go in the ground late march, early april.....Easter would be a good time. Just cover any top growth with fleece or something if night frosts are expected.

Hi, I agree with Badfish, just bear in mind that the 10 c is an absolute minimum, which is not such a problem in a propagator, but you will need to keep the greenhouse at this when they come out of the propagator, and this minimum applies throughout the life of the plant, tomato's stop growing below this, and also if they go above 27c they stop growing, Derek.

I start mine off in late March as by the time they are big enough to have to come out of the propagator the unheated greenhouse rarely gets too cold.