How to Add Lime With Fertilizer
Yearly applications of lime with fertilizer are essential for keeping your soil healthy and rich. Lime is a calcium or calcium and magnesium rock dust. Fertilizer is made of varying percentages of nitrogen, phosphorus, and potassium (NPK). Lime and fertilizer work together to improve your soil and make nutrients available to plants. You can add lime and fertilizer at the same time, but spacing the applications is much more effective.
Test the pH of your soil in late summer or early fall. Lime is needed to adjust soil pH and “sweeten” it, or make it more alkaline. According to Purdue University Cooperative Extension Service, even alkaline or pH-neutral soil gradually becomes more acidic over time from the addition of nitrogen fertilizers and from the plants themselves.
Add lime according to the recommendations of the pH test. Adding too little lime will reduce its effectiveness, while adding too much can make the soil too alkaline for plants and reduce their ability to take up nutrients.
Apply lime in the fall. Spread it evenly over the surface of the soil or lawn with a garden spreader. Adding lime in the fall gives the soil a chance to process it before spring planting begins. It also gives you time to make any further pH adjustments, if necessary.
Test your soil pH again in early spring if it was very acidic to begin with. Add more lime if the pH is still too low (below 6.0). Wait at least a month after liming to add fertilizer. Microbiotic life in the soil consumes the fertilizer and makes it available to the plants, but the soil needs to be at the right pH for the bacteria and fungus to do their jobs. The University of Kentucky Extension Service warns that if you fertilize when the soil is still too acidic, much of the nutrients will have leached out by the time the lime has amended the environment for optimum microbiotic activity.
Fertilize the soil in spring before planting begins with a balanced NPK fertilizer, or an NPK fertilizer with the recommended ratio for your plants. Spring is the best time to fertilize because soil temperatures are warm enough for the fertilizer to be effective. The University of Delaware Cooperative Extension Service recommends digging the fertilizer 2 or 3 inches into the soil.
Side dress plants with more fertilizer when growth is established, if desired. Side dressing adds fertilizer along the base of a plant. Plants like tomatoes, beans and corn respond well to extra fertilizer mid-season. It is not necessary to add more lime until plants have been pulled up or tilled under in the fall because this chemical remains active throughout the season.
- Soil pH test
- Garden spreader
- NPK fertilizer
- Purdue University Cooperative Extension Service: Soil Acidity and Liming of Indiana Soils
- University of Kentucky Cooperative Extension Service: When To Apply Lime and Fertilizer
- University of Delaware Cooperative Extension Service: Commonsense Use of Lime and Fertilizer in the Home Vegetable Garden (PDF)
- Hewitt's Garden Source: Why Lime in Fall?
- Flower & Garden magazine: Lime Is Fertilizer's Helping Hand