Listen to Cranky.
Most tomatoes like long hot summers. If you live in a cooler climate choose tomato varieties that are adapted to your area.
I would remind people that growing tomatoes in the northeast was very difficult last year due to the "late blight fungus"
Where I live the plum tomatoes especially and others suffer blossom end rot. Cold weather makes it worse. The bottom half of the tomato rots. Calcium in the soil helps. So I use some lime which also sweetens the soil. I use Jersey green sand and bone meal for phosphorus, important for fruiting plants and also roots, like onions and carrots. Chicken manure is also good, but I find the tomatoes taste better with green sand, don't know why and it might be my imagination.
Soil temperature is really important. There are tricks to getting heat pumped into soil. Inner tube full of water, bubble wrap on the ground, a product called wall of water, black plastic. If you are in a hurry the best thing you can do is try to get heat into the dirt. One year I had a terrace with a rock wall. The sun hit the rocks and got them hot and the heat got into the dirt from the wall. That worked very well. But as the season progresses the plants can get too hot if you use these things.
Plants that are started in a house next to a window do not do nearly as well as in a green house in a controlled environment. So unless you can provide the all day light and warmth you might want to buy your plants. They will be much healthier and stronger at the time they go into the ground, produce tomatoes much earlier and more of them. When you buy starts the bigger they are the more they cost. I buy a half dozen big ones for earlier harvest and many smaller cheap ones.
