An adequate water supply near the garden plot is essential. Irrigation water can be applied by sprinkling or by the furrow method or by drip irrigation. It is important to apply sufficient water at proper intervals. The soil surface should be kept moist until plants appear.
Water-Wise Food Gardening has some good suggestions.
Estimating Irrigation Water Needs of Landscape Plantings in California - ETo Zones Map and WUCOLS IV (2014).