^ A good soil moisture level is one that allows the surface of the soil to complete dry out and moisture barely evident one inch down. Ideally the soil should not be watered thoroughly enough that water runs out the bottom (washing away water soluble nutrients) but enough that you don't find the frequency of your watering schedule to become excessive.
Water them again when they look like they need it, a slight droop forming - except that they will also slightly droop during high temperatures without a need for water yet. Eventually you will get a better idea of how much water they are consuming per the plant species, their size, the amount of wind and temperature so you can water when it is more convenient to your schedule but water just enough to get the plant by until the next anticipated watering.
It also depends on pot size. An arguably undersized pot will require more frequent watering, won't allow for the first inch of soil to dry out much, and may end up causing some root rot. Always go larger with pot size if you can, although being in Toronto you probably won't need over 10 gallons for a first year plant.
IMO if you are going to be away for long enough that you fear the plants would die from insufficient watering, that's the time to ask a neighbor to water them for you, giving instructions about how much water they should need, and delivering the plants to the neighbor if only a few and they aren't very near by so it isn't much of a burden on them.
