Liming Acidic Soils 

By adding lime, you can increase the pH of acidic soil to make it better suited to vegetable growing. Crushed chalk or ground limestone are the safest and cheapest forms of lime to use. Apply them at the recommended rate for your type of soil; clay soils require heavier applications than sandy soils to achieve the same effect.

Treat the soil in fall or winter, at least four weeks after adding any bulky organic matter. Divide the plot into 1-square-yard sections with string lines. Wearing gloves, long sleeves, safety glasses and a mask, weigh out the correct amount of powder to treat 1 square yard. Sprinkle this evenly onto the soil with a spade, repeat until the whole plot is covered, then rake the lime into the soil.