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What Are The Best Plants For Aquaponics?
An aquaponics system can be used to grow nearly any type of plant; vegetables, fruits, herbs, and even flowering plants. However, the question that might come to mind is: What are the best plants to grow in aquaponics?
What is Aquaponics?
Aquaponics is the combination of aquaculture (raising fish) and hydroponics (the soil-less growing of plants) where fish and plants grow together in one integrated system. The fish waste provides an organic food source for the plants and the plants naturally filter the water for the fish.
Besides the fish and the plants, the microbes (nitrifying bacteria) is a third participant in aquaponics. These bacteria convert the ammonia, from the fish waste, into nitrites. The nitrites are then converted to nitrates, which are a form of nitrogen that the plants use to grow. Solid fish waste is turned into vermicompost and later becomes a source of nutrition for the plants. The fish waste, serves as a natural fertilizer for the plants to grow and in return, the plants purify the water for the fish.
Selecting Your Plants
The main thing to consider in choosing which plants to grow in your aquaponics system is to first consider the needs of your plants. As a rule of thumb, the more similar your plant’s needs are to the needs of the fish in your system, the better they will grow. It is important that the fish and plants that you select for your aquaponics system have similar needs as far as temperature and pH levels are concerned. The closer they match, the more success you will have. (1)
Making the right choice in aquaponics plants is essential to the success of the system and the success of your harvest. Unhealthy plants effect the purity of the water that can be detrimental to the fish.
Almost all plants can be grown in an aquaponics system, however, some plants have low nutrient needs and grow well in a newly built aquaponic system making them the best “starter” plants for a newly built aquaponics system.
Best Plants to Grow in a New Aquaponics System
It is best to start a new aquaponic system with fast-growing robust plants with low nutrient demand. Some examples are leafy green vegetables, like what you would put in a salad. These will usually grow well in a newly built aquaponics system, making them the “best” plants to grow in a new aquaponics system.
The easiest and one of the most productive leafy greens in an aquaponics system is lettuce. This is because leafy lettuce thrives in water which has a temperature of between 70 and 74 76 °F making it great to pair with tilapia. Lettuce has very little nutritional requirements and can thrive in many environments making it a great confidence building plant to grow in a new aquaponics system. (4)
Watercress is one of the best plants for aquaponics because it is a hardy vegetable and grows quickly. Watercress is easier to maintain than other plants due to its low nutritional demand and can exist alongside many different types of fish. (5)
The cucumber is a water-based plant and an aquaponics system gives them everything they need to flourish. Cucumbers grow best in water with a pH between 5.5 and 7 and grow best in media-based aquaponics systems. (6)
Kale is not a very nutritiously demanding plant to grow but it is a very nutritious plant. Kale can match and exist alongside many types of fish that you may have in your system. Kale is not attractive to pests making it one of the best plants to grow in aquaponics. (7)
Being easy to grow, swiss chard is a great plant to grow in your aquaponics system. Swiss chard is frost resistant making it an ideal plant during the winter season. The nutrients required to grow swiss chard are moderate, using mostly nitrates for leaf growth. Swiss chard grows best in waters with a pH level between 6.6 to 7.0, which is ideal for both the plant and many fish. (8)
Best Plants to Grow in an Established Aquaponics System
Different plants have different nutritional needs, and your aquaponic system needs to be better established to support plants with higher nutrient demands. A well-established system contains all the beneficial bacteria necessary. A well-established aquaponics system is a system that has been running for at from 6 months and up to 3 years for an aquaponics system to become fully established.
These are the plants that grow well in an aquaponics system but requires higher nutrient needs. These are also the best plants to grow in established aquaponic systems.
Tomato plants do exceptionally well in aquaponics systems. Tomatoes like warm weather but also need plenty of nutrient-rich water. Tomatoes are a great option for an aquaponics system where the environment can be controlled. (9).
Cauliflower plants need very little maintenance, they are also resistant to most bugs and diseases. Cauliflower is a water-based plant that thrives in aquaponics systems.
Cabbage needs very little maintenance which makes it one of the best plants in an aquaponics system. They thrive in water with a pH level between 6.2 and 6.6. (11)
Peppers can be difficult to grow in traditional gardening, but it is one of the best plants to grow in your aquaponics system. Peppers are very particular about the water that they consume and they require plenty of sunshine. Growing peppers using aquaponics allows you to monitor and control your nutrients in the water and lets you create the perfect environment for your pepper plants. (12)
Strawberries need very little space to grow and are easy to cultivate in an aquaponics system. Strawberries are one of the best plants to grow in aquaponics because of the constant supply of nutrient-rich water and the ability to monitor and control the system environment. Another benefit is that you can grow them all year round in an indoor system. (13)
What Else Can You Grow in Your Aquaponics System?
Crops or vegetables are not the only plants that you can grow in aquaponics, in fact, flowers are actually a good choice as they are safe from weeds and most pests in an aquaponics system. Here are some great flowers to grow using aquaponics.
Aside from giving a wonderful burst of yellow color to your aquaponics garden, Marigolds have a very strong odor that confuses and drive pests away from your plants. (15)
Many people consider the water hyacinth to be invasive, however, the water hyacinth is excellent in cleaning and purifying the water for your fish which makes it perfect for fish that are sensitive to water changes. (16)
Common Plant Deficiencies in Aquaponics
To ensure that your plants are healthy, you need to avoid plant nutrient deficiency in your aquaponics system and to do this it is important that you recognize this problem and identify the nutrients that your plant needs.
3. Potassium Deficiency
Potassium is needed for plant growth, root development, and seed and fruit growth. Fish feed is often the source of potassium in an aquaponics system but potassium levels in most fish feed are not enough for the plants to grow and can cause potassium deficiency in aquaponics plants. Potassium deficiency in aquaponics needs to be treated because lack of potassium effects plants photosynthesis, which can affects plant growth or plant death.
Sign of Potassium Deficiency in Plants
- Interveinal chlorosis ( yellowing of the space between the plant veins)
- Curling of the leaf tips
- Browning or burnt look on the tip of the leaves
You can supplement potassium by:
- Spraying potassium chloride on the plant leaves
- Adding potassium hydroxide, kelp meal concentrate, or potassium sulfate to your system.
2. Iron Deficiency
Iron is used to produce chlorophyll and other enzyme production functions in plants. Plants cannot produce enough chlorophyll that can retard plant growth if the iron is deficient.
Sign of Iron Deficiency in Plants
- Whitish coloring of the plant leaves
- Yellowing of the leaves between the green veins
- Weblike or spider pattern on the leaves
You can supplement iron by:
- Adding chelated iron to your system.
3. Calcium Deficiency
Calcium is one of the most important nutrients in plants and it is used in the production of flowers, fruits and vegetables. Calcium helps maintain plants strength.
Sign of calcium deficiency in plants:
- Death or withering of young leaves, fruits or flowers.
- Deformed growth of new leaves or fruits
- Blossom end rot
You can supplement calcium by:
- Using hydrated of agricultural lime which will also supplement calcium and magnesium and raising of the pH level.
- Using chelated calcium and calcium carbonate.
Cycling Your Aquaponics System
It is important to cycle your new aquaponics system prior to placing plants in your system. System cycling is the process of establishing your beneficial bacteria within the system so that the bacteria can convert the fish waste (ammonia) into food for your plants (nitrates). Bacteria are essential aspects of aquaponics, serving as the bridge that connects fish waste to nutrition for your plants. (2)
Cycling is a slow process that requires patience, the process involves constantly introducing an ammonia source into the aquaponics unit, feeding the new bacterial colony, and creating a biofilter. The progress is measured by monitoring the nitrogen levels using a nitrate test kit. You will know that your bacteria is established and your system is fully cycled when your test results show an increase in first nitrites then nitrates. Your aquaponics system is ready for Fish after the ammonia level is less than 1 mg and nitrite at 0 mg.
In good conditions, cycling can take about 25 to 40 days. If the water temperature is cool, complete cycling may take up to two months to finish. However, if another aquaponics system is available, it is extremely helpful to share part of the existing system biofilter as a seed of bacteria for the new system.
So What Are the Best Plants to Grow in Your Aquaponics System?
Aquaponics is a great alternative to traditional farming methods and can improve food security. All of these plants will work well with your Aquaponic system. These are, however, only a partial list of what you can plant and that doesn’t mean you can’t try growing other plants! After all, the best thing you can do is have fun experimenting and learning what plants will grow best for you and your situation.