Hydroponics and aquaponics sound about the same. After all, they both have water in their name and we grow plants using both systems. They share similarities and have a few differences, but you may be surprised at how simple these techniques can be.

Hydroponics and aquaponics can seem like complicated systems best left to professionals. After all, most of the lettuce we buy at the store, along with much of our other produce, is grown hydroponically. Huge greenhouses acres in size with state-of-the-art computer monitoring systems, climate controllers, precision fertilizer applications, and trained staff replicate exact crop standards cycle after cycle. But what if I told you that hydroponics can be as simple as growing three heads of lettuce in a five-gallon bucket? 

These practices don't have to be complex or expensive, and an entire body of research at universities has proven the feasibility of home-scale hydroponic and aquaponic systems. Some systems don't even require electricity. 

What is Hydroponics?

The USDA explains hydroponics as "the technique of growing plants using a water-based nutrient solution rather than soil, and can include an aggregate substrate, or growing media, such as vermiculite, coconut coir, or perlite." That boils down to growing in water and providing the plants with everything they need, all the macro and micronutrients, via the water they are growing in. 

Plants need light, water, air (both carbon dioxide and oxygen), and nutrients to grow. In a traditional garden, these needs are provided by nature and possibly enhanced by the gardener. Light is provided by solar radiation (the sun), they receive rain or irrigation, carbon dioxide and oxygen are present in our atmosphere and the ground, and the nutrients come from the soil. In hydroponics, the grower supplies most of those needs. While that might sound tricky and cumbersome, it's actually pretty slick. 

Now, I'm not knocking growing plants in the ground. In fact, I still feel that is often the simplest and easiest way. But, it isn't always practical. Gardening space can be hard to find, and not everyone has access. Contaminated soil or a lack of soil can be problematic and expensive to overcome. For those of us in northern climates, outdoor growing seasons are short. And soil-borne pathogens can make growing some crops like tomatoes tough. Hydroponics offers many benefits and can overcome some of these problems.  

Hydroponics Benefits

• Grow all year round.
• Increased growth and yields compared to traditional soil-based growing.
• Requires little space–perfect for people without access to large outdoor areas for gardening.
• It can be as simple or elaborate as your designs and budget allow.
• Fewer issues with soil-borne pathogens and pest insects.
• Greater control over inputs.
• Grow even where traditional soil-based methods won't work, like urban areas or contaminated soil.
• Uses less water than traditional methods.
• And of course, no weeding!

What can I grow in a hydroponic system?

While some crops are more suited to hydroponics than others, many crops typically grown in the garden are well-suited for hydroponics. Leafy greens like lettuces and spinach are perfect 'starter' plants to learn the ropes and can be repeatedly harvested. They are rather forgiving and won't be a flop if conditions are not perfect. 

But other popular choices including tomatoes, peppers, cucumbers, strawberries, herbs such as mint and basil, and other greens like mustard, kale, and Swiss chard are all very doable. While the sky is virtually the limit, growing pumpkins in your kitchen is probably a challenging choice. Pick plants that fit your space and the size of your system.

What is Aquaponics?

To oversimplify things, aquaponics can be thought of as hydroponics with fish. If you are just growing fish in a tank, it's fish farming. If you are growing only plants in water, it's hydroponics. Together, they yield an entirely new venture–aquaponics. While aquaponics can be as simple as growing a basil plant over your aquarium, the systems typically get more complex. It requires caring for the needs of both the plants and the fish, two entire sets of knowledge, and then successfully blending the two into one system. The fish supply some of the nutrients for the plants, and the plants filter the water for the fish.

Aquaponics practitioners can grow ornamental fish or fish for the table, like catfish, trout, tilapia, and prawns. It's a fascinating rabbit hole to dive down, but due to its increased complexity, we'll talk more about hydroponic systems for home gardeners.

Home-Scale Hydroponic Systems 

If the upcoming winter has you already missing fresh lettuce or pondering how to keep fresh herbs in stock, a small hydroponic system could be the perfect winter diversion. 

You'll need to test the pH of your water, which can be easily done with inexpensive test strips. Most plants will grow well with a pH between 5.5 and 7. If your water is outside those numbers, adjust it with baking soda, citric acid, or products sold at hydroponics stores and websites. Chlorinated municipal water can be left to sit out at room temperature for a few days to allow the chlorine to dissipate.

With the exception of carbon, hydrogen, and oxygen, you'll need to provide all of the plant's other macro and micronutrients. Many trace elements, like zinc, copper, sulfur, and molybdenum, are present in the soil but not in your water source. Premixed hydroponic fertilizers are widely available and solve the problem for you.  

The following two common hydroponic systems are inexpensive and easy for home gardeners to build (or purchase) and operate. Even a relatively small system can provide a continuous supply of fresh veg and herbs all year. 

*** In any hydroponic system, algae growth in the water can be a problem. To limit or prevent algal growth, use containers that don't allow light through instead of clear plastic or glass. 

Deep Water Culture

Deep Water Culture, or DWC, is one of the simplest methods. If you'd like to try hydroponics without building or buying an elaborate system, check out DWC. 

You’ll need the following equipment:

• A container to hold water–an inexpensive tub or a five-gallon bucket works fine. 
• A lid or cover which holds the plants above the water level. 
• A light source if growing indoors.
• Net pots or similar containers to hold the plant. 
• Substrate to support the plant. Typical choices include perlite, clay pebbles, coco coir, or even gravel.
• Nutrient solution.

DWC growing setups can be created with materials from your local store in an hour or less. If growing outdoors, like on a balcony or deck in the sun, you won't even need supplemental lighting. Holes in the lid support the net pots, which hold the substrate and the plant. The roots grow into the water and receive oxygen from the portion of the roots hanging above the water and in the netting pot. Seedlings can be started separately or even planted right into the net pots in a Jiffy pot or similar seed starting pod.

Nutrient Film Technique

Often referred to as NFT, this system uses a tube or trough with a constant film or flow of nutrient solution over the roots. Plants are held in net pots via holes in the tube or trough. Typically, a slight downgrade helps the system to flow from top to bottom. If you've seen a small tower built of PVC piping with plants growing along the pipes, it's an NFT system. A small pump pushes the nutrient-enhanced water from a reservoir up to the top, and gravity brings it back down. NFT systems are very popular with home gardeners and can be built DIY or purchased as a kit.