Hydroponics is growing more and more popular among home gardeners and self-sufficient lifestyle enthusiasts, and for good reason. You can grow more herbs, veggies, and fruits in a smaller area and with far less water using hydroponic systems than you can with soil-based techniques. Because you are growing in a closed environment, you don't have to use any pesticides. While you may be limited by seasons and agricultural zones using traditional methods, hydroponics lets you choose to essentially sprout when you want, what you want and wherever you want.
If you are new to the hydroponics world, it's easy to be overwhelmed by the wealth of choices. We're making the decision easier by laying out the difference between the systems so you can pick the one that works best for you.
The Basics of Hydroponic Systems
In order to decide on the method that works for you, it's important to understand the basics of how hydroponic systems work. If you want a little more basic information on hydroponics, check out our beginner's article.
A substrate is a material that you will use to anchor your plant's roots. Since hydroponic systems don't use soil, you'll need to replace it with an inert material that is able to retain moisture, foster aeration and provide support. Types include peat moss, clay pebbles, coconut fiber, oasis cubes, growstones, and lava rocks. Some systems don't need a substrate at all.
Deciding which system to use can come down to which substrate you want to deal with, or if you want to forgo them altogether.
Providing the right nutrient mix is essential in hydroponics. Since there is no soil, the plants depend on you to deliver precisely what they need to survive. You can make your own nutrients, or you can buy commercial nutrient solutions.
Consequently, one of the disadvantages of hydroponics over soil is a greater need for grower management. Some systems are simpler than others, so you'll want to factor in your knowledge and the time that you are willing to dedicate to managing your plants.
You will frequently need to test your nutrient solution to make sure it is the right pH for your plants. pH affects how well the plants are able to take up nutrients.
You also need to keep an eye on oxygen levels and temperature. Some systems require that you change the water, maintain equipment or clean frequently to stave off mold or parasites.
When choosing a hydroponic system, keep in mind your time and willingness to commit to maintenance.
Types of Hydroponic Systems
Now that you understand the basics, it's time to dive into the various types of hydroponic systems. There are six types of hydroponic systems with many different variations. They are the basic wick system, deep water culture, ebb and flow, drip, nutrient film technique, and aeroponic.
1. Basic wick
This is the simplest of all the hydroponic systems. You don't need any complicated moving parts like a pump or electricity, which makes it an ideal starting point for people who are just learning how to use hydroponics or who don't want to worry about electricity failures ruining their crops.
This is also a good system to do at home on a small scale. Basically, it is a container holding plants on top of a container holding a water and nutrient solution. The plant containers sit over the box containing water and your nutrient mix. A wick, just like in a candle, goes from the plant onto the water.
All you need to get going with a wick system is a container for the plant, a container for the water, a wick and a growing substrate.
To build this system, you fill your growing tray with a substrate. You can use several types of growing mediums for this type of system. Vermiculite, coco coir, and perlite work well because they have good wicking abilities without becoming overly soggy and wet.
Below this, you'll need a container filled with water and the nutrients your plants need to thrive. You will connect the grow tray and the water tray using wicks. Most beginners use a cotton rope as the wick, or you can use nylon. The larger the system and the more plants you have, the more wicks you will need to move the water to the plants.
This is a simple hydroponic system that you can get started with little experience and for little cost. The wick system makes an easy Do It Yourself project.
There are several drawbacks to the wick system, the biggest of which is the fact that it just doesn't work well for large plants. Big plants are too thirsty for the amount of water that the reservoir can supply. These systems are also less efficient than some others at delivering water and nutrients.
Finally, the wick system doesn't distribute nutrition evenly. Nutrients can build up in the soil, so you need to flush the system about once a week to make sure that your plants aren't being overwhelmed.
The wick system works best for plants that don't need a ton of water, and that stay relatively small. Thirsty plants like tomatoes don't do well in a wick system.
2. Deep Water Culture (DWC)
This hydroponic system is the simplest one that involves moving parts and is often used in classrooms. I used this process in my Middle School Science class, and the kids had so much fun that they willingly ate lettuce!
Plants are held in place with a styrofoam or plastic platform, or a raft suspended into the water. An aquarium air pump is put in the water to supply oxygen to the roots of the plants.
To make this system work, you need a water reservoir. Many people use an old aquarium for this part. You also need an air pump, air stone, tubing, growing media and, of course, your plants. Check out an aquarium supply or pet store to buy supplies for this system.
This method doesn't require a substrate, although you can use one if you want.
This lettuce raft makes a great DIY home project. The lettuce raft works well indoors, and you can even add a couple of goldfish to the mixture.
This hydroponic system is an excellent way to get started because it's less expensive to make and easy to build than some others. It's also simple to maintain, with little work once you have it all set up. Some plants thrive particularly well in this type of setup. Greens work great because they like their roots to be wet and they fast – some greens will grow twice as quickly as they would in the soil.
Small systems like the DWC tend to have a considerable fluctuation in pH and nutrient concentration. This system relies on electricity, so you risk losing your plants if you lose power. Larger plants such as tomatoes and cucumbers do not do as well in this setup.
Plants that will thrive in a DWC are those that are light so they won't weigh down the raft, and those that can be grown in a compact space. You also want to select plants that like a lot of water and don't need good drainage.
- Collard Greens
- Bok Choi
3. Top Feed (aka Drip System)
This system does have some mechanical parts so is a bit more complex – but not that hard. This system is used in many professional hydroponics operations.
The drip system is similar to the wick system with two boxes, one on top of the other. In this system, instead of a wick drawing up water, a pump circulates the water. A timer controls a small submerge pump in the water. At timed intervals, the nutrient solution is pumped up onto the plants.
There are two variations on this system: Recirculating and non-recirculating. In the recirculating system, the excess nutrient solution drips back into the tank, thus preventing waste. As the name implies, the non-recirculating system dumps excess water.
To get going with this hydroponic system, you need a container, a reservoir, a pump, a timer, tubing, and a growing media. Rock wool, coco coir, rocks and vermiculite mix all lend themselves to this type of system.
Not too expensive to build, this system has a lower chance of failure than some others. You can also scale this setup easily so you can expand from growing a few veggies to a whole crop as your needs and experience dictate.
This system is more complex, and it can require more maintenance to keep it going if you plan on recycling the water. That's because the recycled water can quickly build up an excess of nutrients. If you opt for a non-recirculating system, you will waste a lot of water keeping this type of setup running.
This system works well with a vast variety of plants, including larger plants like squash that might get too big for other hydroponic systems. That's one of the reasons it is so popular with commercial and large-scale growers.
4. Ebb and Flow (aka Flood and Drain)
This intermediate hydroponic system is one of the most versatile. The basic concept is that you fill a tray with plants and then periodically flood the tray with water and nutrients. The water returns to a reservoir below using gravity. It doesn't need much water or electricity to function, but it can be a little daunting to new users.
To setup, you need a flood tray sitting on a stand inside a reservoir. A pump sits in the reservoir to force water into the tray a couple times a day. You'll also need a screen, a growing medium and some tubing for the water to run through.
Because plants are immersed in flowing water for a time, it's important to pick the right medium for this system. Perlite can be too light, which allows plants to float or tip over. Heavier mediums like rockwool or coco coir work best.
Plants love this system because it encourages healthy root growth. Since the draining water sucks oxygen into the growing medium, it also gives plants plenty of oxygen. You can grow larger crops using this method that wouldn't thrive in some of the smaller systems.
This can also be a low-cost method that is easy to maintain, but there are sophisticated systems out there that will run you a pretty penny.
You have to be diligent about cleaning this system or you risk mold and insect infestations. Because the water is rushing in and out, the pH of the plant medium can change dramatically. Sensitive plants don't like this. You can also experience salt build-up using this type of hydroponic system.
Like any other system that relies on electricity, if your pump fails or your power goes out, you risk losing your crops.
This system works well with a variety of plants, but particularly those that need a sturdy root system to thrive. It also works with well for plants like strawberries, which require a heavy load of water to grow.
- Green butter lettuce
5. Nutrient Film Technique (NFT)
This hydroponic system is popular in Europe. It's compact and self-contained. In many ways, this system is similar to the ebb and flow system, but it differs in that the tray that the plants sit in is on a grade, and water constantly runs from one end to the other using gravity.
Like the ebb and flow system, you need a tray, reservoir, tubing, and pump. There is no growing medium in this system and the roots just grow in the nutrient-rich water.
This system provides a steady flow of nutrients, so your plants don't experience the fluctuation common with other types. It also wastes little water, and no growing medium means less cost and maintenance.
If your pump stops working, plants can dry out and die in a short amount of time. This system doesn't work for plants that need sturdy root systems like carrots or beets. You must keep an eye on salinity because it can build up over time.
Because there is no substrate with this system, quick-growing, light plants tend to do best. Heavy fruiting plants also thrive with the NFT if you make sure to give them plenty of support.
- Edible flowers
Aeroponics systems let you grow plants in the air without any growing substrate. Plants are suspended in the air using an enclosed frame, and roots are constantly misted to keep them moist and to supply them with nutrients. This can be done manually or by an automated system.
Many commercial growers use complex systems to grow numerous plants and there are also plenty of home systems on the market in a wide variety of sizes. You can also create a basic system at home using a bucket, sprinkler heads, a pump, a timer and pots to hold the plants in the air.
This system can be mobile, which means you can move it around to suit your needs. Plants grow quickly because they have unfettered access to oxygen and nutrients. It's also a fairly simple hydroponic system to maintain and takes up little space. Many people use stacked systems that are tall but have a small footprint.
If you lose electricity, your plants will be entirely dependent on you to keep them moist. You also need to have a bit more understanding of the nutrient needs of your plants because there is less room for error with this method. You must regularly clean the chamber where the roots sit to prevent disease. While there are some more affordable options, this system tends to be one of the more expensive ones.
Aeroponic systems are ideal for cloning plants for transplant. Plants that have a complex root structure like carrots and beets don't work well in this method.
- Edible flowers
As you can see, there's a hydroponic system out there for almost every plant and person, whether you are looking to grow a good-sized crop for the entire family or a personal supply of herbs and veggies.