Both of these soilless growing techniques offer plenty of advantages over traditional soil based growing methods. These include:
- Faster plant growth (up to 2 times quicker than in soil)
- No weeding or backbreaking digging
- No forgetting to water your plants
- You can do it anywhere making it great for urban food production
- Higher plant densities because roots don’t spread out as in soil (can even be done vertically)
The difference of course is that aquaponics uses fish waste as the plant fertilizer whereas hydroponics uses man made nutrient solutions. Aquaponics is also more complex since it involves more than just plants. It’s an ecosystem that includes at least two more creatures: fish and microbes. So keep this in mind when you’re deciding which method to use. You are essentially trading in simplicity for a more natural and probiotic ecosystem when you choose aquaponics over hydroponics.
- Simpler system: Hydroponic systems generally only consist of a tank for the nutrient solution and plant grow area. Aquaponic systems can have fish tanks, sump tanks, biofilters (a place for the bacteria to live), and mechanical filters (to deal with solids accumulation) over and above the hydroponic subsystem.
- Generally simpler to operate: Since there are no fish and bacteria to worry about you can optimize things like pH levels and temperatures for the plants you are growing. In an aquaponic system, parameters such as pH levels and temperatures must be kept in a range that keeps all three creatures happy. Pest control is also simpler with hydroponics because you don’t have to worry about affecting your fish with whatever you’re spraying your plants.
- Less Mess: Aquaponics can also be messier to operate. Ask yourself if you’re OK dealing with fish solid waste and fish harvesting before you choose aquaponics.
- Quicker startup: With aquaponics you have to cycle your system for at least a month to get the microbe communities established and your system will not reach peak performance for another five months. With hydroponics you’re essentially up and running as soon as your seedlings are big enough to transplant in.
- Lower Starting Cost: Hydroponics is also less capital intensive at the start since the systems are simpler.
- Seasonal Growing: Aquaponics does not lend itself to shutting down for the winter and starting up again in the spring since it takes six months just to hit it’s stride. So if you’re in a colder climate, aquaponics should be done in a greenhouse or indoors so that you can run it all year round. With hydroponics, you can easily shut your system down for the winter.
- Probiotic environment: The presence of good microbes makes it much harder for the bad kind to establish themselves. For example, a key battle in hydroponics is root rot and pythium. This is usually not a problem aquaponics. In hydroponics, you are always trying to maintain a sterile system to keep bad microbes out, whereas in aquaponics, good microbes do the job for you.
- One input for two outputs: Although hydroponics is less expensive at the start, aquaponics has the advantage of reusing waste as an input for another product. So for your one input, you get a protein source on top of the plant harvest.
- Water conservation: Hydroponics may use less water than soil growing, but you still have to dump the solution usually after each harvest due to the build up of salts and bad microbes. In aquaponics, water changes are rarely required and water loss is usually only from evaporation and plant respiration.
- Education and Fun: Aquaponics is also great way to get kids interested in healthy eating. It’s much more fun and educational and it’s a great teaching tool for biology, chemistry, and physics.
- Healthier Plants that Taste Better: Aquaponics has also been shown to outperform hydroponics once the system has reached maturity (usually takes 6 months). Plants can grow more quickly, more healthily and often taste better in a well-balanced optimized aquaponic system. This is offset however by the fact that it’s easier to get a hydroponic system up to it’s peak potential.
These lists are not meant to be comprehensive but are a starting point to help the hobby grower make some decisions. On the commercial level there are many other considerations not listed here starting of course with the market you are going after as well as the risks and costs involved with each method.