How to Alkalize Soil

Alkaline soil has a pH above 7. Hydrangea growers know the importance of soil pH. Acid soil turns pink hydrangea flowers blue while an alkaline soil turns blue hydrangeas pink. Azalea growers know their flowering shrubs won't thrive unless the soil is acidic. Acid-loving plants find it difficult to absorb iron in alkaline soil and quickly become chlorotic. Many other plants, however, thrive in alkaline soil. They include boxwood shrubs, clematis, carnations and mock orange. Although it is easy to change the soil from acidic to alkaline, the changes are temporary.

Things You'll Need

• Rototiller
• Powdered lime

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Instructions

1. • 1

     Wait until fall to alkalize the soil. This gives the lime time to break down and seep into the surrounding soil before spring planting.

   • 2

     Til the soil to a depth of 12 inches in the area to be alkalized. Remove rocks, roots and other debris.

   • 3

     Pour 5 pounds of powdered limestone per 100 square feet onto the soil to raise the soil's pH by one point.

   • 4

     Turn the limestone into the top 10 inches of soil. Water the soil to that same depth after applying the limestone.