I have grown tomatoes a few times and I'd never really had a problem with them splitting but this year, I saw plants that were labelled as 'split resistant' and I thought hey, that sounds like a good thing...and lo and behold, they're splitting... go figure...

What causes splitting? It has been a very dry year, do they need to be watered more often? any suggestions?

There are all sorts of reasons why tomatoes split - sometimes it is too little water, sometimes too much. They are quite fussy plants. For most gardening questions I go to the University of BC Botanical Gardens forums - it isn't specific to western Canada - in fact people from all over the world access it for info. Give it a try

http://www.ubcbotanicalgarden.org/forums/index.php

the most common cause is uneven water . I grow upwards of 100 plants every year ( 8-10 varieties) and seldom have problems unless I get lazy in my watering habits and let them dry out too much between watering. That said, some varieties seem to be much more prone to splitting than others. Sungold ( a really nice orangey cherry) will split quite a bit even though it gets the same treatment as the others. As long as you have soil that drains pretty well its unlikely you can overwater them so my advice is, if in doubt water. I agree with fossil, the ubc site is excellent.
Happy gardening!
annie

Originally posted by alligator I have grown tomatoes a few times and I'd never really had a problem with them splitting but this year, I saw plants that were labelled as 'split resistant' and I thought hey, that sounds like a good thing...and lo and behold, they're splitting... go figure... What causes splitting? It has been a very dry year, do they need to be watered more often? any suggestions?

Buy a moisture meter then you can check in you are watering. evenly.