7 Essential Tips for Keeping Hydroponic Plants Alive


Hydroponics is a farming technique that doesn’t require soil. Instead, you utilize a soilless medium while suspending the plants’ roots in a steady supply of water and nutrients. As more people learn about the benefits of hydroponics, it’s becoming increasingly popular.

Here are 7 essential tips for keeping hydroponic plants alive:

  1. Use quality water.
  2. Use the right nutrients.
  3. Choose the right growing medium.
  4. Choose a good grow light.
  5. Consider environmental factors.
  6. Increase the availability of oxygen.
  7. Clean, calibrate and hydrate your meter’s probes.

In this article, I’ll discuss essential tips on growing plants using hydroponics. Read on to learn how to keep your hydroponic plants alive and healthy.

1. Use Quality Water

A hydroponic system depends on water as much as traditional systems rely on soil. As a result, poor quality water will negatively affect the plants. If you’re using your own water to grow hydroponic plants, you’ll benefit from determining its composition by paying for lab analysis.

The more you know about your water’s composition, the better you can treat or manage it to meet your plants’ needs.

Why the Water Quality Matters

If you read many growers’ forums, you’ll most likely come across a discussion on the benefits of using RO (reverse osmosis) water or caution against the use of municipal water. These discussions might be difficult to follow if you don’t understand water’s role in hydroponics. 

The quality of water can either make or break your hydroponics system. If the water is contaminated, this can cause a broad spectrum of problems, from reducing the nutrient uptake by plants to increasing the invasion of pathogens.

To avoid this, first, check whether the water in your system is pure. This means its EC (Electrical Conductivity) value should be 0 (or very close) and have a pH value of 7.0.

There are very few pure water sources, especially in urban areas. Hence, you should establish a water monitoring and treatment program for your hydroponics system. This will enhance the water’s ability to hydrate and transport essential nutrients and minerals to your crops.

When you’re aware of your water’s quality, you can determine the level of treatment required to get it to its purest state.

I’ll cover more about water sources, testing, and treatment methods a little further into this article.

2. Use the Right Nutrients

In hydroponics, you provide your plants with all the nutrients they require, including the ones they’d be getting from the soil. As a result, you must be well conversant with all the nutrients you choose to use. Adding the wrong mix could affect your plants’ health or even kill them.

Nutrients are so important in hydroponics since the plants exclusively grow in water. Some gardeners use soilless mediums, like coconut fiber, cocoa, and stone wool, for certain plants, yet they still transfer them to water containers once seedlings are old enough. As a result, hydroponic plants get all their nutrients from the nutrient-rich aqueous solution.

In fact, plants grown in this system require more nutrients than conventional growing methods. This is because soil provides some naturally occurring nutrients which are absent and need to be provided in hydroponics.

As you add nutrients to your hydroponic system, keep in mind that they affect the pH level of the water. For this reason, it’s advisable to have a pH meter at hand to check the pH levels of the water once you’ve added nutrients.

Nutrients Used in Hydroponics

Plant boosters and organic nutrients are the basic types of nutrients required for the growth of plants:

  • Plant boosters: These boosters are relatively new in the market and can help the plants absorb the nutrients infused in water and significantly improve growth. There are also plant boosters for speeding up the flowering of plants. However, gardeners should only use these advanced concoctions under the guidance of an expert and only for a sizable garden.
  • Organic nutrients: Organic nutrients are composed of nutrients essential in hydroponics used in organic gardening and should be free of material that can form deposits. Substantial particles cannot be absorbed by the plants and can actually pile up and clog the hydroponic system.

How To Purchase Nutrients for Hydroponic Gardens

Hydroponic kits are available online and in physical stores. However, it’s advisable to buy them from proper retailers to get detailed information on their composition and usage. Furthermore, you should apply hydroponic nutrients correctly for optimal absorption.

Once you select a plant nutrient, stick to it because changing the brands and types repeatedly is unhealthy for the plant. Apply nutrients for indoor hydroponic vegetables systematically for the correct uptake by plants.

While shopping for organic nutrients, you should first understand the combinations. For example, all hydroponic plants require a mix of macro and micronutrients. The macronutrients form the basis for the plant’s nutrition and should be added throughout the year. These include:

  • Oxygen
  • Nitrogen
  • Magnesium
  • Phosphorus
  • Sulfur
  • Calcium
  • Hydrogen

Micronutrients, on the other hand, are needed in small quantities occasionally. They include cobalt, iron, manganese, nickel, molybdenum, chlorine, silicon, zinc, and sodium.

3. Choose the Right Growing Medium

The basic concept of hydroponics is to replace the soil with other substrate materials to anchor the plant. As a result, the growing medium you choose acts as your plants’ soil. The most suitable medium for you will depend on your hydroponic system’s design, location, and scale. Here are some factors to consider as you look for a growing medium:

  • Is it easy to pot-up and handle?
  • Is it available in your region?
  • Is it affordable?
  • Does it provide good medium-to-seed contact?
  • How is it affected by temperature?
  • What is the Cation Exchange Capacity? (This is its ability to release cations, or positively charged ions.)
  • What are the material’s recyclability and reusability?

All these are important questions you need to ask before settling on a hydroponic growing medium. You should also start small and experiment with different media before choosing which one to pick and scaling up.

Common Growing Media

Here are some common growing media to consider:

  • Coco coir: Made from the outer husks of coconuts, this by-product of the coconut industry is sold as blocks, plugs, or slabs. It’s highly absorbent and keeps water well between irrigation cycles.
  • Gravel: This is a cheap, easily obtainable, easy to clean, and well-drained medium. However, it’s rarely used because of its inability to absorb moisture.
  • Grow rocks: Also known as expanded clay pellets, grow rocks are available in various sizes from 1 to 18 mm (0.04 to 0.71 in) in diameter. They have tiny air pockets for excellent aeration and drainage and can last for many crop cycles before finally breaking down. Keep in mind, you must manage diseases if the rocks are reused.
  • Perlite: This granular substance originates from volcanic activity and comes in several grades for crop propagation or starting seeds. It works great alone or combines with other media in a soilless mix. Perlite is lightweight and has excellent wicking, thus provides excellent aeration for the plant roots.
  • Hemp fiber: Mats made from clean and decorticated industrial hemp fibers are biodegradable and compostable. Hemp’s water holding capacity also makes them perfect for germination and root formation.

4. Choose a Good Grow Light

Another important aspect of hydroponics growing is the light source. Since most hydroponics gardens are indoors, it’s crucial to utilize a reliable grow light to provide your crops with as much light as they’d be taking from the sun. With the right knowledge, anyone can take advantage of modern LED lights and grow hydroponics indoors.

Here are some of the best types of grow lights you can get in the market today:

Fluorescent Lighting

Fluorescent grow lights are the best types of lights to use when planting the seedlings. The light bulbs release a pale blue color. Therefore, their low heat won’t scorch the young plants, allowing them to grow quickly.

Fluorescent lighting has a wide range of light and dispenses evenly to all your plants, facilitating uniform growth. They’re rated between 20 and 60 watts and available in 12 in (30.48 cm), 24 in (60.96 cm) and 48 in (121.92 cm) sizes. 

LED Lights

These are the most recent and most impressive grow lights in the market. Thanks to technological advancements, they’re cheaper than ever before and very cost-efficient. Plus, numerous options can be found, including bulbs that emit blue, red, white, or pink lights.

Although LEDs are significantly more expensive than other grow lights options, they make up for it with efficiency and a long lifespan. 

High-Pressure Sodium Bulbs (HPS)

HPS bulbs provide an orangy-red hue. They’re ideal for when plants or vegetables begin to flower. However, while they’re inexpensive to buy, HPS bulls are also extremely bright and known to generate a lot of heat, which might not be good news for your power bills.

5. Consider Environmental Factors

Environmental conditions can significantly affect your plants’ health. Moreover, environmental factors are usually intertwined. Therefore, when one factor fluctuates, the rest won’t achieve their desired effect. 

Here are some of the most critical environmental factors to consider in hydroponics:

Atmosphere 

The grow light you choose is as essential as the atmosphere inside your grow room. Plants can survive in a poorly lit environment with the proper atmosphere. However, they won’t grow in a room containing a strong grow light but with an unconducive atmosphere.

Temperature

It’s important to ensure temperatures don’t vary significantly during day and night cycles. Maintaining the optimum temperature range helps to limit the risk of mildew and mold build-up. Remember, plants have varying temperature requirements for growth. For instance, a young plant doesn’t have fully developed roots and needs higher temperatures to acquire additional moisture from the air through its leaves’ stomata. 

Humidity 

Humidity is the amount of water vapor (moisture) in the atmosphere at a specific temperature. It can affect plants’ uptake of nutrients and their growth. For instance, if the humidity is too low, the insufficient moisture causes plants to absorb excessive nutrients. This can result in nutrient burn, leading to wilted leaves with scorched edges. Contrastingly, high humidity can encourage mildew and mold.

Ventilation

Another environmental factor to consider is ventilation, which you can use to regulate humidity in your grow area. Plants get rid of excess moisture through transpiration. Without proper ventilation, moisture accumulates, increasing the room’s humidity. This can encourage mold and mildew. Apart from increasing ventilation, it’s advisable to irrigate your plants with the grow lights on, to facilitate the evaporation of excess water.

Carbon Dioxide

If you’ve incorporated MH/HPS or LED grow lights into your hydroponic setup, you can consider CO2 supplementation to boost productivity. The addition of CO2 in a sufficiently-light grow room facilitates more light absorption by the plants. Consequently, the rate of photosynthesis will increase, resulting in higher yields. 

Still, CO2 is denser than air. Therefore, it’s essential to use an oscillating fan to distribute the CO2 evenly throughout the room. Also, don’t supplement CO2 at night, because plants don’t carry out photosynthesis then.

6. Increase the Availability of Oxygen

Oxygen is essential for both animal and plant health. In nature, plants draw oxygen from the environment through their roots and leaves. In hydroponics, an artificial environment is created, so oxygen must be available at the plants’ roots. This can be done by adding oxygen to the water used to provide nutrients.

This is enabled using air stones, air pumps, bubblers, or an air gap. In addition, your water’s temperature affects oxygen availability. Generally, cold water holds more oxygen while warm water holds less. You should try to keep your growing water around 18-22°C (64.4-71.6°F).

Some hydroponic gardeners add hydrogen peroxide to their reservoirs to increase oxygen. Although, this might provide oxygen in a way the plant can’t access.

7. Clean, Calibrate and Hydrate Your Meter’s Probes

As emphasized throughout this article, your water’s pH level, temperature, and EC are essential in hydroponics. Therefore, hydroponics growers buy probes or meters to test their reservoirs’ level of each of these parameters. You can get these probes online or in brick-and-mortar stores.

One essential thing to remember is that probes require good maintenance to give accurate readings and long service. Here are some things you should do to keep your probes in good working condition:

  • Keep them hydrated: Dry pH probes, for example, are less accurate than hydrated ones. As a result, you should keep your probe in a KCL solution for at least 4 hours before using it.
  • Clean them: When you measure the pH, temperature, or EC value of your growing water, the probes are exposed to many microorganisms and contaminants. Therefore, it’s important to clean them when you’re done to retain accuracy.
  • Don’t test solutions that react with glass: Although glass is mostly unreactive, it’ll react to some chemicals, especially strong bases. For example, if you test a solution with a pH value of more than 10, the probe will start reacting with it and losing its calibration.  

What Is Pure Water and What Are Its Benefits?

Pure water comprises equal parts of the hydroxyl (OH-) ion and hydrogen (H+) ion and has no impurities. The balance between these ions produces a perfect pH value of 7.0. Pure water is beneficial because it lacks microorganisms, contaminants, pathogens, or minerals.

Pure water is the most ideal for use in hydroponic systems. Since it’s contamination-free, using it minimizes the chances of pathogens affecting vital aspects of your hydroponics unit.

Here are other reasons why it’s recommendable to use pure water in hydroponics:

  • It lacks minerals or unwanted salts: Some naturally-occurring minerals (or salts) can alter the dissolution ratios of nutrients added in a hydroponics system. Minerals such as sodium will disrupt how vital nutrients like potassium dissolve in water, causing nutrient deficiencies. However, since pure water doesn’t contain these disruptive minerals (ions), essential nutrients will dissolve optimally for uptake by plants.
  • It lacks toxic components: A hydroponics system may contain beneficial microbes in the soilless medium or other biological control organisms. Pure water has no harmful components that could risk the survival of these vital organisms. Hence, they form an integrated pest management program (IPM).
  • It has no physical, chemical, or biological contaminants: When adding nutrients, contaminants could react and form an insoluble precipitate that’s unavailable to the plan. Thus, it’s safer to use pure water.
  • It has no pathogens or insoluble matter: These can interfere with water disinfection treatments.

Types of Source Water

Source water is the available water reservoir for use in your hydroponics system. Some sources offer more pure water than others. Although you might not choose the source of your water, it’s crucial to know each of its features, benefits, and drawbacks.

Several water sources are available for crop irrigation. They may be natural sources like rainwater, surface water, and groundwater or artificial sources such as city or municipal water.

So, let’s have a closer look at each source:

Groundwater

The first source is groundwater. It comprises water from natural resources, including streams, ponds, rivers, or dams. Although you can use it for irrigation, if untreated, groundwater may adversely affect your hydroponic plants. 

This is because it may contain organic matter or pathogens. Additionally, the presence of dissolved minerals such as calcium carbonate may alter the pH, lowering the water quality. There are also higher chances of finding contaminants in groundwater resulting from chemicals used in farming, industries, or waste disposal.

Rainwater

Rain is perhaps the most known water source. It’s often considered the best water for crop irrigation. Rainwater is mostly pure, except for the presence of negligible atmospheric gasses. However, when it collects from roof structures, it could contain contaminants like lead and asbestos.

Domestic or Tap Water

Most households receive water from the municipal or city suppliers. But, its quality mainly depends on the specific source and if it has undergone treatment. 

Many city suppliers treat the water running in your taps through desalination or filtration. In most cases, they also add chloramine or chlorine to get rid of pathogens. So, even if the water is safe for drinking, these elements could slow down your plants’ growth cycle or impact some of the microbes in a hydroponics unit.

Regardless of which water source you use, testing it regularly helps enable you to determine its quality and treat it accordingly. You can do this by constantly checking its pH and electrical conductivity (EC) values. The closer the pH value is to 7.0, and the EC value is to zero, the better.

Characteristics of Untreated Water

As we’ve seen, untreated water can have numerous adverse effects on your plants. Apart from reacting with the microbes in your growing environment, untreated water can be salty or acidic, which can affect the quality of your produce. 

Here are some characteristics of untreated water:

Salinity 

Untreated water often has different types of salts, including sodium chloride, bicarbonate, and carbonate, that affect the availability of water to your plant. While most of these salts are actually essential plant nutrients, excessive amounts could be toxic. To avoid this, you can measure your source water’s EC and have an idea of its salt concentration.

Water Hardness

Untreated water is often hard, which means it’s rich in minerals – typically magnesium and calcium. A high concentration of these minerals causes a nutrient ratio imbalance when adding a nutrient mix. 

Calcium also facilitates the build-up of calcium sulfate precipitate, which can cause equipment blockage. A nutrition mix for hard water can help. But, it’s not a guaranteed solution if you aren’t aware of the accurate mineral composition of your water.

Alkalinity

Alkalinity and acidity has everything to do with pH. Alkalinity means your source water is high in alkaline bicarbonates and causes the pH value to rise. You can fix this by adding acid to neutralize it, but it might be challenging to get the optimal level for nutrient availability if the concentration is too high.

Common Methods of Water Treatment

Using untreated water in hydroponics can have negative impacts on your plants.

Here are the most common ways to treat the water you use for your hydroponic plants:

  • Reverse Osmosis (RO): RO is the most commonly used water treatment method in hydroponics. The process involves using a semi-permeable membrane in removing unwanted nutrients, ions, molecules, and large particles from water. However, RO isn’t effective in getting rid of harmful microorganisms or pathogens.
  • Deionising: It’s a process that utilizes ion exchange membranes to remove all the charged ions. It doesn’t remove microbes or pathogens but clears unwanted nutrients and elements. 
  • Ultraviolet (UV) light treatment: Using UV rays is a chemical-free method of disinfecting water. The UV light eliminates microorganisms like viruses and bacteria from water supplies. However, UV light might negatively affect plants, people, or animals. The method also doesn’t remove minerals (ions) and other contaminants.

Testing Your Source Water

As we’ve established in this article, testing your water is a vital part of making sure it’s the right quality. You can send samples to a laboratory and have technicians verify their quality. Yet, the easier option – and the one most people go for – is to measure it yourself using these fundamental tests:

  • Electrical conductivity (EC): There are no electrical-conducting elements in pure water. Therefore, its EC value must read zero. Testing your water’s EC value can determine whether it contains any impurities that could alter your calibrated hydroponic system.
  • pH: Ideally, pure water should have a pH value of 7.0. As indicated earlier, bicarbonates may cause the pH value to rise. Therefore, a high pH value van indicates the presence of contaminants.

Furthermore, these are the best times to test your source water:

  • Before adding nutrients: Nutrients aren’t cheap. It’s great to measure the water’s quality before adding nutrients to avoid adding something already there. However, it’s also important to know what the water contains before adding nutrients. The addition could potentially react and form a precipitate, which would have toxic effects on your plants.

After your nutrients have run through the hydroponic system: This is another excellent time to test the water’s quality, just keep in mind that you won’t be testing the water alone.

Alexander Picot

Alexander Picot is the principal creator of TheGrowingLeaf.com, a website dedicated to gardening tips. Inspired by his mother’s love of gardening, Alex has a passion for taking care of plants and turning backyards into feel-good places and loves to share his experience with the rest of the world.

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