Soil Types

Improvement, Planting & Mulching
Good soil preparation and proper planting are keys to healthy plants and efficient use of water in the garden. Deep cultivation and the addition of compost or other organic materials enhance the soil's ability to absorb and store rainfall or irrigation water fro plants to use later. Good planting practices allow plants to develop healthy, wide spreading roots which draw water from a large area. These practices contribute to a healthy garden which resists drought and thrives with minimal maintenance and watering.

The Soil Reservoir
Soil is a reservoir that stores moisture and nutrients needed by plants to grow well. Plant roots are the pipes that transfer water and nutrients from the soil to plant leaves.

How well roots do their job depends on soil quality. In soils that are loose and rich in organic material, roots spread freely and can pull water and nutrients from a large area. Water is able to enter loose soils easily, and is stored in organic matter until plants need it.

Poor and compacted soils inhibit roots from spreading to reach nutrients and water. Water runs off compacted soils rather than entering the soil. Plants grown in poor soils can be stunted, and are susceptible to damage from disease, insects and drought.

What Kind of Soil Do You Have?
The only way to find out how well your soil is providing for plant roots is to dig in and check. Dig a one foot deep hole and remove a slice of soil from the side. How does it look and feel? Not compacted layers.
Clay Soil Sandy Soil Loam Soil
Clay and silt soils are made of very small particles. They feel slick and sticky when wet. Clay and silt hold moisture well, but resist water infiltration, especially when they are dry. Often puddles form on clay or silt soils, and they easily become compacted.
Loam soil is a mix of sand, silt or clay, and organic matter. Loam soils are loose and look rich. When squeezed in your fist, moist loam will form a ball which crumbles when poked with a finger. Loam soils normally absorb water and store moisture well. Loam soils can be sandy or clay based, and will vary in moisture absorbtion and retention accordingly.
Sandy soils contain large particles which are visible to the unaided eye, and are usually light in color. Sand feels coarse when wet or dry, and will not form a ball when squeezed in your fist. Sandy soils stay loose and allow moisture to penetrate easily, but do not retain it for long term use.
Few gardens start with the "rich sandy loam" that gardening books recommend for planting. The soil improvement and planting practices outlined below can help plant roots do better in any soil.

How to Plant Right for Healthy, Waterwise Plants

Break Up Compact Soil
Soils that are compacted inhibit drainage and root growth. Compacted soil must be broken up using a shovel, pick or Rototiller. For maximum root spread cultivate new garden and turf areas one foot deep, not just where individual shrubs and trees are to be placed. Break through compacted layers so roots can penetrate into looser soil below.

Add Organic Material.
Organic materials, such as compost, improve every soil type. Organic materials bind sandy soil particles so they retain moisture and nutrients better. They also break apart clay and silt particles, so that water can infiltrate and roots can spread. Amend soil by mixing 4-6" of compost or other organic material into the top 6-12" of soil in new garden and turf areas. Annual beds should receive an additional 1-2" each year. Composted yard waste or barnyard manure are the best soil amendments, because the nutrients are ready for plants to use. Fresh manure, grass clippings or shredded fall leaves can be used, but they must be allowed to decompose completely before planting. In poorly drained areas use a mix of compost and topsoil to created raised planting areas.

Mulch to Retain Moisture.
Mulch is any material that is spread on the soil to slow moisture evaporation, keep the surface loose and porous, and keep down weeds. Organic materials such as wood chip, ground bark and compost are excellent mulches which allow air and water to enter the soil, and add nutrients as they decompose. Mulch shrubs and trees with up to 6" of wood chip or coarse bark to protect the soil for years. Finer textured materials such as compost and ground bark should be in 1-2" layers. Mulch annual plants with 1-2" layers of compost, manure, grass clippings or shredded leaves which can be tilled in at the end of the season. Lawns may be top dressed with 1/2" of fine compost following thatching or aeration.