Cobalt Hollow
Cobalt Hollow
RootGauge

RootGauge™soil ph tester

$89.99

  • Moves With Your Soil, Not Stuck At 7
  • Calibrates so readings stay accurate
  • Replace The Tip, Not The Whole Meter
  • Four Soil Readings From One Single Probe

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  • Mix the included buffer powder with distilled water (one packet does pH 4 + pH 7 calibration)
  • Dip the spear tip, hold the calibration button — done in 90 seconds
  • Push the probe 2-3 inches into moist soil at the root zone
  • Read pH (to 0.1), moisture (1-10), light (lux), and soil temp on the backlit screen in 5 seconds
  • Rinse the tip with distilled water, cap, and store
  • Recalibrate monthly during heavy use, every 60 days off-season
  • RootGauge digital soil pen with backlit display
  • Replaceable hardened spear-tip probe (installed)
  • 2x AAA batteries (pre-installed)

We offer free shipping on orders over $150. Once your order is dispatched, the estimated delivery time is 5 to 12 business days depending on your location — tracking is emailed as soon as it ships.

Changed your mind? You can return your product within 90 days of delivery for a refund — see our Returns page for the full policy.

Why Gardeners Ditch The $15 Probe For This One

0.1 pH Reading Resolution

Reads in tenths, not whole numbers like the meters that always show 7. That resolution is what your state extension lab reports.

2-Point Buffer Calibration

Buffer powder included for pH 4.01 and 7.00. Calibrate each season and the meter agrees with the lab within 0.2 points.

RootGauge

Replaceable Spear-Tip Probe

Hardened tip shrugs off clay and rock where thin probes bend on the first push. Swap the $9 tip instead of buying a new meter.

Four-In-One Sensor Pen

pH, soil moisture, ambient light, and soil temperature on one backlit display. One walk-around handles raised beds, lawn, and houseplants.

Frequently Asked Questions

After 2-point calibration with the included buffer kit, RootGauge reads within 0.2 pH units of mail-in lab results — the same accuracy benchmark editors reported for $100+ pen meters. Tight enough to drive lime and sulfur decisions.

Cheap analog meters use a galvanic needle that pins at 7.0 in dry soil and rarely moves regardless of actual pH. RootGauge uses a calibrated digital sensor that updates every 5 seconds and reads to 0.1 — confirmed against pH 4.0 and 7.0 buffers.

Calibrate once at the start of the growing season with the included pH 4.01 and 7.00 buffer powders. During heavy use (5+ beds weekly), recalibrate monthly. Off-season, every 60 days is enough — the process takes about 90 seconds.

The spear tip is hardened steel, not the plated tin on $13 analog probes that bend on first insertion. If soil is very dry or hard clay, moisten it first and push straight down, never twist.

On 2 AAA batteries with auto-sleep enabled, expect 4-6 months of regular use (10-20 readings per week). The screen dims after 30 seconds and shuts off after 2 minutes. No Wi-Fi, no app sync — power use is only during an active reading.

Yes — the 0.1 resolution and built-in moisture sensor are useful for fiddle-leaf figs, monsteras, and seedling trays where overwatering is the #1 killer. Push the probe 1-2 inches in for small pots, 3-4 inches for larger containers.

Particularly useful here. Blueberries want pH 4.5-5.5; hydrangeas turn blue at 5.5 and pink at 6.5. The 0.1 resolution lets you actually hit those windows when applying sulfur. The built-in plant database lists target pH for 200+ varieties.

Those pens run $55-200 plus yearly calibration solution refills. RootGauge uses the same 2-point buffer calibration and lands within 0.2 pH of lab results, built for home garden beds instead of a commercial lab budget.

RootGauge is a digital soil pH meter in pen form. One probe reads pH to 0.1, soil moisture on a 1-10 scale, ambient light in lux, and soil temperature on a backlit display.

The package contains the digital soil pen with backlit display, a replaceable hardened spear-tip probe already installed, and two pre-installed AAA batteries. Calibration uses buffer powder for pH 4.01 and 7.00.
RootGauge

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RootGauge: A Four-in-One Soil pH Tester for Garden Beds

RootGauge is a soil pH tester in pen form for raised beds, lawns, and houseplants. A single probe reads pH, soil moisture, ambient light, and soil temperature on a backlit display.

As a digital soil pH meter, it reads pH in 0.1 steps and moisture on a 1-10 scale. A 2-point buffer calibration uses buffer powder for pH 4.01 and 7.00. The hardened spear tip is a replaceable probe, so the tip can be swapped without changing the whole pen.

  • pH, moisture, light, and soil temperature in one pen
  • Backlit screen for reading in the garden
  • Hardened spear tip installed
  • 2 AAA batteries pre-installed

Gardeners use this soil tester around acid-loving plants such as blueberries and hydrangeas, and for checking seedling trays. The pen works as a soil pH tester for lawn areas too.

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