1. Chose to grow only known a large-fruited tomatoes:
- 'Beefsteak'-type variety
- 'Big Beef'
- 'Big Rainbow'
- 'Dinner Plate'
- 'Giant Belgium'
2. Build your soil with a lot of organic matter/fertilizers in a 2-foot radius (at least) around the plants' future sites so they'll have an ample, natural food supply throughout the growing season. Ensure soil pH of 6.0 to 6.5.
3. Start plants indoors at least 2 months before the time to plant them outdoors. Keep seed pots slightly warmer (70° to 80° F) than average indoor temperatures. When the height of the seedling is three times the diameter of the pot, transplant it into successively bigger pots.
4. A week before transplanting outdoors, harden them off, stop fertilizing and watering, and put plants outside each day to help them adjust to new growing conditions.
5. Give your plants room to grow; 3 to 4 feet apart is about right. Until outside temperatures are above 60° F, cover them or enclose them with cloches, Wall O' Waters, clear plastic, or floating row covers.
6. Feed diligently during the growing season with weekly applications of a liquid supplement such as:
- a complete soluble fertilizer
- manure tea
- fish emulsion
Provide enough water so plantroots never dry out.
7. Support your plants with cages, stakes, or trellises. The fruit's weight can tear the branch away from the main stem, so support branches and large individual fruit with ties made from old pieces of cloth (wire or string ties tend to cut the stems).
8. Prune all suckers and remove the smaller flower clusters so your plants put all their energy into just a few tomatoes from the largest flowers. The largest fruits tend to develop on the lowest branches. Hand-pollinate selected flowers with a small paintbrush or by shaking the plants gently.
Ten Steps to Giant Tomatoes - National Gardening Association http://goo.gl/PqAw7
Terrific Tomatoes - National Gardening Association http://goo.gl/zrHyR
High Yield Tomato Plants: 50-80 lbs per Plant - YouTube http://goo.gl/65JmE