Pets are loyal and wonderful friends to have under any circumstance. The biggest caveat is their stinky feces which are good for nothing… or are they?
As a general rule, fish, bird, cow, pig, and goat droppings can be used in hydroponics. However, they need to be thoroughly processed. Dog and cat droppings are not recommended in hydroponics as can be a dangerous career of disease.
Most hydroponics systems use a sterile reservoir, mixed only with chemical nutrients. However, one can use organic fertilizers like animal droppings to augment their hydroponics systems with naturally occurring nutrients.
Animal droppings have been used to feed the plant essential macro and micronutrients through waste discharge. The most common form of this is aquaponics, the marriage of aquaculture and hydroponics.
In aquaponics, the discharge of the fishes in the water is used as the nutrients for the plants, and this nutrient-rich water is brought to the growing bed. The plants absorb the nutrients in the water which effectively cleans and filters it. It is then recirculated again into the fish tank. In essence, the fish in the water is the nutrient reservoir.
Aquaponics (by extension, fish discharge) is preferred because of how simple and intuitive the system is to implement. Fish also have the added benefit of releasing ammonia from their gills. Ammonia helps plants produce healthy roots.
For the hobbyist, it lets them augment their currently in-use aquarium with their hydroponics system. The same can be said for commercial growers on a much larger scale. For these growers, it helps them augment their earnings by adding fish produce to their sales.
For aquaponics, it has been a tried and tested method used by hobbyist and commercial growers.
However, for other droppings, their use as organic fertilizer for hydroponics is more complicated. Using other animal droppings may prove more of a challenge since they may require a specialized process.
Some droppings are more recommended than others while some cannot be recommended until further studies have been conducted or better methods have been invented.
Pets come in all shapes, sizes, and species. Their droppings reflect that hence not all of them can be recommended to be used as nutrients for hydroponics. Some are more suitable than others while others are completely not recommended.
As said before, fish droppings are the most viable means to organically fertilize hydroponic plants. They provide a near-seamless integration with hydroponics. Since the waste is already in a form easily absorbed by the plants.
Hence, the problem here is not the droppings themselves but the consideration of how many fish there should be in the aquarium. There should be enough fishes to sustain a plant’s essential needs. For small fishes, the general rule of thumb is 1 inch of fish per gallon. For larger fishes (10-12”), it should be 1 large fish per gallon.
Dog droppings are a possible alternative but not recommended since there are some considerations that should be given notice first. The omnivorous diet of the dog will affect the nutrient content of the manure.
Dogs lick many objects, animals, and may carry parasites because of that.
Dog droppings are good for traditional soil gardening when dried and composted but cannot be, in good faith, recommended for any hydroponic application.
Cat droppings are not a viable alternative and not recommended for use in hydroponics. Cats may have gastrointestinal parasitism or a disease known as toxoplasmosis.
Cat droppings are not recommended even in regular soil gardening or composting.
Cats are omnivorous hence the composition of their droppings will vary and remain inconsistent. Up to 45% of cat populations have gastrointestinal parasitism. Furthermore, some cats may be infected with a disease known as Toxoplasmosis. Infection in humans could result in body aches, fever, fatigue, and headaches, among others.
Due to this, it is not recommended to integrate cat droppings as nutrients in a hydroponics system. Pregnant women, and people with immune system problems can be at risk if consumable plants were grown using cat droppings.
Chicken, pigeon, or turkey droppings can be used in hydroponic systems. Studies have shown that these contain a high amount of ammonium and nitrates. It was also discovered that the same had 29%–79% higher concentration of ammonium nitrate and total nitrogen compared to the Hoagland solution.
How is it prepared?
Some growers have these birds and collect the droppings. The air-dry droppings are placed in a bag that has small holes. They are tied close and placed in the reservoir. In essence, it becomes a very stinky “compost tea.”
It is recommended that the droppings be dried first under the sun to kill off harmful bacteria.
What are the results?
There have been documentation of such a method. For example, in 2015, a project in Alberta Canada used poultry manure as fertilizer for their hydroponics. It was stated that the yield of their tomatoes using poultry manure digestate was 15% higher than those using synthetic fertilizer.
Though not traditionally seen as pets, goats, cows, and pigs can serve as loyal additions to any home. Goat and cow are preferred; they are herbivorous and as such their manure is rich in digested organic plant matter. Research on using farm animal manures are also more widely available and thus easier to recommend.
Goat droppings have shown some promise as hydroponic nutrients according to studies. Studies have shown that the incorporation of goat droppings improved plant growth and yield. Hence, goat droppings are a feasible alternative to conventional hydroponic methods.
How is it prepared?
A study conducted by the Sebelas Maret University, Malaysia provided a methodology on how to prepare the mixture. 2kg of air-dried goat manure was mixed thoroughly with 0.5 kg of sugar, 1kg of ZA in 20 liters of water for 5 minutes. The mixed materials were then capped and fermented at room temperature. The fermented mixed materials were then stirred manually for 2 minutes per day for three weeks. Different ratios of liquid fertilizer goat manure (LFGM) with AB-Mix.
What are the results?
The results of the study show that the combination of LFGM with AB-Mix in ratio 1:1-3 resulted in similar plant growth with those applied with commercial synthetic hydroponic nutrients. This concludes that LGFM can be used as fertilizer or an extender.
Cow and pig droppings are viable as hydroponics nutrients. This is because they are easily sourced and a common waste product in farms. Cows digest plant matter thoroughly. Pig droppings contain essential nutrients but require composting to be safe for use due to the presence of E. Coli.
A detailed study was conducted by the Pibulsongkram Rajabhat University, Thailand detailing the method and the results in using these materials.
How is it prepared?
The droppings were air-dried and ground in a chamber. The manure was mixed and fermented in groundwater for 24 hours in ratios of 1:50 The mixture was filtered through a thin white cloth and diluted a solution with groundwater in ratios of 1:3. The diluted solution would now serve as the hydroponic nutrients for the plants.
What are the results?
The results show that cattle and pig droppings showed similar results of effectiveness. They are less effective than chemical fertilizers. As such, their application may be limited. They can be best used if the grower is adamant in creating a chemical-free produce or extenders in conjunction with chemical fertilizers.
Common to all these methods is that the droppings are not used the moment they are excreted. The droppings must often be dried or composted through aerobic or anaerobic composting.
Drying is a simple enough process of leaving the organic matter under the sun so that the sunlight will kill some of the harmful bacteria and evaporate the remaining moisture.
For aerobic composition, it is as simple as digging a ditch and placing the droppings there with other organic materials such as grass clippings. Anaerobic composting can simply be done by placing the manure in a plastic bag and left under the sun. There are other methods available however the abovementioned are often the simplest.
Knowing that poop can be used for something more than flushing down the toilet is good and all however there will be a problem – the smell!
Using them indoors may cause discomfort due to the smell, making the gardening experience less enjoyable. Smells can travel through liquids and can even bind themselves to walls, fixtures, and furniture.
If you are using animal droppings outdoors, then there should be no problem. The smell would not be so concentrated as to cause discomfort and annoyance to the senses. It would have been dissipated by the wind.
Additionally, using animal droppings for hydroponics would require much more cleaning and monitoring to make sure that gunk or other unwanted formations would not disrupt the system. So apart from the smell, cleanliness is a consideration too.
- Animal droppings can be used in hydroponics systems. However, their use is predicated on their preparation and the animal they came from.
- The droppings of cats and dogs are not recommended.
- The droppings of fish, birds, goats, cows, and pigs would serve as good nutrients for plants but may still require the inclusion of chemical nutrients. Hence, animal manure in hydroponics can be used either as a substitute or as an extender to chemical nutrients.
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