If the soil is dry when planting them, then water them. If the soil is wet or damp, then I would leave them.

If you turn the earth over add some gritting sand to the area where you are planting the bulbs, that will help prevent water from accumulating there and causing them to rot.

Thank you but the bulbs are planted in pots so I will be unable to turn earth How often should I water them?

So you said! Pots wise, poke your finger in an inch or 2 and if dry water them.

If the pots are kept out in the open then don't bother about watering at all. They will get all that they need naturally. If the pots are undercover give them a good soaking now and then forget them; just make sure that they don't actually dry out. Start watering properly when shoots appear in spring.