University of Maryland Extension

Planting Annuals and Perennials

Soil Preparation 

Preparing the soil is important for flowers, especially perennials. Although some annuals can grow and flower in poorly prepared soil, few perennials survive more than one year if the soil is not properly prepared. Prepare the soil in your flower bed in the fall before you plant.

  1. Have the soil tested early and adjust the pH if needed. Materials to adjust pH need time to work.
  2. Check and adjust drainage. To test drainage, dig a hole about 10 inches deep and fill with water. The next day, fill the hole with water again and see how long it remains. It should not exceed eight hours. If drainage is poor, dig furrows along the sides of the bed and add soil from the furrows to the bed. This raises the level of the bed above the soil level, allowing excess water to seep from the bed into the furrows. Prevent soil erosion during rains by surrounding raised beds with wooden or masonry borders.
  3. Dig the bed. Add four to six inches of organic matter to improve soil structure. Dig to a depth of 12 or 18 inches and leave “rough.”
  4. In spring, add fertilizer if necessary. Spade again, and rake surface smooth.
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