1) SELECT VARIETIES THAT DO WELL IN YOUR ENVIRONMENT
There are so many varieties
to choose from that you will surely have success if you pick the right tomato to begin with. If your nights are cool, choose a cold hardy variety such as Stupice or Oregon Spring. If you have limited sun exposure, choose a cherry tomato that can develop with a little less light, or a determinate (see below) that can be planted in a large pot on wheels and may be moved into the sun.
2) DO NOT OVER FEED OR OVER WATER YOUR PLANTS
Too much nitrogen makes lots of pretty foliage but few tomatoes; too much water invites disease and makes mushy fruit. Cut back water sharply once plants begin to bear fruit. I'm sorry I can't be more specific about the amount of water but that has everything to do with the type of soil you have, how much fog, wind, temperature and general health of the plant. My best advice is this: If you think it needs water today, wait til tomorrow to water it. Try to water the soil, not the foliage, and early morning watering is best.
3) PRUNE TO CONTROL SHAPE
I admit, I do not do tis. Many people who grow on trellises prune judiciously. The argument for pruning is that you encourage he main stem and discourage side shoots for better production. We just let ours roam on the ground and get more tomatoes than we know what to do with.
4) STAKE OR TRELLIS
This is mostly for your benefit making for easier harvest and keeping fruit off the ground. The plant doesn't care. Now here is where I could go into a lengthy discussion of the annual tomato challenge that my Uncle Chauncy laid down at my fathers' feet. Chauncy trellised, Dad did not. Chauncy grew beefsteaks, Dad grew Rutgers all purpose tomatoes. It didn't matter in the long run. They both had bragging rights every year.
5) UPSIDE DOWN?
You might choose to grow tomatoes in the Topsy-Turvey upside down hanging planter bags. This works well for commercial growers but is a little difficult for home growers to manage, especially with regard to water and nutrient application. There are many good articles abut this on the internet, so do a little study before you try it. Personally, I think if you want to stress your plant to get more tomatoes, just remember to reduce water when they start to set fruit.
6) DETERMINATE OR INDETERMINATE
Determinate type tomatoes are usually hybrids developed for the commercial canning industry. All the tomatoes ripen at the same time as the plant dies back; putting all its energy into tomato production. These plants are smaller and more compact so do well in containers. (They are not good candidates for upside down growing, however, because they won't set a vine down from above.) Indeterminates are usually heirloom varieties and will produce smaller amounts of fruit over a much longer growing period. If you have the space, plant both types to get a big harvest early and a few big ones continuously through the season.
7) REALISTIC EXPECTATIONS
The first time I grew a Brandywine Pink tomato, I only harvested four tomatoes of a huge plant. I was very disappointed - but those four tomatoes were wonderful! I now know how fortunate I was to get any tomatoes of that large heirloom plant in my cool growing climate.
You CAN grow tomatoes! No mater where you live, there is a tomato plant that will work for you. (A friend of mine grows cherry tomatoes in her north-facing bay window in San Francisco.) Of all the vegetable plants we offer, nothing says summer like the tomato plant. We notice the tomato aroma from the tiny seedlings that come up in our seed room in January. And it is an aroma that is full of hope. I hope these few tips will help you harvest the best possible tomato - and that is the one you grew yourself!