The best source of water for your garden is rain, as long as rain keeps your soil moist underneath the mulch, no watering will be needed. An actively growing garden requires at least 1 inch of rain per week. If you are not getting that or your plants wilt during the warmer part of the day, you probably need to water. During the first 3 weeks after setting out your plants, check moisture weekly. If the surface is dry beneath the mulch, dig down 6 inches with a trowel. If the soil is still dry at that depth water your bed. Later in the season after roots have reached deep into the soil, you need to water only if signs of wilting appear.
Water well but not too often. Soak the garden up to 4 hours at a time letting water soak deep, and then let upper soil layers dry out before watering again. This promotes deep root growth and a more lasting beauty and better harvest from your plants, and helps retard weed growth.
Several watering methods are effective. Ground watering with soaker hoses or a carefully placed hose soaks deep and avoids wetting the foliage, but these devices are sometimes hard to set up or move. Impulse jet sprinklers lay down a lot of water fast and are easy to move around but can beat small or tender plants down. A fine spray sprinkler of the oscillating or whirling type is both gentle and easy to move, but slower to water.