1. What is pH and pOH?

pH and pOH are measures of acidity and alkalinity in aqueous solutions. pH measures hydrogen ion concentration while pOH measures hydroxide ion concentration. They are inversely related through the equation: pH + pOH = 14 (at 25°C).

2. pH and pOH in Plant Growth

Most plants prefer a slightly acidic pH between 6.0 and 7.0. The pH affects nutrient availability in soil and hydroponic systems. pOH is less commonly measured but important for understanding complete water chemistry.

3. How the Calculator Works

The calculator uses the fundamental relationship:

Where:

• \( pH = -\log[H^+] \) — Measure of acidity
• \( pOH = -\log[OH^-] \) — Measure of alkalinity
• 14 — Constant for water at 25°C

4. Using the Calculator

Instructions: Enter either pH or pOH value (0-14) and the calculator will compute the other value. You can also enter both to verify they add up to 14.

5. Frequently Asked Questions (FAQ)

Q1: What pH is best for most plants?
A: Most plants thrive in slightly acidic conditions (pH 6.0-7.0), though some prefer more acidic (blueberries) or alkaline (asparagus) conditions.

Q2: How does pH affect plant nutrients?
A: pH affects nutrient solubility and availability. For example, iron becomes less available at high pH, while phosphorus becomes less available at very low pH.

Q3: When should I measure pH for my plants?
A: Regular pH testing is important for hydroponics. For soil, test every 1-2 months or when plants show nutrient deficiency symptoms.

Q4: How can I adjust pH for plants?
A: To raise pH (more alkaline): add lime or wood ash. To lower pH (more acidic): add sulfur, peat moss, or vinegar (for hydroponics).

Q5: Is pOH important for plant care?
A: While pH is the primary measurement, understanding pOH can help when working with alkaline solutions or when complete water chemistry analysis is needed.