Bluelab Soil pH Pen

Bluelab Soil pH Pen — Direct pH & Temperature Measurement in Soil and Growing Media

The Bluelab® Soil pH Pen is a portable, easy-to-use pH and temperature meter designed specifically for direct measurement in soils and growing media — no pH slurries or extraction mixes required. In soil-based and substrate growing systems, pH strongly influences the availability of nutrients and beneficial microorganisms to plant roots. Monitoring and adjusting soil pH directly from the root zone gives growers precise control over nutrient availability and plant health that reservoir pH measurements alone cannot provide.

The Soil pH Pen can also measure pH in liquid nutrient solutions, making it a versatile tool for growers who work across both soil and hydroponic systems. Easy-to-use buttons with selectable temperature units (°C/°F), a backlit LCD display for low-light grow room conditions, a successful pH calibration indicator, and hold and auto-off functions make the Soil pH Pen a practical, reliable everyday instrument. Low battery warning ensures you’re never caught off guard in the field.

Key Features

• Measures pH and temperature directly in soil, growing media, and nutrient solution
• No pH slurries or extraction mixes required for soil measurement
• Selectable temperature units: °C and °F
• Backlit LCD display for low-light environments
• Successful pH calibration indicator
• Hold and auto-off functions
• Low battery warning
• Portable and handheld — use anywhere in the facility or field

Frequently Asked Questions

What is the Bluelab Soil pH Pen and how is it different from a standard pH pen?

The Bluelab Soil pH Pen is specifically designed for direct pH measurement in soil and growing media, in addition to liquid nutrient solution. Standard pH pens are designed for liquid measurement only and cannot be inserted directly into soil or substrate without first preparing a pH slurry or extraction mix. The Soil pH Pen’s probe is designed for direct insertion into moist soil and growing media, delivering fast, accurate pH readings from the root zone without the extra preparation steps required by standard liquid pH pens.

Why is soil pH important for plant health and nutrient availability?

In soil and substrate growing systems, pH is one of the most critical factors determining which nutrients are available to plant roots. Most nutrients are most soluble and available to plants within a specific pH range — typically 5.5–7.0 depending on the crop. Outside this range, certain nutrients become locked up in the soil and unavailable to plants, even if they are present in adequate quantities. pH also influences the activity of beneficial soil microorganisms that support plant health. Monitoring and adjusting soil pH directly ensures that your nutrient program is actually delivering nutrients to your plants at the root level.

Can the Bluelab Soil pH Pen be used in hydroponic nutrient solution?

Yes. The Bluelab Soil pH Pen can measure pH in liquid nutrient solutions as well as in soil and growing media, making it a versatile tool for growers who work across both soil-based and hydroponic systems. This dual capability means you can use a single instrument to monitor pH across your entire operation, from reservoir to root zone.

How do I calibrate the Bluelab Soil pH Pen?

Calibration is performed using the easy-to-use push buttons on the pen with Bluelab® pH Calibration Solutions (pH 7.0 for buffer calibration and pH 4.0 for slope calibration). A successful calibration indicator is displayed on screen to confirm accurate calibration. Bluelab recommends calibrating the pen at least once a week in active growing environments. After use in soil or growing media, clean the probe thoroughly before storing it in KCl storage solution to maintain probe hydration and extend its service life.

Where can I buy the Bluelab Soil pH Pen?

The Bluelab Soil pH Pen is available through Seres Ag, a professional hydroponic and CEA equipment supplier serving growers across the United States. Purchase directly at seresag.com. Seres Ag offers expert product support, competitive wholesale and retail pricing, and US-wide shipping. For bulk or wholesale inquiries, contact the Seres Ag team through the website.