Adjusting Soil pH: When and How to Use Lime

Soil test shows "too acidic" old soil. Owner seeks household alternatives to lime.

First: Verify Need

• Most indoor plants prefer slightly acidic soil (pH 6.0–6.5).
• Are plants showing nutrient deficiency symptoms (yellowing new growth, stunting)?
• Don't fix what isn't broken.

If Alkalinity Needed

Horticultural lime is standard: safe, cheap, reliable. No good household substitute – baking soda ratios unknown, slow, unpredictable.

Timeline

pH changes take a month or more to affect plants.