If you only buy two pieces of equipment for your hydroponic garden, make them a pH meter and an EC meter. They matter more than your nutrient brand, your light brand, and your system type combined.
What is pH?
pH measures how acidic or alkaline your nutrient water is, on a scale from 0 (battery acid) to 14 (drain cleaner). Water itself is neutral at 7. Hydroponic plants want it slightly acidic — between 5.5 and 6.5.
Why pH matters more than anything
Outside the 5.5–6.5 window, plant roots literally can't absorb most nutrients, even when those nutrients are sitting right next to them. Yellow leaves on a plant in nutrient-rich water? It's almost always pH.
What is EC?
EC (electrical conductivity) measures how much dissolved stuff — mostly nutrient salts — is in your water. The more nutrients, the higher the EC.
- Seedlings: EC 0.6–1.0
- Leafy greens: EC 1.0–1.4
- Fruiting plants: EC 2.0–3.0
How to adjust pH
Use "pH Up" (potassium hydroxide) and "pH Down" (phosphoric acid) — a few drops change the whole reservoir. A $20 bottle pair lasts most home growers years.
Meters worth buying
- Apera PH20 ($45) — accurate, easy to calibrate, our daily driver.
- Bluelab Truncheon EC ($120) — gold standard, lasts forever.
- Cheap combo pen ($15) — fine to start, replace within a year.
Frequently asked questions
How often should I check pH?
Every 3–4 days in a recirculating system. Plants change pH as they feed.
Do paper pH strips work?
Barely. They're too imprecise for hydroponics — get a digital meter.
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