Measurement of ORP in Hydroponics
Oxidation-reduction potential (ORP) is a critical parameter in hydroponic systems, influencing plant growth and nutrient availability1.
Understanding the optimal ORP range for hydroponic plants is essential for maintaining healthy growth conditions2.
Typically, ORP values between +300 mV to +400 mV3 are ideal for promoting oxygen availability and nutrient uptake in hydroponic environments.
Introduction
ORP measurement is integral to hydroponic agriculture, where plants grow in nutrient-rich water solutions instead of soil. It is essential for understanding the oxidative and reductive properties of the solution, which affect oxygen4 and nutrients availability. ORP levels influence the availability of oxygen and nutrients in hydroponic systems, directly impacting plant health and growth5.
Maintaining optimal ORP conditions is essential for maximizing nutrient uptake and promoting vigorous plant growth in hydroponic setups.
The optimal ORP range for hydroponic plants varies depending on factors* such as plant species, growth stage, and environmental conditions. Generally, ORP values between +300 mV to +400 mV6 are conducive to healthy plant growth in hydroponic systems. Deviations from this range can affect nutrient availability and oxygen levels, potentially compromising plant health and productivity.
LAQUAtwin ORP-11 pocket meter offers a convenient solution for monitoring ORP levels in hydroponic systems, providing accurate readings with a precision of ±2mV. With its compact design and user-friendly interface, the ORP meter facilitates efficient ORP measurement in hydroponic setups, enabling growers to optimize nutrient delivery and maintain optimal growth conditions for their crops.
Method
Collection & Preparation
- Collect water samples from the hydroponic solution reservoir, ensuring representative sampling from different areas of the system.
- Prepare the ORP meter for measurement, ensuring proper calibration.
Calibration
Calibrate the LAQUAtwin ORP-11 pocket meter using 225 mV standard solution to ensure accurate readings.
Measurement
- Submerge the ORP sensor into the hydroponic solution and allow the reading to stabilize.
- Record the stabilized ORP reading displayed on the meter, ensuring consistent measurement technique across samples.
- Rinse the sensor with clean water and blot it dry after each measurement to prevent cross-contamination.
- Measure pH using LAQUAtwin pH meter. pH affects the plants' ability to absorb nutrients.9 Generally, pH range of 5 – 6 is considered optimal for hydroponic.10
Table 17: Hydroponic health at different ORP levels
| ORP Nutrient Solution | < 250 mV | +250 - 300 mV | +300 - +400 mV | +400 - +450 mV | > 450mV |
|---|---|---|---|---|---|
| Hydroponic Growth | Risks: Nutrient solution lack oxygen. High nitrites level that is harmful to plants8 |
Nutrient absorption rate not at full potential. Possible infections |
Optimal condition* | Nutrient absorption rate not at full potential. Possible infections |
Root damaged if prolonged period |
Results and Benefits
ORP measurement helps hydroponic growers to fine-tune the nutrient solution, ensuring plants receive the optimal balance of nutrients and oxygen for healthy growth and maximum yields.
Regular ORP monitoring allows for early detection of potential problems such as nutrient deficiencies or oxygen depletion. Growers can take timely corrective actions to maintain ideal growing conditions.
By using the LAQUAtwin ORP-11 pocket meter, growers can maintain precise control over ORP levels, leading to consistent and robust plant growth in hydroponic system.
Table 2: Follow-up actions to increase ORP (Oxygen Level)
| Increasing ORP (Oxygen Level) |
|---|
1. Use of Oxidizing Agents
|
| 2. Air Pumps14 in Hydroponic Systems |
| 3. Bubbling Nutrient Solution With Air15 |
Table 3: Follow-up actions to decrease ORP (Oxygen Level)
| Decreasing ORP (Oxygen Level) |
|---|
1. Use of Reducing Agents
|
References and Suggested Readings
1,5,9,16 Jørgen Lissner, Irving A. Mendelssohn, Christopher J. Anastasiou. (2003, March 11). A method for cultivating plants under controlled redox intensities in hydroponics. Aquatic Botany. Retrieved from https://www.sciencedirect.com/science/article/abs/pii/S0304377003000172
2-3, 6,12,14 CCH2O. (2024, February 14). Hydroponic ORP Management. Current Culture H2O. Retrieved from https://cch2o.com/hydroponic-orp-management/
7 https://cch2o.com/hydroponic-orp-management/
4, 8 Oxidation reduction potential (ORP) - agrowtronics - iiot for growing. AGrowTronics. (n.d.). Retrieved from https://www.agrowtronics.com/oxidation-reduction-potential-orp/
10 Electrical conductivity and ph guide for Hydroponics - Oklahoma State University. Electrical Conductivity and pH Guide for Hydroponics | Oklahoma State University. (2017, April 1). Retrieved from https://extension.okstate.edu/fact-sheets/electrical-conductivity-and-ph-guide-for-hydroponics.html
11 Biksa, E. (2023, April 19). Hydroponic ORP controls. GROZINE. Retrieved from https://www.grozine.com/2015/05/05/hydroponic-orp-controls/
13 Biksa, E. (2024, January 16). ORP Meter Review. GROZINE. Retrieved from https://www.grozine.com/2024/01/15/orp-meter-review/
15 FloraFlex. (2023, May 10). Promoting healthy plant growth: A guide to hydroponic air pumps. Promoting Healthy Plant Growth: A Guide to Hydroponic Air Pumps. Retrieved from https://floraflex.com/UK/blog/post/promoting-healthy-plant-growth-a-guide-to-hydroponic-air-pumps#:~:text=Hydroponic%20air%20pumps%20are%20an,and%20promoting%20healthy%20root%20growth
LAQUAtwin: the only meters with flat sensor technology.
HORIBA’s highly-sensitive, flat sensor technology opens up new possibilities for sampling and sample types. Only a small amount of sample is required, so you can easily sample in situ without the need for beakers or other labware. Sensors are easily replaced as required.
Calibrate and measure at the touch of a button — the smiley face will tell you when the result can be read.
LAQUAtwin is fully waterproof and dustproof.
The meter and sensor are fully waterproof* and dustproof, so you can take it anywhere.
* IP67 rated. Will withstand immersion for 30 minutes at 1 m. Not suitable for underwater use.
Carry case comes as standard for handy portability.
The compact carry case contains everything you need for your measurements, including the standard solution and sampling sheets.
Matching products
