Soil pH for New Guinea Impatiens Under Pine Trees: Testing and Amendment

Target pH

Impatiens prefer a neutral pH of 7.0. Pine needles acidify soil, so testing is essential. Inexpensive pH kits are available at garden centers.

Adjusting pH

• Too acidic: add powdered lime.
• Too alkaline: add ground sulfur.
• General rule: soils east of the Mississippi tend to be acidic; west tend to be alkaline.

Long-Term Fix

Amend with organic matter (compost, peat, aged manure, shredded leaves). High-organic soils rarely need pH adjustment because they buffer pH naturally while providing nutrients and disease resistance.