Vegies need the soil (or potting mix) to be consistently moist, but not wet. It's easy to check moisture levels in the soil by digging around in the top few centimetres with your finger. You'll be able to feel whether the soil is moist, or if it's dry and needs watering. Depending on the weather, you'll need to water your vegie patch several times a week. During hot weather and when growing a potted vegie patch, watering may be required every day.
Applying a layer of mulch, such as pea straw or sugar cane, over the soil or potting mix surface, can help retain moisture. The added benefit of using mulch is that it can reduce weeds growing. If the soil becomes hard to wet (water repellent), applying a soil wetting agent, like Yates Waterwise Soil Wetter, will help get water down into the root zone.