In a new aquaponics setup, the critical initial wait period is for the cycling process to complete. If fish and plants are added before cycling, you’re going to have issues. As a very rough review, there are three basic elements to the symbiotic relationship in your aquaponics system. The fish eat and produce waste, then several types of bacteria convert that waste to nutrients, and finally the plants consume the nutrients and clean the water for the fish. Invisible to you and me is that second element - the bacteria. Without that intermediate step, ammonia levels increase and cannot be converted to nutrients, so the fish die and the plants starve. The point of waiting in the initial setup period is to allow enough time for a substantial bacterial colony to become established in your biofilter and system.
There are several options when it comes to managing your initial system cycle. Many pond and aquarium owners will actually add a dose of beneficial bacteria purchased from their local aquarium supply store. This is a very quick way to get the bacteria started, but it may not be permitted if you’re trying to establish a certified organic system - it’s worth taking a look. The bacteria you need are actually present pretty much everywhere, so colonies can establish entirely on their own, although it could potentially take months. It’s important to remember that even bacteria need food, so in order to encourage your colony to grow, there needs to be some waste to feed on. Fish make an excellent candidate, and you don’t even need to add your money makers - a handful of goldfish will produce plenty of waste to get you started. Once bacteria are processing the waste, you need a few plants to take up the nutrients so the system doesn’t get overloaded. Once again, a few lettuce plants will do nicely. In a full-scale aquaponics system, this should be enough to get your bacteria well established and ready for the big load, probably in about 4 weeks. It’s very important, once you start increasing the fish and plant load, to monitor your water quality. Ammonia is part of the waste and should remain as close to zero as possible. If it starts rising, it means your bacteria colony is being overwhelmed. If your ammonia is low but ammonium or nitrites are rising, only part of your bacterial team is working. If your nitrates (the nutrients for the plants) are really high, you need more plants to balance out the fish. It can be a complex balancing act to start with, but once your system is in equilibrium, it will tend to stay there.
