Grow Gadgets Digital pH Meter Pen

The Grow Gadgets pH pen is a simple digital pH meter for plants: switch it on, dip it in the water or feed, and read the number. No colour charts and no squinting at test strips.

It is a lovely first meter for anyone starting out with hydroponics, rainwater butts or fussy houseplants that like their water just so.

A simple digital pH meter for plants and hydroponics

The pen covers the full pH scale from 0 to 14 and adjusts for water temperature automatically, so a cold tap reading and a warm reservoir reading are both fair.

When the electrode eventually wears out, it can be replaced rather than throwing the whole meter away, which is kinder to your purse and the planet. Pair it with our pH buffer solution and a bottle of gentle pH down, and you have everything you need.

When a pH pen comes in handy

• Checking water for a countertop herb garden or hydroponic bucket
• Testing rainwater and tap water for ericaceous plants like blueberries
• Adjusting feed for tomatoes, chillies and salad
• A hands-on science lesson about acids and alkalis

Why this pH pen is so easy

• Full 0 to 14 range. Reads anything from lemon juice to washing soda.
• Automatic temperature compensation. Fair readings in cool or warm water.
• One-button use. Switch on, dip, read; an off button saves the battery.
• Replaceable electrode. Swap the sensor rather than the whole pen.
• Battery powered. Small and light enough to keep in the potting shed drawer.

pH pen questions

What pH should water be for plants?
Most plants like slightly acidic water. Aim for pH 5.5 to 6.5 in hydroponics, and around 6.0 to 7.0 for compost-grown plants.

Can I test soil with a pH pen?
A pen like this is designed for liquids. Mix a little compost with distilled water, let it settle and test the water.

How do I calibrate it?
Use pH 4 and pH 7 buffer solution and adjust the pen until it reads correctly. Do it every few weeks.

How do I store the pen?
Rinse the tip in clean water, replace the cap and keep it out of direct sun.

The details

In the box

One digital pH pen with protective cap.

One dip, one number, happier plants. Simple as that.