Do you let your tomatoes go wild or do you train them?
In our first years, when we lacked any regular help on the farm, we experimented, sometimes out of necessity, with leaving our tomatoes unpruned and unstaked. We learned that while they will produce tomatoes, they won't produce nearly as many and will be much harder to take care of--and, almost certainly, the plants will become more diseased than their staked counterparts. (While old-timers may have grown tomato vines along the ground in much the same way as squash, contemporary disease pressures make this a bad idea.)
This year we are staying on top of tomato care. Staking keeps disease at bay and makes harvesting tomatoes (and hornworms) easier. Pruning helps plants to focus their energy into producing big fruit.
But what to cut and what to leave? And should you cage, string, or weave? Tips after the jump.
The goal of pruning is to create a main trunk and to eliminate too many branches. This encourages the tomato plant to focus its energy on developing fruit. Each time a shoot appears in the crotch between the stem and a primary leaf, we snip it off. If they are small it's easy to snap them off with your hands. If you missed one and it's grown larger, use a sharp pair of shears. Once our plants are 3-5 feet tall (depending on variety), we don't worry as much about branching out. We also trim off any bottom leaves that are touching the soil. These leaves can pick up disease through contact with the ground or back splash on rainy days. But don't over prune! Too much pruning all at once can stress out your plants. It's better to prune slowly and steadily as your plants grow.
Determinate tomato plants (like New Yorker) grow as a bush and don't need much pruning, but they do still need some minimal support. Indeterminate tomato plants (those that grow tall and viney) need sturdy, substantial support. Plants can be individually staked and tied to poles. We've even used old bed frames. They will also find support growing in wire cages. Because of the number of plants we grow (typically around 500 per year) we use the basket weave method. We sink 8 foot conduit 1-2 feet deep every 2 plants. Then we weave twine between the poles and plants. We add a new line of twine each time the plants get taller and start to flop over. This technique is known as the "Florida Weave"; this WikiHow article describes our process exactly (though it lacks pics--guess we'll have to take some ourselves). We use sturdy 6- or 8-foot T-posts at the ends of the row to keep the whole length from sagging and to prevent the pipes from bending (our rows are 75 feet long).
We avoid touching the plants early in the morning when they are still damp or after a rain. Most tomato diseases are transmitted through moisture. Dry days are the best times to do tomato care. Of course, some years you have few of these--so just do your best.
Additionally, we don't put tomato prunings in our compost pile. While at this time of year most tomatoes seem very healthy, we like to do our best to isolate potentially diseased foliage from healthy plants. So, bring a bucket along to collect the clippings, then dispose of the leaves and shoots in an area far from the garden, or, better yet, bag them and throw them in the trash.
As with everything else in your garden, you don't have to be perfect to reap a delicious harvest. Do what you have time for and let the plants do the rest! Even a wild, messy, tangled tomato plant will produce a tastier tomato than you can get at the grocery store!