Can You Fertilize, Lime, and Apply Insecticide All at Once?

When you're new to lawn care, it's tempting to tackle everything at once—fertilizer, lime, and bug control. But applying all three simultaneously can do more harm than good, especially on sandy soil with a pH of 6.0.

Why Timing and Soil Health Matter

Sandy soils drain quickly and lack organic matter, which means nutrients leach away fast. A pH of 6.0 is actually within the acceptable range for most turfgrasses (6.0–7.0), so lime isn't urgently needed. Adding lime at the same time as nitrogen fertilizer can cause the nitrogen to volatilize—essentially evaporating before your grass can use it.

The Problem with "Weed and Feed" Products

Combination products that mix fertilizer with broadleaf herbicides often deliver a heavy, fast-release nitrogen dose. This creates a quick green-up but weakens the grass long-term by discouraging deep root growth and harming beneficial soil microbes. The herbicide component can also stress young grass.

Better Approach: Build the Soil First

• Get a proper soil test through your local extension service (University of Delaware offers testing). This tells you exactly what's missing.
• Add organic matter—compost, aged manure, or humus—to improve water retention and microbial life.
• Mow high and often to shade out weed seeds and strengthen grass.
• Fertilize lightly with slow-release organic sources like Milorganite, alfalfa meal, or blood meal.
• Hold off on lime unless a soil test shows pH below 6.0.
• Spot-treat weeds manually or with targeted organic methods rather than blanketing the lawn with herbicide.

When to Apply What

If you must fertilize in summer, use a low-nitrogen, slow-release product. Apply lime only based on test results, and never at the same time as nitrogen. For insects, identify the pest first—many "bugs" are beneficial. Encourage birds and beneficial insects instead of reaching for broad-spectrum insecticides.

Healthy soil grows healthy grass that naturally resists weeds and pests. The quick-fix approach usually creates dependency on more chemicals. Invest in your soil, and your lawn will reward you for years.