Soil Testing

• Performing a soil test on the bed before adding amendments into the soil provides an accurate assessment of what is needed for your flower bed. Soil tests primarily indicate the pH level of the soil but they also determine the nutrient needs of the soil, which helps determine the best fertilizer choice. Perform a soil test at least four weeks before you plant because it's difficult to alter the pH of the bed once the flowers are sown. The soil pH indicates the acidity of the soil. Most flowers thrive in s pH near 6.5, but the exact number depends on the specific variety.
  
  

Lime and Sulfur

• Agricultural lime raises the pH of the soil by increasing the alkalinity in the bed so it isn't as acidic. Tilling the lime into the soil before you plant raises the pH to the 6.5 level. Beds with a high pH require a sulfur amendment. The sulfur increases acidity in the soil so the pH level lowers to one suitable for flower growth. The amount of lime or sulfur amending is dependent on the pH level indicated by the soil test. Beds that have successfully grown flowers in the past may require no amending prior to planting.
  
  

Organic Matter

• The organic matter in the soil determines the quality of the garden bed. Organic materials ensure proper drainage and water retention while also providing some nutrients. Soil with plenty of organic matter also has a crumbly texture that allows plant roots to penetrate easily. Till compost into the bed to improve the amount of organic matter present. Even good soils benefit from compost before planting. Tilling in a 3- to 4-inch layer of compost improves the quality of clay and sand soils so plants can grow in these otherwise poor locations.
  
  

Fertilizers

• All garden beds benefit from additional fertilization. The amount and type of fertilizer depends on the type of the flowers and the native nutrients available in the soil. Most flowers respond well to a general-purpose fertilizer applied at planting and again at midseason, such as a 5-10-5 or 12-12-12 fertilizer blend. Use the soil test as a guide for fertilizer amounts when available, otherwise till in the fertilizer at the rate recommended on the fertilizer bag for your garden size and flower types.