watering.

If you search with google you can find all sorts of advice, but there are so many factors such as what sort of systems are you using (grow bags, pots, in beds) are they inside/outside? Type of soil also makes a differnce as some dry out much quicker. Also mulching or covering the soil with plastic can reduce the amount of evaporation from the soil.

Its all very subjective in the end, if they are in pots then I find its easy to judge if water is needed by feeling the weight of the pot, when they are dry its easy to pick up or just nudge a bit. For toms in the soil/compost/grow bags I stick my finger in a bit (not too near the roots) to feel how wet it is. Generally I water twice a day for my greenhouse toms.