Acidic Soil for Planting Blueberries

Soil Test

• You may wish to do a soil test to determine the pH of the planting site, although most people skip this step and simply add acidic materials to the soil when planting blueberries. Soil-test kits are inexpensive and easy to use and are available at retail nurseries. Most university extension services will perform more accurate and thorough testing for a nominal fee.

Soil Amendments

• To make your soil more acidic, mix in natural materials such as compost or sphagnum peat moss. Adding potassium in the form of wood ashes, kelp meal or greensand also makes soil more acid.

Other Additives

• Aluminum sulfate often is recommended to acidify soil, but plants don't really need more aluminum. They need acid soil to take up the aluminum already present. Too much aluminum sulfate can burn plant roots and has been found in waterways. Sulfur is a safer acidifier. Sprinkle it on the soil at the base of the plant in spring and water it in.

Fertilizers

• Organic and synthetic fertilizers are available in formulations suited for acid-loving plants. Low in phosphorus and high in potassium, they are labeled for plants such as blueberries, rhododendrons, azaleas and camellias. Adding acid fertilizer at planting time and again each spring will help keep the soil pH favorable. When planting blueberries, mix in an acid planting compost whether planting in the ground or in a pot. Potting soil is usually alkaline.

Mulch

• Mulching blueberries with acid materials also helps keep the soil level suitable to their growth. You can use pine needles, shredded oak leaves, sawdust, sphagnum peat moss, compost or wood chips.