Great rose bushes need great soil in which to grow. Like many plants, rose bushes prefer loam--an equal mixture of silt, sand, organic material and clay. Most of us do not have prefect soil, so preparing soil for rose bushes before we plant them is a must. While making perfect soil takes time and work, adding compost and other amendments will help you prepare soil for rose bushes you can be proud to grow in your garden.
Remove all rocks and weeds from your garden.
Test your soil type. Gather a half a cup of soil from your garden. Place it in a jar and fill the jar with water. Shake the jar well and allow the soil to settle for two to three days. Once the soil has settled, sand will be on the bottom, silt will be on the sand, clay will be on the silt and organic material will float to the surface.
If your soil is loam it will have an equal amount each of these. More clay means your soil is clay like while more sand means your soil is sandy. Roses grow best in loamy soil.
Prepare sandy and clay soil by adding compost or manure. Add 4 inches of compost or manure per square foot. Work it into the soil to a depth of 6 to 8 inches.
Test your soil's drainage. Dig a small hole, about 6 inches deep and 3 to 4 inches wide. Fill it with water and watch how fast it drains. Water will drain from well drained soil in about 15 minutes. Fast draining soil will empty more quickly while poor draining soils will empty more slowly.
Prepare poor draining soil by adding 2 to 3 inches of coarse sand per square foot. Work the coarse sand into the soil by 5 to 6 inches. Extra compost or manure may be added as well.
Prepare fast draining soil by adding extra compost or manure. Add another 2 to 3 inches or compost or manure and work it into the soil to 5 or 6 inches in depth.
Test your soil's pH. Roses grow best in slightly acidic soil, about 6.5 pH. If your soil is too acidic it needs lime. If it is too alkaline it needs sulfur.
Prepare acidic soil by adding lime. Add 20 pounds of lime for every 100 square feet. Work it into the soil to a depth of 2 to 3 feet. Prepare alkaline soil by adding sulfur. Add 30 pounds for every 100 square feet. Work it into the soil to a depth of 2 to 3 feet.