<img src="//bat.bing.com/action/0?ti=5587743&amp;Ver=2" height="0" width="0" style="display:none; visibility: hidden;">

Happy Earth Day! 🌎 Use Code: PLANET 🌎 Get 10% OFF now ⏰ Sale Ends 4/22 - SEE OFFER DETAILS 


GroLine is made for testing in all growth media.

Knowing what tools you need is easier said than done. Your growth medium, what you're growing your plants in, can be a deciding factor for what testing equipment you use. With a number of factors influencing plant growth, how is one to choose? We make it easy with our direct growth media testers, probes, and meters.

1. Direct soil testing actually means direct medium testing.

When it comes to Hanna direct soil meters and probes, they're actually designed for any growth medium. Coco fiber, organic soil, rock wool, clay balls, recycled plastic balls, bog, hydroponic systems, and more can all be tested with Hanna pH and EC testers. They also can be used in a variety of growth media blends. No matter the type of growth medium the way you test pH and EC directly is pretty much the same. You can make a slurry, insert the probe directly, or, use pore water (water extracted from the growth medium). Here's a quick rundown of the different types of growth mediums typically used, especially if you aren't sure which you are using.

Coco fiber

Coco fiberCoco fiber, also known as coco coir, is a by-product of processing coconuts. It is a more sustainable option than peat moss or bog, and the fibers allow for better aeration and water retention of the growth medium. Coco coir can be used as a stand-alone growth media, but more often than not it is used in a blend.

Organic soil

Organic soilOrganic soil is what most people think of when they think of gardening. Rich and dark in color, this type of soil is derived from composted materials (plants, mulch, manure). The broken-down material is full of natural nutrients and minerals. The soil tends to already have a well-established biome (microorganisms etc) due to soil composition and the way that the soil is made.

Inorganic soil

Inorganic soilInorganic Soil, though the name may not sound like it, is still a viable growth medium. Unlike organic soil, inorganic soil contains less than 30% of organic components. Inorganic soils are typically human-made and are considered "sterile" (ie. nutrients must be added, and the soil has little to no contamination. Inorganic growth mediums include rock wool, recycled plastic balls,, clay balls, hydroponic solution, and more. Growers may choose to use inorganic soil instead of organic soil for a number of reasons including the ability to more easily adjust pH, moisture, nutrients, and drainage.

Bog soil

Bog soil
Bog soil or peat can be used as a soil amendment and is found naturally around the world and takes years to form. Like coco coir, peat is used to increase a growth medium's ability to retain water. Due to its structure, bog also increases the porosity of a growth medium, it can adjust the pH, and it works well to hold onto nutrients. While an excellent resource for agriculture, peat moss comes from delicate ecosystems and is not necessarily considered a renewable resource,


2. They are built to withstand the rigors of direct measurement.

GroLine is as custom as your growing setup. You may be thinking, a pH probe is a pH probe. However, GroLine electrodes have been tailor-made to withstand testing in all plant growth mediums. How? Let us explain.

The sensor shape is made to easily penetrate into growth media.


The conical tips on the HALO2 GroLine Wireless pH Tester for Soil, GroLine Soil pH Tester, GroLine Professional Portable Soil pH Meter, and the Soil Test™ Direct Soil Conductivity Tester all allow you to easily insert the probes into the growth media. Not only that, the conical sensors provide strength and integrity to the probe so they are less prone to breakage. The Portable GroLine Meter - HI9814 with the HI1285-7 probe is a little different (beyond the fact that it tests temperature, EC, and pH...all with one probe!). The probe has a spherical/rounded bulb tip which maximizes surface area, but it also has a sturdy plastic body that ends with a "cage" around the sensor. This cage helps to protect the sensor when inserting the probe directly into growth media.

Clogged and sluggish probes are a thing of the past.

There's really nothing worse than getting into a groove when testing and all of a sudden the probe you're using stops working as well as it should. When working with growth media, many times the culprit is a clogged reference junction. This can lead to off readings and slow measurements. The new HALO2 GroLine Wireless pH Tester for Soil - HI9810302 showcases a unique open junction that has a removable sleeve. Not only can you refresh the electrolyte to improve performance, but cleaning is a breeze. Simply remove the sleeve to do a quick cleaning and electrolyte change. 

You may have already taken a peek at the GroLine Professional Portable Soil pH Meter - HI98168 and the Portable GroLine Meter - HI9814 and wondered why they have different junctions than the testers. The HI98168 has a probe that is excellent at taking readings in low moisture growth media. The triple ceramic junction allows the electrode to have a higher electrolyte flow rate, and this translates to faster, more stable, and more accurate readings in low-moisture settings. The retractable cloth junction in the HI1285-7 (paired with the HI9814) can be renewed when readings appear sluggish and this allows for faster response time.



3. We meet you at your budget.

No matter if you are a home gardener, a greenhouse grower, a farmer, or a hydroponics extraordinaire, testing pH and EC should always be easy and affordable. Here's a rundown of our recommendations.

Soil Test™ Direct Soil Conductivity Tester - HI98331 is really an EC solution for everyone. It measures conductivity and temperature and is pocket-sized. The EC probe is easily inserted into any growth medium.

HALO2 GroLine Wireless pH Tester for Soil - HI9810302 is the newest addition to our GroLine line-up. It may look a lot like our original tester, but it is so much more! The GroLine HALO2 has open-source Bluetooth capabilities allowing you to integrate it into current data logging systems (as well as the Hanna Lab App), specialized growth media probe design, and gives you a high caliber of testing and tracking your pH/temperature readings. It's like having a lab in your pocket! 

GroLine Professional Portable Soil pH Meter - HI98168 provides superior usability in the field with its rugged design and laboratory-grade accuracy. The probe that goes with this meter is great if you will typically be testing in lower-moisture growth media.

GroLine Waterproof Portable pH/EC/TDS Meter - HI9814 is the king of our GroLine portable meters. Designed for use in hydroponic solutions, this handy meter tests four parameters with one probe (pH, EC, Temperature, and TDS (ppm)), the HI1285-7. Alternatively, the Direct Soil and Soilless Media pH electrode HI12943 can be used with the HI9814 to test pH and temperature. It is ideal for greenhouse growers, hydroponics, and aquaponics.

Interested in more GroLine products for
all of your growth media testing needs?


Got Questions?

For more information regarding how Hanna Instruments can help you with all of your testing needs, contact us, at sales@hannainst.com or 1-800-426-6287.