Hydroponic Water Testing Basics: Maintaining a Healthy Garden


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Known to be easy on space and environment, hydroponics is a fantastic growing method. It has been touted as a more of a “hipster” approach to vegetable farming versus the traditional soil-based garden culture. However, despite the cool factor, hydroponic farming tends to scare a few people away because of the difficulty associated with water maintenance. 

To some degree it’s true, there is a bit of a learning curve with setting up a hydro-garden. Many beginners minimize the need for consistent testing, and it ends up costing them big bucks eventually. It is not unheard of to have to replace an entire system because of damaged equipment. Imbalanced water gone unchecked for a long time can clog pumps, cause corrosion, and vegetation death.

Regardless of where you are in your hydroponics journey, the essentials of a successful system boil down to water quality, testing, and best practices. Many have asked why they should choose hydroponics over a traditional soil garden. There are tons of benefits, but like many hobbies – it’s fun and gives you an excuse to have your friends over for homegrown eats! But seriously, keep reading. Hydroponics helps our environment, global food supply, and a host of other great reasons outlined below. 

Hydroponic Water Maintenace Sounds Difficult, So Why Consider It Over a Traditional Soil Garden? 

For both newbies and expert growers, the benefits of establishing a hydroponics system are well worth exploring. 

  • Hydroponic systems reduce the need for a large amount of acreage. Even for the hobbyist, hydroponic systems have a notable smaller footprint. The design schemes can be creative and flexible which serve to accommodate a variety of growing situations. Many of the systems are indoor-friendly which can be kept year-round and helps to keep fragile vegetation away from harmful outdoor elements.
  • Hydroponic growers use minuscule amounts of pesticides and herbicides comparatively. Since most commercial hydroponic systems are set up in greenhouses, there isn’t the same need to fight plant-eating insects. If needed, they typically only use organic pesticides so they can still get their organic certification for their crops. 
  • Hydroponically grown produce uses on average 90% less water than soil-grown produce. This is a huge consideration for improving the use of our natural resources. The water requirements are far less than soil and can be augmented much more efficiently.
  • In most cases, hydroponically grown vegetation can be harvested in a time period 50% faster than their soil-grown counterparts. The extra oxygen in the growing mediums provides an extra boost to plants resulting in both expanded growth patterns and faster harvest rates. 
  • Hydroponic gardeners use significantly less time and manpower. The need for labor-intensive agricultural work isn’t needed in the same way for water-based systems. There is a need for overseeing the operations and harvesting, however, the use of labor isn’t equal to that of traditional farming due to automation and year-round climate-friendly environments.  

What Kind of Equipment is Recommended for Fast and Accurate Hydroponic Testing? 

Creating a successful hydroponic system hinges on the maintenance of four separate water components: pH, ORP, conductivity (EC), and temperature. For effective management of these components, adequate testing equipment is a must. 

There are products for every size set up, from the small-scale hobbyist to the large industrial type of operation. The prices will range from low to high and the scope of use might be different depending on the instrument type. Here is what you can expect to purchase for your water testing needs.

pH Testing Equipment: Sensors, Calibration Kits, Probes 

pH testing equipment, like pH probes, indicates the level of acidity within your system, but it can also tell you how your plants are responding to supplementation and if your water is too hard. Strips are inexpensive, but tedious and not that accurate. We recommend a sensor and probe combo adequate for small medium sized farms. They are inexpensive, accurate, and dependable.

Every crop has a specific pH range, so it is a good idea to keep a pH guide handy for normal ranges. Try to keep pH between 5.5 and 6.5 without changing more than .5 per day. You don’t want to throw your vegetation into shock. 

Buffering Solutions (increasing or decreasing pH levels) 

It may be tempting to save some money and reach for vinegar or lemon juice to temporarily lower the pH. This would be a mistake as they both can cause harm your plants. Neither element is stable over any length of time

Instead, use preformulated buffering solutions which won’t harm your vegetation or equipment. 

ORP (Oxidation Reduction Potential) Testing Equipment: Sensors, Solutions, Probes, Circuits

Sometimes referred to as REDOX, ORP is a measurement of the sanitizing (oxidation) power of oxidizers including chlorine, chlorine dioxide, and ozone. In plain terms, this tells you how well the organic matter is being processed(oxidation). 

The ideal chemical environment needs to have an ORP of above 600mV to eradicate fungi and bacteria. So, to keep a sterile hydroponic environment, you’ll want to keep the ORP of your nutrient solution in the 300-500mV range. This range is large enough to prevent the growth of unwanted micro-organisms, but also low enough to prevent root damage.

It’s recommended to have proper ORP testing equipment to accurately measure and optimize these levels in your hydroponics setup.

Temperature Testing Equipment: Probes, Calibration Kits, Circuits, Transmitters

The ideal water temperature for most plants is between 65- 72F. Temperatures can be affected inadvertently through light sources or changes in climate.  Some greenhouse farms have slightly higher temperatures but then they add chilling systems to help to keep it from getting too hot. 

Never add freezing or boiling water to your system as it can destroy delicate roots and throw plants into shock. Also, be wary of topping off the water with tap water or any questionable water source. Stick to tried and true water sources and test the temperature and other measurements before adding. 

The idea is to bring water levels up slowly while allowing the temperature and other chemicals to complex in the most natural way possible.  Conveniently, you can measure your water temperature accurately with temperature testing equipment like probes and circuits.

EC (Electrical Conductivity)

This is the measurement of electrical conductivity in your hydroponics system. More simply, it is the measurement of salts in your system. The EC is referenced to evaluate the amount of fertilizer used to provide nutrients to the plants. Experts recommend starting off with a low EC level and then scaling it up to meet the growth demands of the plant. The EC is expressed by siemens per square meter per mole (S/m2/mole) or millisiemens per centimeter (mS/cm).

Where Can I Source Hydroponics Equipment? 

Though it is easy to source pH and temperature testing equipment (they can be found in most pool, aquatic, or pet stores), going with the lowest cost option may not be a good idea. One of which is the ability to cross water platforms – from saltwater to freshwater. The other is the ability to give accurate readings and not having to worry about replacing instrumentation unnecessarily.

Some pH meters are only known to last one year or less, so in some cases investing in quality equipment might make more sense. Digital pH meters and sensors offer more control and accuracy, and many are designed to be multifunctional.

In some circumstances, completely automating your system with an embedded, Wi-Fi enabled Hydroponics Kit is the best way to go. It just depends on what type of system design you are using and what your goals are. 

When is the Best Time to Perform Hydroponic Water Tests and How Often Should I Do it? 

The best time to test is every time you top off your water and typically every three days. The best practice recommendations for testing EC and pH levels; therefore, it makes sense to add in the other components for testing I.e., temperature, minerals, etc. For volatile plant species or high dollar operations, we recommend testing daily and to consider an all in 1 device to make the testing process easier. 

How Do I Keep My pH from Fluctuating So Much? 

Even savvy growers have problems keeping their pH in perfect balance, so don’t beat yourself up too bad. Frequent fluctuation is rather common and there are several reasons why it may be happening:

1. When the nutrient solution drops below one gallon, the solution becomes more concentrated as plants absorb the nutrients. Your best bet is to keep the reservoir full and test directly out of the reservoir. 

2. Both inorganic and organic matter can have dramatic effects on pH levels. This happens because the growing mediums tend to act as a buffer causing pH levels rise. To get an accurate pH reading in a media-based system, test the pH of the reservoir solution as well as the water that drains through the mediums (leachate). 

3. Algae and bacteria are the main types of organic matter that affect pH levels. If pH levels rise in the morning and drop later in the day, algae may be the culprit. Algae consume acidic carbon dioxide during the daylight hours, so it is common to see pH levels spike, then abruptly fall as evening approaches.

4. Bacteria is a common cause of low pH levels. This occurs when diseased roots begin to rot; the bacteria will release acids into the hydroponic solution. 

How Often Should I Change My Nutrient Water Tank? 

Once the hydroponic solution ratio of top-off water equals the total volume of the tank then it should be changed out. Changing out the tank on a regular basis will prevent bacteria overgrowth. It is a really good idea to carefully observe your tank and take detailed notes. This is because changes in water chemistry can give clues such as noticing changes in odor, water clarity, plant vitality, or algae presence.

So basically, if you see green slime creeping within the tank walls, it is time to assess your water problem. All kidding aside, just be sure to keep a watchful eye on things, do your testing, and change and cycle your water when needed. 

Photo by Liz Harrell on Unsplash

Atlas Scientific for Hydroponics Equipment and Advice

While hydroponics isn’t exactly a plug-and-play type of gig, setting up and maintaining a flourishing hydroponics system is not going to send you to the crazy house – we promise. However, there are a few things associated with both new and established systems which may require some know-how and attention to detail.

We also know choosing the right equipment matters a great deal. It can make easy work out of an otherwise complicated job. Understanding how it all works and why it works is just part of the equation but having a source for reliable product offerings is the half that makes the difference. 

That is why we have team members are available for personalized advice and suggestions. Our goal is to help make hydroponics easy and accessible for you. Contact us today!

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