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Direct pH measurement in soil & soiless media

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pH is the most famous parameter in agriculture, and it has a good reason to be! It’s one of the parameters that is critically important to plant health.

Soil pH is directly connected to nutrient availability, or to simplify: ability of the plant to absorb and use the available nutrients.

Each family and type of plants&crops have a unique preferred pH range in which they can thrive the best. It seems like a lot of work, but it’s basically really simple, in the end your crops will reward you with maximum yield!

It would be so simple if you could take the pH measurement only once and forget about it, but this is not the case.

pH value of the soil can vary over time & with several factors:

  • Water used for irrigation can affect the pH depending on its specific alkalinity/acidity
  • Fertilizer selection. Logically, fertilizers can decrease/increase pH significantly
  • Plants itself; in different growing stages, plants can also cause a reaction with soil and differences.

There are several reliable ways to approach the soil pH measurements.

Many agriculture producers rely on methods like dilution or slurry. These techniques can be accurate, but require a certain amount of time and expertise.

Direct method – the fastest and most reliable method

There are several options of meters on the market that measure soil pH directly and giving you an instant result. Technique is very simple, a probe is inserted directly into the soil or soilless media and results is shown on the screen instantly.

Direct soil pH testing gives you the benefit of not needing to take soil samples, because the pH is tested right in the ground.

How to Test Directly in Soil

  • Using an auger or ruler, first put a hole down into the soil. The hole needs to be the same depth each time you test to avoid pH discrepancies.
  • Add some distilled or deionized water to the hole; the soil should be damp but not saturated with water.
  • Insert your testing instrument into the hole, and allow for the reading to develop or stabilize.

Simple!

How accurate is this method?

Each of our meters has a specifically designed probe for the application and specifications showing the resolution and accuracy.

Optimum pH Levels for Plants

Vegetable Plants

Optimal pH

Garden/Flower Plants

Optimal pH

Orchard Plants

Optimal pH 

Artichoke

6.5-7.5

Acacia

6-8

Apple

5-6.5

Asparagus

6-8

Acanthus

6-7

Apricot

6-7

Barley

6-7

Amaranth

6-6.5

Apricot

6-7

Bean

6-7.5

Bougainvillea

5.5-7.5

Cherry

6-7.5

Brussels Sprout

6-7.5

Dahlia

6-7.5

Grapefruit

6-7.5

Corn (Maize)

6-7.5

Erica

4.5-6

Grapevine

6-7

Cucumber

5.5-7.5

Euphorbia

6-7

Lemon

6-7

Early carrot

5.5-7

Fuchsia

5.5-7.5

Nectarine

6-7.5

Early Potato

4.5-6

Gentian

5-7.5

Orange

5-7

Egg Plant

5.5-7

Gladiolus

6-7

Peach

6-7.5

Late carrot

5.5-7

Hellebore

6-7.5

Pear

6-7.5

Late Potato

4.5-6

Hyacinth

6.5-7.5

Plum

6-7.5

Lettuce

6-7

Iris

5-6.5

Pomegranate

5.5-6.5

Melon

5.5-6.5

Juniper

5-6.5

Walnut

6-8

Oat

6-7

Ligustrum

5-7.5

 

 

Onion

6-7

Magnolia

5-6

 

 

Pea

6-7.5

Narcissus

6-8.5

 

 

Pepper

6-7

Oleander

6-7.5

 

 

Pumpkin

5.5-7.5

Paulownia

6-8

 

 

Rice

5-6.5

Portulaca

5.5-7.5

 

 

Soybean

5.5-6.5

Primula

6-7.5

 

 

Spinach

6-7.5

Rhododendron 

4.5-6

 

 

Strawberry

5-7.5

Roses

5.5-7

 

 

String Beans

6-7.5

Sedum

6-7.5

 

 

Sugar beet

6-7

Sunflower

6-7

 

 

Sunflower

6-7.5

Tulip

6-7

 

 

Sweet Potato

5.5-6

Viola

5.5-6.5

 

 

Tomato

5.5-6.5

 

 

 

 

Watermelon

5.5-6.5

 

 

 

 

Wheat

6-7

 

 

 

 

The HI98168 is a rugged, waterproof, portable pH meter that allows for the direct measure of soil pH. This meter is supplied with a specialized pH electrode that has a rugged conical tip for insertion in soil.

Besides being supplied with a unique pH electrode made for soil analysis, the HI98168 has the Hanna’s unique CAL Check™ feature that alerts the user to potential problems during the calibration process. This is a very important since it is likely that the probe will be coated with soil. This coating can easily lead to errors in pH measurement. 

By comparing previous calibration data to the current calibration, the meter will inform the user, with display prompts, when the probe needs to be cleaned, replaced, or if the pH buffer might be contaminated.  After calibration, the overall probe condition is displayed on screen as a percentage. The probe condition is affected by both the offset and slope characteristics of the pH electrode, both of which can be found in the GLP data including with the readings stored in the meter or transferred to a PC. 

  • Quick Connect DIN Connector
  • USB Connection for Data Transfer
  • Dedicated Help Button
  • ±0.002 pH Accuracy
  • Comes with all the necessary solutions and batteries- everything you need to get started measuring right away.
  • Specialized electrode for spot checking the pH of soil and soil slurries.

The HI99121 is the perfect portable  Direct Soil Measurement pH Meter. With the HI99121 and HI1292D direct soil pre-amplified pH and temperature probe, users can test both the pH of soil directly or after preparation of a soil slurry with deionized water. The HI1292D features a conical, rugged tip that can be directly inserted into moist or soft soil. For harder soils, the kit includes a plastic auger to perforate the ground.

The World’s First pH Electrode with Bluetooth Smart Technology for the Direct Soil Measurement HI12922

Our HALO® Wireless Soil pH Meter has a triple ceramic junction in the outer reference cell, built-in temperature sensor, and the conic pH sensing tip making it ideal for pH measurements in soil samples. All readings are transmitted directly to your Apple or Android device or the edge®blu.

Don’t worry, If this seems a bit too high-end for you, we have variety of testers also for the Hobby gardeners!

The HI981030 GroLine soil pH tester is an application specific designed pH tester for the measurement of soil pH. This meter offers many advanced features including the ability to clear any clogging of the reference junction, which results in a longer life than standard pH testers.

  • ±0.05 pH accuracy
  • Comes with all the necessary solutions and batteries- everything you need to get started measuring right away.
  • Specialized electrode for spot checking the pH of soil and soil slurries.

     

What do you need for obtaining most accurate results:

Clean Regularly | Calibrate Often | Condition Always

Author: Nives Vinceković Budor mag.ing.chem.ing.

 

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