Soil pH Management: Baking Soda, Coffee Grounds, and Epsom Salts

Baking Soda for Alkalinity: Proceed with Caution

Baking soda (sodium bicarbonate) raises pH but adds sodium, which can degrade soil structure and harm plants in excess. It's not a recommended soil amendment. Better for alkaline adjustment: garden lime (calcium carbonate) or dolomitic lime (adds magnesium too). Apply based on soil test.

Coffee Grounds for Acidity and Nutrition

Used coffee grounds are excellent for acid-loving plants (roses, blueberries, azaleas):

• pH effect: Mildly acidic (pH ~6.2-6.8 after brewing); gradual acidification.
• Nutrients: ~2% nitrogen, 0.3% phosphorus, 0.3% potassium, plus trace minerals.
• Application: Thin layers (½") mixed into topsoil or composted first. Avoid thick, wet mats—they mold and repel water.
• Enhanced mix: Combine with crushed eggshells (calcium) for balanced amendment.

For your Oklahoma rose: current practice (mixing grounds into topsoil) is fine. Monitor for mold; reduce quantity if soil stays too wet.

Epsom Salts (Magnesium Sulfate) for Roses

Rose growers swear by Epsom salts for greener foliage, more canes, and blooms:

• Application: ½ cup per mature bush, scratched into soil at drip line in spring (as buds swell). Or dissolve ½ cup in water and drench.
• Mechanism: Supplies magnesium (chlorophyll production) and sulfur (mild acidification).

Best Practice: Test, Don't Guess

Invest in a soil test (lab or quality kit) every 3-5 years. It reveals pH, nutrient levels, and cation exchange capacity—enabling precise, cost-effective amendments. Your rose's beauty deserves that precision.