Whether you're growing vegetables, flowers or herbs, your garden soil must be fertile, crumbly and moist. Dry soil makes it difficult for plants to spread their roots and absorb nutrients. Extremely dry conditions will also affect the soil's ability to absorb moisture during heavy rains and may deteriorate topsoil as the water runs off. The addition of organic materials over several seasons will slowly improve dry soil, making it suitable for any plant.
Take some soil into your hand and attempt to crumble it to determine the texture of the soil. Excessively gritty soil is composed of sand. Small sand granules drain too quickly and require the addition of moisture-holding organic material. Clay soil, which clumps in the hand and does not easily break apart, requires the addition of sand.
Test the soil's nutrient levels using a soil pH test. Tests are available from gardening centers, with instructions included. Soil that is 7.0 or above is considered alkaline, while 6.0 and below is considered acidic. Alkaline soil requires the addition of sulfur to balance the pH, while acidic soil requires lime to raise the pH. Apply lime or sulfur at 1 lb. per 1000 square feet.
Add peat moss to the soil to improve its water-holding capabilities. Apply 2 to 3 inches of peat moss per 6 to 8 inches depth using a rototiller. Run the rototiller both horizontally and vertically across the gardening area to work the peat in.