Many assume that starting a hydroponics garden involves complicated electrical equipment, drip irrigation systems, and computers.
While the above may be the case for large-scale commercial hydroponic systems. This is not true for small-scale hydroponic gardens.
Beginner gardeners can start growing crops hydroponically with everyday DIY materials. Like a plastic tote bin, some fertilizer, and growing media.
Below, we will go over everything you need to know about the basics of hydroponics gardening. Advantages/disadvantages, and additional resources for getting started.
What is Hydroponics?
At its core, hydroponics is the art of growing plants without soil.
People assume that soil is absolutely necessary for plant growth, but this is not true.
Soil provides plant roots a structure to cling to. But this same support structure can be replicated with a variety of materials. Such as trellises in hydroponic gardening.
Essential nutrients are derived from the soil. These same nutrients can be supplied using alternative methods in hydroponic gardening.
In hydroponic systems, nutrients are dissolved in water and dispensed directly to the plant roots actively via tubes and pumps. Or more passively with a water tray and capillary action.
Essential microbial organisms are present in the soil, but again, these same microbes can live and thrive in hydroponic environments.
If soil is so essential for plant growth, why not just use soil?
Below, we’ll go over the advantages and disadvantages of growing crops without soil.
Advantages of Hydroponic Gardens
These are the key advantages of hydroponic gardening:
1. Grow Plants Anywhere Without Soil
This is a clear advantage, as many people, especially city-dwellers, do not have the luxury of large gardens. Others live in areas with poor soil quality not suited for edible crops such as the arctic or desert.
Hydroponics allows you to garden anywhere, even without any soil.
2. Fast Growth Without Restraints
Crops grown in soil rarely reach their full potential. They’re often constrained by factors such as access to water or nutrients in the soil. Roots may also become compacted or restricted, further limiting plant growth.
Hydroponics bathes the roots in a perfect blend of nutrients and water. Removing the constraints often found in soil.
3. Less Space
Plants spread their roots far and wide in the soil in their constant search for nutrients and water.
By growing plants hydroponically, roots do not need to spread as far to find nutrients. Allowing plants to focus on growing foliage and fruit.
This means the space is only limited by the canopy space and support structure provided.
Horizontal hydroponics systems allow for suspension and stacking. Vertical stacking systems allow for the construction of space-saving hydroponics garden towers.
4. No Growing Season Constraints
Growing crops indoors allows gardeners to prolong the growing season.
Even when placed outdoors, hydroponic systems can still extend the growing season. Root zone temperatures are often more important than leaf surface temperatures.
Hydroponic systems allow you to precisely control the root zone temperature. Permitting the growth of winter vegetables in hot summers and vice versa.
Hydroponic growers can control the root temperature with water heaters, chillers, or even burying the water reservoir underground.
5. Uses Less Water
Plants grown in soil lose a lot of water through evaporation and drainage.
Evaporation is reduced with hydroponic systems. As hydroponic plants are often kept in enclosed humid spaces such as a grow tray, a grow tent, or a greenhouse.
In hydroponic systems, water is also collected and reused. Reducing the need for wasted water.
6. No Weeding or Herbicides and Fewer Pesticides
Hydroponic growers never have to deal with weeds or herbicides. Focusing instead on preparing delicious dishes from their harvest.
Though pests do exist in hydroponic gardens, there are far fewer spaces for them to grow or hide.
When grown indoors with pest-control techniques, gardeners can almost virtually eliminate all pests.
7. Fewer Diseases, Pathogens, and Contaminants
Many pathogens such as root rot and bacterial wilt are soilborne.
With hydroponics, gardeners can quickly sterilize the system or replace the crop entirely at the first sign of pathogens.
Contaminants often found in manure or heavy metals found in rainwater are also virtually non-existent with hydroponics.
8. Control Crop Nutrition and Taste
A misconception is that the crops grown hydroponically are inferior in taste and nutrients to those grown in soil.
However, results from various studies are far more mixed.
Hydroponically grown crops can be equal to or better in nutrition than soil-grown crops under the right conditions.
A University of Nevada Reno study of strawberries and raspberries grown in soil vs. water showed that hydroponic strawberries and raspberries resulted in higher yields. Equal or better nutritional quality, and equal or better taste preferences. [1]
The consensus seems to be that factors beyond soil and water such as fertilizer, light intensity, irrigation stress, and temperature may affect crop taste and nutrition. Far more than just soil or water alone.
Fortunately, many of these factors can be carefully controlled within hydroponic systems.
Many hydroponic tomato growers, for example, will intentionally stress their plants at key stages to increase the sugar content.
9. Control Specific Plant Characteristics
Besides taste and nutrition, hydroponic growers can also influence certain plant characteristics. Such as leaf size, leaf color, root size, and plant height.
For example, indoor gardeners can adjust light color to induce certain plant characteristics. Blue light has been shown to create more compact plants and reduce the vertical space needed.
10. Cleaner and Less Labor
Every gardener who has tilled a garden can attest to the mess and amount of time required to prepare garden beds.
With hydroponic gardens, a lot of the messy preparation involving dirt is no longer required.
Automation is also possible with advanced hydroponics, reducing repetitive labor.
Disadvantages of Hydroponic Gardens
Despite all the advantages, there are a few key disadvantages to hydroponic gardens:
1. High Costs and Greater Learning Curve
Compared to traditional gardens, hydroponics can be an expensive investment. Especially if purchasing pre-fabricated and automated systems.
Learning to operate the system as well as researching the specific parameters for every crop can also take considerable time.
2. Requires Regular Maintenance and Monitoring
Growing crops hydroponically requires regular monitoring of factors such as lighting, temperature, nutrient, pH, and electrical conductivity.
The nutrient solution also needs to be flushed and replaced regularly. And the parts have to be cleaned to prevent clogs and buildup.
3. Waterborne Diseases
In hydroponic systems, water-borne diseases such as water mold and Pythium, a fungus-like microorganism, may attack crops. Water also helps these pathogens spread more quickly.
In extreme cases, a waterborne pathogen can infect an entire hydroponic system in a matter of hours.
4. Power Outages and Components Breaking
Hydroponic systems, both passive and active, require electricity to power the lights, water pumps, aerators, fans, etc.
Electrical and mechanical components in advanced systems may be prone to failure, and prolonged power outages may kill plants.
5. Harder to Scale
To maintain and operate larger-scale farms with hydroponics, investments in expensive systems such as computers or sensors may be necessary.
Personnel with deep knowledge of agriculture, plant physiology, chemistry, and computers are also required to operate these systems at scale.
Types of Hydroponics Gardening
There are many types of hydroponic systems and methods. With easier passive systems involving no pumps and more advanced active systems requiring electrical equipment.
Passive systems without complex equipment include the following:
- Bottle Hydroponics – This is perhaps the simplest method and involves using a bottle. For a water reservoir to feed the plants without soil.
A wick is often used to help pull moisture into the growing medium containing the seedlings.
Avoid clear bottles to prevent algae buildup. This method is ideal for growing herbs.
- Kratky Method – Popularized by Dr. Bernard Kratky of the University of Hawaii. The Kratky method is a passive hydroponic system very similar to the bottle method.
A container is filled with nutrient-rich water with a lid on top. The lid has a hole where a net cup can fit and be suspended without falling through.
Plants are placed inside the net cup filled with a growing medium. Such as stone/rock wool, coconut coir, coco peat, coco chips, perlite, peat, or clay pellets.
Allow the plant’s root tips to touch the top surface of the nutrient-rich water inside the container.
As the plant grows, it will drain the water, forming an air gap between the root and base of the plant.
By the time the nutrient water is depleted, the plant should be ready for harvesting.
- Floating Rafts – A floating raft hydroponic system involves using a rectangular raft that floats above a nutrient-rich water reservoir.
Holes are drilled in spaced rows directly on the floating raft. Net cups containing the seedlings and growing media are then inserted into these holes.
The raft containing the plants will float above the nutrient water. Capillary action will help roots and the growing media pull water from the nutrient reservoir below.
This system is ideal for shorter crops with lower root oxygen requirements. Air pumps may be installed to aerate the water.
Floating rafts are great for lightweight leafy vegetables. Like lettuce, kale, and spinach, which benefit from having unlimited access to water.
- Wicking Beds – This hydroponic system involves building a rectangular frame similar to a raised garden bed lined with waterproof material.
The first layer of the frame contains coarse aggregate material. Such as clay pellets, river rock, or washed gravel. This acts as the nutrient reservoir.
PVC pipes are inserted to allow water to flow through the first layer.
A burlap layer is then added to separate the aggregate materials from the second layer containing the media substrate above.
This growing media layer acts as a wick, using capillary action. Like a wet paper towel to pull up the nutrient-rich water from the layer below.
An additional burlap layer can be added as mulch. Cut the burlap when transplanting plants into the growing media.
Wicking beds are ideal for moisture-loving crops that have extensive roots. Like tomatoes, carrots, beets, potatoes, etc.
More advanced hydroponic systems involve pumps and tubes. That help actively circulates air and water. Greater aeration and nutrient circulation will help crops grow better.
Below are some examples of more advanced hydroponic systems:
- Media Beds – This method is quite simple and involves a large bottom water reservoir. In aquaponics, a fish tank is often used as a water reservoir.
Above the fish tank or water reservoir is a grow bed filled with expanded clay pebbles. From which plants directly grow.
A pump and drain system pumps nutrient-rich water from the reservoir below to fill the grow bed above. Before draining back down again repeatedly.
- Flood and Drain – Similar to the media bed system, this system also pumps nutrient water directly from a water reservoir into a grow tray before draining back into the reservoir.
In flood and drain systems, the grow tray contains individual pots filled with additional growing media. Such as clay pellets, coco, peat, and perlite.
Both media bed and flood and drain systems are ideal for vertical farming. Because the grow tray can be stacked, relying on a common water reservoir.
Flood and drain systems are ideal for microgreens. But larger pots can even be used to accommodate flowering crops.
- Top Drip – This method involves constructing a water pump that carries water from a nutrient-rich reservoir via tubes directly to the roots.
The main tube has branching tubes that allow water to drip out slowly. Similar to a drip irrigation system.
The branching tubes are placed directly above the net cup or pot containing the growing media and seedlings. An overflow tray may be placed below the containers to catch any water that drains out.
This method has many advantages. Like reducing water use, keeping leaves dry, and supplying roots with plenty of oxygen. The drip system also avoids flooding the roots.
- Nutrient Film Technique (NFT) – This technique involves constructing a series of sloped PVC pipes that are 4-15 ft (1.2 – 4.5 m) long.
Holes are drilled into the top of the pipes to accommodate small net pots. Which directly holds plants without any substrate.
Water tubes inside the PVC pipes pump a steady but shallow stream of nutrient-rich water from a common reservoir. This covers the roots of the plants in the net pot with a consistent film of nutrient-rich water.
This method is ideal for large-scale hydroponics. It does not require any substrates and uses minimal water. Pipes are also modular and expandable.
NFT systems are ideal for crops that love an unlimited supply of water such as lettuce.
However, they are less ideal for crops that have deep roots.Carrots for example, or crops that benefit from moisture stress such as jalapenos.
How to start a Hydroponics Garden for Beginners
As described above, hydroponic systems range from sophisticated systems requiring pumps and pipes to simple hydroponic garden DIY systems. Those do not require any electrical equipment or pumps.
Systems involving pumps are not necessarily more complex, but they do require some DIY construction.
Below, we’ll go over all the equipment you need to start a simple hydroponic garden without pumps. As well as basic equipment for an active pump-based hydroponic system.
What do you need for hydroponics?
The following are the basic components needed for both pump and non-pump hydroponic systems:
- Water Reservoir – Most hydroponic systems require a container of sorts that is filled with a mix of fertilizer and water (aka nutrient solution).
Reservoirs can be constructed from wood frames and plastic liners. Or they can be purchased or made from repurposed materials like plastic tote bins.
Reservoirs can also be as simple as plastic or glass bottles in simpler hydroponic systems.
- Nutrient solution – Nutrient solutions for hydroponics can be commercially purchased or self-mixed.
Specially formulated fertilizers for hydroponic gardens are required as regular soil fertilizers will rarely work in hydroponic gardens.
Hydroponic fertilizers can be as simple as mixing water with one, two, or three-part dry or liquid hydroponic fertilizers. Read labels carefully, as hydroponic fertilizers may be specially formulated for certain crops.
Some popular commercial brands include FloraNova Grow, FloraNova Bloom, Hort Americas, Hydro-Gardens, JR Peters Inc., and Plant Marvel.
- Growing Area – The growing area is a space for plants to grow. The area depends on the type of crop you decide to grow and the hydroponic system employed.
In nutrient film technique (NFT) hydroponic systems, the growing area is often just a net pot. Installed directly into the PVC pipes without any growing media.
With flood and drain systems, a growing tray is used to house container pots. Made of fabric or plastic filled with growing media.
In media bed systems, water is recirculated from the media bed. Where plants are grown directly in the grow tray filled with clay pebbles.
- Substrate and Growing Media – The media for starting seeds or growing plants can vary depending on the water-holding ability desired.
Clay pellets are very porous and may dry out quickly in a power failure, killing plants.
Other materials such as coco coir can go for days without needing irrigation. Materials that hold too much water may cause plants to grow more slowly.
Other popular growing substrates or media include stone/rock wool, coco peat, coco chips, perlite, gravel, phenolic foam, peat, rice hulls, river rock, sawdust, sand, or wood bark.
- Plants – Knowing which plants you want to grow can help you select the right hydroponic system. The flood and drain system works on a wide range of crops. While the bottle system works best for crops such as lettuce and basil.
For more advanced growers requiring active water dispensing, the below equipment is required:
- Water Pump – For those employing advanced systems requiring the circulation of water, height is usually the most important factor in selecting a pump.
NFT systems and vertical gardens require a more powerful pump to ensure greater flow rates.
However, all plants may benefit from a more powerful pump system. It’s far easier to reduce the flow of a powerful pump with valves than to increase the flow of a weaker pump.
- Air Pump – Air pumps help aerate and provide oxygen to the water. Plants without adequate oxygen around their roots may wilt.
- Tubing – Most hydroponic growers use black vinyl tubing for hydroponic irrigation. Clear tubing is not recommended as it may expose the nutrient solution to light, which causes algae buildup. Tubing is employed in hydroponic systems such as top drip and nutrient film technique (NFT).
- Flood and Drain Fittings, Grommets, and Tube Connectors – For those making DIY flood trays, fittings help drain and direct water. Grommets help form watertight seals around irrigation fittings. Tubing connectors help extend and direct water tubing.
- Net Pots and Trays – Net pots range from 2-10 inches (5-25 cm) and are used to house plants in hydroponic systems. Circular pots are the easiest to find, but square pots can help maximize space in square trays. Fabric pots are perfect for flood and drain systems because they dry and drain quickly.
- Grow Lights – Grow lights help seeds germinate into strong saplings. Plant growth and temperature can also be controlled with lighting systems and light color.
- Grow Tents – Grow tents help enclose your hydroponic system, allowing you to control lights, humidity, and pests.
- Measuring Equipment (pH, EC, etc.) – For more precise growers, measuring tools can help keep precise measurements. Electrical conductivity (EC) meters help measure the fertilizer or salt concentrations. Although not critical, pH meters can help diagnose nutrient deficiencies.
How to Set Up Hydroponics
For more information on setting up the hydroponic garden systems mentioned in this article, including detailed step-by-step instructions, refer to the book DIY Hydroponic Gardens by Tyler Baras.
The USDA National Agricultural Library also has a great resource page with even more information on hydroponic gardening. Including videos of each of the hydroponic systems described in this article. [2]
Best Hydroponic plants
The best plants to grow in hydroponic systems are those with shallow roots. That benefit from an unlimited supply of water such as the below:
- lettuce
- strawberries
- blueberries
- spinach
- kale
- bell peppers
- herbs such as basil, chives, oregano, coriander, etc.
- all microgreens
Other flowering crops can still be grown hydroponically, but require some extra attention:
- tomatoes – make sure they have enough lighting and support structures such as trellises
- hot peppers – jalapenos and habaneros do well hydroponically but require moisture stress to increase the spiciness
- tubers – tubers have deep roots, so select a system that allows their roots to grow without constraint
Hydroponic garden vs. Soil
The main difference between a hydroponic garden and a soil garden is that crops grown hydroponically grow a lot faster without the constraints of soil.
Hydroponic gardens also allow gardeners to grow crops anywhere, regardless of the availability of soil. Crops grown hydroponically also take up less space and are also not bound by the growing season as tightly.
Hydroponic crops also use less water than those grown in garden soils. Without soil, crops also experience fewer soilborne diseases and pathogens.
References:
[1] Baras, T. (2018). DIY Hydroponic Gardens: How to Design and Build an Inexpensive System for Growing Plants in Water (1st ed.). Cool Springs Press.
[2] Author unknown, (n.d.), Hydroponics. National Agricultural Library. https://www.nal.usda.gov/farms-and-agricultural-production-systems/hydroponics.