Tomatoes

Determinant tomatoes best grow with the support of tomato cages. Their plant DNA is sequenced to only grow upwards to a certain point, then bush out and start producing flowers/fruit. I do not recommend and personally do not prune any of my determinant tomato plants except for any branches/foliage that is within 6" of their base where the soil is. That goes for both types - tomatoes will suffer from disease from watering splash back and rot from low lying leaves.

Indeterminant tomatoes grow best with the support of stakes, pushed in about 6" from their base and supported to the stake with things like foam covered gardening wire or old panty hose. You will need to ensure that there is enough wiggle room for the plant to freely move in the breeze - do not cinch them right up the stake. Indeterminant tomatoes will keep growing upwards and onwards for the life cycle of the plant. I personally start topping mine once they reach 5-5.5 feet tall. Topping essentially stops the plant from growing vertically any further and starts the process of the plant bushing out and producing fruit. For indeterminant varieties, I feel personally it is best to be ruthless with your pruning routines. The more energy the plant can retain by not wasting energy in the suckers, more energy can go into sustaining growth to the fruit bearing branches resulting in better sized tomatoes and overall better yield. It is part of my weekly routine to go and prune back any leaves displaying signs of blight/disease, removing all suckers/clones and ensuring there is adequate air flow around the base of all my tomato plants.

Any of the suckers you prune off an indeterminant tomato plant can become whole new plants themselves! Bury the cut end in 4-6" of soil and watch it grow into a whole new plant. I have almost always successfully received fruit from my little tomato plant clones. The choice is yours - they compost well too!

All that being said, you can let your tomatoes buck wild and not prune a thing. You'll notice though that you'll have smaller and less tomatoes - which is ok depending on what your overall gardening goal is. Don't be afraid to screw it up on indeterminants. They literally grow like weeds with the right conditions.