For one or two containers, a liquid test kit is the better buy. A pen earns its place when you are testing several containers or want exact numbers.
Liquid Test Kits
You put a small sample of solution in a vial, add a few drops of indicator and compare the color with a chart.
- For: cheap, nothing to calibrate, nothing to break, reliable for years.
- Against: reads in steps of about half a pH unit, the color can be hard to judge in poor light, and dark or tinted nutrients can throw the color off.
pH Pens
A pen has a glass probe that you dip in the solution, with the reading shown on a screen.
- For: fast, precise to a tenth of a unit, easy to read.
- Against: costs more, needs calibrating with buffer solution, and the probe must be stored wet. A neglected pen gives confident wrong answers.
How Precise Do You Need to Be?
The target for strawberries is a range, 5.5 to 6.5, not a single number. A drop kit shows clearly whether you are inside that range, which is all a small setup needs.
If You Buy a Pen
- Calibrate it when new and then regularly, following the maker's instructions.
- Rinse the probe after each use.
- Store it with the cap filled with storage solution, never dry and never in plain water.
- Keep a drop kit as a cross-check. If the two disagree, recalibrate the pen.
The Short Answer
Start with drops. Move to a pen if testing becomes a chore or you add more containers.
Related guide: Measuring and adjusting pH.
