Aquaponics vs Vermiponics

This article is geared toward small-scale systems (under 1,000 plants) as our primary audience is the urban farmer/gardener. Some of the points may differ on large scale.

  1. Cost for parts:  
    1. Vermiponics does not require equipment for heating or cooling because operating range for Vermiponics is 45F-90F.  An aquaponic system with Tilapia, for example, has operating temperatures between 70F-90F which often creates a need for climate control and/or greenhouse.
    2. Vermiponics does not require filtration systems.  Solids are not a problem for worms and the microbiome, and plant roots remove excess solids when the plants are harvested.
    3. Vermiponics does not need large stock tanks for fish. Stock tanks are very expensive.
    4. Most Vermiponic systems do not require source water filtration because:
      1. Nutrient levels are 4x that of aquaponic system, which means the small amount of minerals that exist in your water source become insignificant. For example, an aquaponic system may commonly target a Total Dissolved Solids (TDS) level of 300ppm, but the municipal water already has TDS 200ppm. In Vermiponics, your target TDS is often between 700-1000ppm, so the background 200ppm from the water source does not significantly impact your nutrient proportions.
  2. Space:
    1. Fish tanks take up 10-100x more space than vermiculture systems.  Growing space is the same for both systems.
    2. Fish food is grown with conventional agriculture so the complete footprint for aquaponics is quite large.  Vermiponics has no additional land use, as nutrients come from food waste that would otherwise be in a landfill.
  3. Cost of nutrients:
    1. 90%-100% of Vermiponic nutrients come from food waste (or other plant waste) and is therefore free.
    2. If food/plant waste inputs are “anything and everything” as often seen in compost, the vermiponic system will likely need nitrogen and iron supplementation.  It is possible to control food/plant waste inputs so that no supplements are needed. It is also possible to engineer adequate anaerobic regions into the system so that iron is not precipitated out through oxidation and therefore no iron supplementation is needed.   
    3. For aquaponics, organic fish food is expensive and requires land-intensive and water-intensive agriculture to produce the fish food.
    4. Aquaponics still requires iron supplementation and sometimes other supplements too.
    5. Nutrient density of Vermiponic solution is approximately 3 times that of aquaponics.  Vermiponics systems can be run at an optimal EC 1500-2000 us/cm, while aquaponics
  4. Water usage:
    1. Water usage is the same for Vermiponics and aquaponics
    2. Some aquaponic systems require reverse osmosis filtration, which commonly wastes 1 gallons of water for every 1 gallon of clean water that is produced. This means you don’t actually get the 90% water saving that most aquaponic growers claim.
  5. Energy usage:
    1. In Hydroponic systems, higher nutrient density solutions require less flow rate. Aquaponic system require higher flow rates than conventional hydroponics. For example, the flow rate in a NFT channel for aquaponics (EC=500 uS/cm) is 1 L/min whereas with conventional hydroponics(EC+1500uScm) is .2-.4 L/min. Vermiponic solutions run at the same nutrient density as conventional hydropnics and therefore use the same flow rates. This means less energy is used for pumping in Vermiponics, approximately 70% less energy.
  6. Growth Rate:
    1. Because of the higher nutrient density, higher microbial density and diversity, and ability to augment nitrogen levels, growth of vermiponic vegetation is faster.  This is based on observation(we have not yet done a controlled study to give % difference on this) 
  7. Stability, Reliability, Robustness:
    1. Worms are far more robust than fish.  It’s easy for fish to die from disease or system malfunction (loss of temperature control, oxygen, circulation, nutrient toxicity).  The only way your worm population will die is if the vermiculture system gets below 35F or gets above 100F, which is very unlikely to happen.
    2. Worms can thrive in environments with significantly higher nutrient levels, most importantly Ammonia/Ammonium levels. This means that, by nitrification, we can drive the pH lower in Vermiponics. To largely generalize, plants prefer a 6.0pH and fish prefer 7.5pH. So aquaponic systems are usually targeted at 6.5pH, but the healthy range for BOTH the fish and plants is small, 6.4-7.0pH. This requires that the carbonate level be maintained quite precisely at 54-72ppm for aquaponics. In Vermiponics the pH can be anywhere from 5.5-7.0pH because we don’t have to worry about fish. This means carbonate levels can be between 18-72ppm. In Vermiponics the nutrient solution is 100% geared toward the plants, which means you can maintain a perfect solution at 6.0pH and carbonates of 36ppm, but you still have a large error margin where you don’t have to worry about killing either the plant or fish (and once you kill the plants or fish in aquaponics the other will soon die too).
    3. Fish can only withstand Ammonia/Ammonium levels of .5ppm and even that is not a healthy level for them.  This limits the nitrogen levels in the aquatic solution, which limits the growth rate of plants. Worms can withstand  Ammonia/Ammonium levels of 8ppm and greater. This allows for higher nutrient levels without risk of killing the bioreactors (worms or fish).
    4. There is more microbial diversity in a Vermiponic system and this creates greater ecological stability.  The food waste is not homogenous and dead like fish food. Each unique item in the food waste is alive with it’s own microbial community which creates biodiversity for the Vermiponic system.  Microbial diversity creates resilience against disease and harmful microbes, as there are more varieties of beneficial microbes to outcompete any harmful microbes.
    5. Generally, the sensitivity of fish makes the whole system more fragile and prone to crashing or disruption.  A few fish death can cause the whole ecosystem to destabilize and lead to more fish death and more plant deaths.