Hydroponic Growing in Drought Conditions

By Lacey Macri
Published: July 1, 2014 | Last updated: April 26, 2021 11:01:53
Key Takeaways

Want to conserve more water? Recirculating water in your growing system for longer periods of time carries a few risks, but by following the guidelines in this article, you can help respond to a growing water crisis.

Source: Panpote/

It is no mystery that California isn’t “keeping it green” in 2014. Early in the year, Governor Brown declared a drought state of emergency, urging residents and state officials to do whatever it takes to reverse this threat. Since then, there has been a plethora of rumors and regulations circulating within the state to help control water usage.


In May, the final snowfall report for the season was issued, yielding a meager 18% of the average snowfall compared to years prior. In June, CAL FIRE issued burn bans across the state to help prevent wildfire threats and conserve subsequent water usage. Issuing fines for using too much water has proven to be complicated and frustrating, to say the least, especially for the green thumbs out there.

Even if meteorologists are correct and we are in for a wet winter in 2014, we will still be playing catch up in order to be in the clear for summer 2015. Residential and commercial farming irrigation is responsible for a large part of California’s water consumption, and watering restrictions present a major obstacle for both commercial and hobby growers. To avoid being fined and to keep our gardens growing, we are forced to take actions of our own and find new ways to conserve water, both this season and in the years ahead.


Growing hydroponically does allow for a lot more atmospheric control, including water usage. The good news is those who use reservoirs to hydrate their plants are already conserving water, compared to those growing in soil and using an irrigation system. Reservoir water can be recirculated for weeks before it needs to be replaced with fresh water. Here are some tips to help you conserve water.

Change Your Water Less Often

Common knowledge within the hydroponic community suggests replacing your reservoir with fresh water every two weeks, but is this really necessary? If you live in California or anywhere else drought conditions persist, it may be a good idea to change your water less often. However, recirculating water for too long can increase the risks of your garden developing waterborne pathogens, nutrient toxicities and deficiencies, and an influx of pest infestations. But a keen eye, persistent attention, preventative measures and careful monitoring can help you conserve water and still avoid these issues.

Prevent Pathogens

Maintaining water health should be a priority for all growers, especially in hydroponics. Many pathogens, such as pythium, can wipe out an entire hydroponic crop quickly if left untreated. In field crops, pythium isn’t as serious of a threat because most of the cases are localized and do not spread, as the parasite tends to travel through water across distances.


Keeping the oxidation reduction potential (ORP) high is one simple way to help prevent potential harboring sites for pathogens. ORP refers to the sanitation of water and its ability to eliminate its impurities through oxidization. There are a few ways to test the ORP of your water source, including various ORP meters.

Once you get your ORP results, what are you supposed to do with that information? Studies suggest that water with an ORP of 680 mV or higher can kill pathogens in less than three seconds. Several products on the market can be used to push your water up to or above a level of 680 mV, creating an unfavorable environment for pathogens and reducing the odds of developing a problem.


Avoid Nutrient Toxicities and Deficiencies

Extending the life cycle of your nutrient solution means you need to monitor your nutrient levels carefully to ensure you aren’t developing any toxicities or deficiencies. Toxic levels of one nutrient can lead to deficient levels in others and vice versa. Also, watch for obvious symptoms of sick plants. These symptoms include but aren’t limited to slow root growth, discolored foliage, stunted vertical growth, wilting leaves and eventually plant death.

Monitoring EC and total dissolved solids (TDS) regularly helps to reduce the odds of developing toxic and deficient nutrient levels, but taking an even closer look at the individual elements may be necessary in certain situations. Measuring for TDS only tells you the total amount of nutrient concentration per million parts and provides no specific information on the individual ions that may be responsible for some of the symptoms you see. For example, both nitrogen and potassium deficiencies cause stunted growth, so how do you know which one is responsible for the problem in your nutrient solution? Getting a lab-quality report on your nutrient solution is the best way to be sure of what is in your water and what you need to do next to bring your plants back to health.

Prevent Pests

Maintaining a sterile environment for your plants to grow is the best way to discourage infestations. Pest infestations can lead to a number of other issues. If you experience a fungus gnat infestation, their feet can carry viruses that can easily be transmitted to your plants. Thrip damage not only produces obvious symptoms on the foliage of your plants, but also carries the risk of transmitting the wilt virus commonly found in tomato plants.

Once pests invade your growing space, harsh treatments may be your only chance to salvage your crop. Depending on the stage of growth your plants are in, it may be worth administering a pesticide. If you decide to go this route, frequent water changes must occur, especially if the plants are near harvest and you’re growing consumables. It is important to flush the plants with fresh water prior to harvesting to help prevent any health risks associated with the use of pesticides. Of course, organic growers face serious obstacles during infestations as they cannot use any non-organic products to combat the pests.

There are various products available to eliminate infestations, but maintaining a sterile environment is the best way to discourage unwanted inhabitants and prevent the problems in the first place.

Careful growing can help you achieve lengthier reservoir cycles, promote water conservation on a consumer-driven basis and hopefully contribute to putting an end to California’s water crisis.


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Written by Lacey Macri

Profile Picture of Lacey Macri
Lacey Macri works as head of sales at CleanGrow, focusing her time on business development within the company. She received a bachelor’s degree in communications and psychology from the University of California, Davis, in 2011, where she worked at the California Aggie student newspaper on campus.

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