The type of soil you have ― sand, clay, or loam ― influences how fast water penetrates before running off, how often plants will need to be watered, and how much water you'll need to apply with each irrigation. Observe what happens to your soil when you wet it.
Sandy soils absorb water quickly without puddling. Compared with plants growing in clay soils, those in sandy soils need water more often, but since water penetrates sandy soils faster, you don't need to apply as much. In sandy soils, irrigate more frequently, but don't apply so much water that it will flow through the root zone without stopping.
Clay soils absorb water more slowly than sandy ones do; when water is applied too quickly, it puddles or runs off before being absorbed. Clay soils are slow to dry out; plants that grow in them are particularly at risk of diseases and other problems that result from overwatering. Stretch the time between waterings so plants have a chance to partially dry out. Apply water slowly so it doesn't run off before it can be absorbed.
Loam soils absorb water at an even pace without heavy puddling or runoff. You can recognize loam by picking up a moist handful; when you let go, it holds together but falls apart easily with some gentle prodding.
Most soils are a mixture of clay, sand, and loam. Identify what predominates in your soil and adjust your watering accordingly.
Soil texture and water penetration
Applied to sand, 1 inch of water penetrates about 12 inches.
Applied to loam, 1 inch of water reaches about 7 inches down.
Applied to clay, 1 inch of water soaks only 4 to 5 inches.