Aquaponics is a sustainable and eco-friendly farming technique that combines the art of hydroponics (soil-less crop farming) and aquaculture (fish farming). Fundamentally, aquaponics is the cultivation of crops in water containing fish. In an aquaponics system, the waste from the fish present in the water provides the minerals required by the plants.
Here are the steps to prepare plants for aquaponic growing:
- Choose the right plant.
- Start seeds.
- Transplant seedlings.
As with any type of agriculture, aquaponics requires some knowledge to make the system work and thrive. Although preparing plants for aquaponics growing can seem like a difficult job, the process is straightforward, provided you pick the right plant and go through the proper steps. The rest of this article discusses the steps to prepare plants for aquaponic growing and tips for planting aquaponics crops.
1. Choose the Right Plant
In truth, almost any kind of plant may be grown in an aquaponic system, including herbs, vegetables, leafy greens, fruiting plants, microgreens, and flowers. You can set up your aquaponic system to accommodate an astonishing array of plants.
Just keep in mind that plants like potatoes, carrots, corn, large onions, large root vegetables, and azaleas are among the plants that grow poorly in aquaponics systems.
Tomatoes, peppers, cucumbers, eggplants, and lettuce are the best plants to grow in aquaponics. Leafy greens like spinach and kale, herbs like mint and basil, microgreens like alfalfa and clover, and fruiting plants like strawberries and bananas are excellent plants to grow using aquaponics.
The decision of which plants to cultivate can be a slight hassle. And while most plants thrive in aquaponics, there are a few that excel. Usually, the ideal plants to grow will depend on what plant you want and the size of your aquaponics system.
Tomatoes
Since they’re fast-growing, generate large harvests, and have a high commercial value, tomatoes are the most popular aquaponics produce. They demand a lot of nutrients and space and, as a result, require more extensive aquaponics systems to thrive. Many tomatoes can be grown using aquaponics, including beefsteak, cherry, plum, and heirloom tomatoes.
Tomatoes grown in aquaponics systems require water temperatures of about 70-80 °F (21.11-26.67 °C) and will be ready for harvest in 4 to 8 weeks. To grow well, they also need 8 to 10 hours of light every day and a pH level of 6.0 to 6.5.
Lettuce
Leafy green crops, like lettuce, have modest nutritional requirements and are suitable for any size of aquaponics farming system. They’re a fitting choice for novices since they thrive in small aquaponics systems. Some of the most common lettuce varieties for aquaponics include loose-leaf lettuce, butterhead lettuce, and Romaine lettuce.
Lettuce grows remarkably quickly from seed to harvest (approximately 6 to 8 weeks) and may even be regrown from stumps. Additionally, the plant demands water temperatures ranging from 65-80 °F 18.33-26.67 °C), 10 to 18 hours of sunshine per day, and a pH level of 5.6 to 6.2.
Spinach
Another leafy food, spinach, is one of the most popular greens to produce in an aquaponics system. The typical harvest time for spinach is 3 to 6 weeks, and the plant requires a lot of nutrients to thrive. As a result, spinach, like tomatoes, need larger aquaponics systems to develop.
Spinach needs a pH level of 5.5 to 6.5 and a water temperature of 45-65 °F (7.22-18.33 °C) to grow. The plant requires at least 12 hours of sunlight every day to thrive in aquaponic systems.
Beans
You can grow bush and pole beans using aquaponics, and while pole beans are perfect for maximizing growing space, bush beans quickly produce a significant number of beans. Beans grown using aquaponics systems often sprout in 8 to 15 days and are harvested in approximately 50 to 70 days.
The temperature needed for beans to grow in aquaponics is between 65-80 °F (18.33-26.67 °C), and both pole and bush beans need at least 12 hours of light each day to flourish. The pH level of the system must be kept between 6.0 to 6.5 to enable the beans to grow.
Strawberries
Like many other fruiting plants, strawberries have high nutritional requirements and require larger aquaponics systems to thrive. They grow faster in an aquaponic system than on soil, but they also produce more prominent fruits, are juicier, and have a superior flavor. You can use aquaponics to cultivate various types of strawberries, including Albion strawberries.
Strawberries generally mature in 4 to 8 weeks. Growing strawberries in aquaponics requires a water temperature of 65-80 °F (18.33-26.67 °C) and a pH level of 5.6 to 6.5.
Blueberries
Blueberries are difficult but suitable plants to grow using aquaponics systems. The plant has meager nutritional requirements, but it can take up to 5 years for blueberries to start producing fruit.
Growing blueberries in aquaponics requires a water temperature of 72-74 °F (22.22-23.33 °C) and a pH level of 4.5 to 5.0.
Basil
Basils are one of the most widely planted aquaponic herbs. Growing basil using aquaponics systems is relatively easy, and the plant requires modest amounts of nutrients. It typically takes approximately 3 to 4 weeks for basil to be mature enough to harvest.
Basils grown in aquaponics systems require water temperatures of about 65-85 °F (18.33-29.44 °C). They need 14 to 18 hours of light every day and a pH level of 6.2 to 6.8 to thrive.
Watercress
The watercress is easy to grow and requires relatively low nutrients to develop. The plant can be harvested in 4 to 8 weeks and needs temperatures of 77-96 °F (25-35.56 °C) to thrive.
The watercress requires 4 hours of sunlight per day and a pH level of 6.5 to 6.8 to grow correctly in aquaponics systems.
Green Mustard
Green mustard is a widely grown microgreen with a high economic value. Green mustards can be quickly produced using aquaponics systems, need 14 to 18 hours of sunlight every day, and have low nutritional requirements.
You need to maintain a pH of 5.5 to 6.5 and a temperature of 60-70 °F (15.56-21.11 °C) to allow the plant to thrive.
Alfalfa
Alfalfa is typically ready for harvest when grown using aquaponics systems in 3 to 6 weeks. The plant is easy to cultivate, needs 12 to 16 hours of light each day, and has low nutritional requirements. Modest temperatures of between 72-76 °F (22.22-24.44 °C) and a pH of 5.5 to 6.0 are preferred.
Generally, when working with a small system, it’s a great idea to choose plants with low nutrient requirements because your aquaponics farm will have fewer fish and fewer minerals for the plants to use. Herbs and leafy herbs are an excellent choice for small-scale aquaponics systems.
2. Start Seeds
After choosing an appropriate plant, the next step is to start seeds for aquaponics farming.
It might be hard for certain seeds to germinate appropriately in aquaponics farming systems due to the unconventional nature of the system. So you may need to coax the germination of plant seeds using seed starting media.
There are three main ways of starting seeds in aquaponics farming systems:
- Direct sowing
- Starter plugs
- Cuttings and cloning
Seeds grown in aquaponics, like those grown in regular farming, require water, oxygen, and the right temperature to thrive. Water and oxygen are absorbed through the seed coat when exposed to the right conditions. Afterward, the seed will germinate and mature into a plant.
Direct Sowing
Direct sowing involves directly planting plant seeds in your bed. This method is best used in a media-based system, where the seed development can be supported by the media, such as rocks or sand. Direct sowing is particularly favorable for leafy greens like lettuce, pak choi, arugula, spinach, and kale.
To use direct sowing, spread the seeds equally on the growth media, pressing them down into the top dry layer, and let them sprout naturally.
Because some seeds germinate better than others in these conditions, it’s good to spread many seeds with the expectation that some will fail. The primary benefit of direct sowing is that you don’t have to transplant your plants into a grow bed, which removes the risk of root damage.
Since this method requires intensive sowing, spread seeds will often need to be pruned after they bud, plucking off excess to minimize congestion. Overcrowded plants will be undernourished, and starvation early on can leave a plant weedy and unhealthy for the remainder of its life, so be sure to cut excess plants early and give plenty of room.
Starter Plugs
An excellent technique to organize your plants in your grow bed is to start seeds in a different media plug and place it in your grow bed. Starter plugs are great for seeds that are difficult to germinate or require more time and attention.
When the seeds have developed to the preferred size, make a small hole in your grow bed and carefully place the seedling inside. Then, using your grow material, gently seal the plug. Use stakes or cords to support the plant until its roots come out from the plug to keep it from falling over.
While various starter plugs are available, compressed peat and paper towels are most commonly used since they are affordable, clean, and easy to obtain.
Cuttings and Cloning
You can start some plants by inserting cuttings firmly into the growing medium (a process known as cloning). Fast-growing herbs rapidly develop roots from cuttings, making the method an excellent way to get a garden started without waiting for seedlings to sprout.
You can also coax a wide range of plants to grow by soaking the cut ends in rooting chemicals. Rooting chemicals are hormones extracted or produced that cause many plants to sprout new roots and are available at most gardening supply stores.
More sensitive plants may need to be rooted in water or a starting media before they’re transplanted to a grow bed.
Cuttings are a beautiful craft with a lengthy history and a lot of specific information about what best fits certain plants. If you have a cherished plant that you’d want to duplicate, doing some study on how to clone that species may be beneficial.
3. Transplant Seedlings
Plant starts can be purchased from a retailer or grown in your garden, and you can plant seeds directly in the soil. Planting your seeds is an excellent alternative if you have a sunny climate for your system. Once they sprout, favorable conditions will help them develop well before the transplantation process.
Once your seeds have sprouted, make sure to provide them with good soil and plenty of light to help them grow. When transplanting seedlings from the soil, fill a small pot with water and carefully wash the soil off the roots before inserting the seedling in the media.
Make sure to place the seedling deep enough for its roots to touch the water.
The transplanting process can cause some damage to the roots of plants, and you can use rooting compounds to aid regrowth. You may also need to support transplanted seedlings using stakes until they are mature enough to carry their weight.
Aquaponic Growing Methods
An aquaponic system relies on the natural environment produced in the farming tank to work properly. Water is only provided to replenish fluid loss due to plant uptake, evaporation into the air, or waste extraction from the system. This agricultural system is effective, takes up little space, and does not need a lot of water.
The methods for growing in aquaponics are:
- Nutrient film technique (NFT)
- Deep water culture (DWC)
- Media-based aquaponics
There are no weeds because the plants are cultivated in water; therefore, herbicides aren’t required. Compared to traditional crop cultivation methods, you may produce a significant volume of food crops with fewer resources. Depending on the technique used, the filtration and plumbing systems, kind of bed, volume of water, and rate of water circulation and oxygenation differ.
Nutrient Film Technique (NFT)
In the nutrient film technique (NFT), plants are cultivated in long canals made from PVC pipes. The plant’s roots hang from the holes and into canals, absorbing nutrients from the water. A thin layer of water flows down the canal at all times, delivering nutrients and oxygen.
Leafy greens, and other plants with a small root mass that don’t require support to develop, can thrive in this system. Larger fruiting plants might be too heavy for the canal, clogging it with their roots. The nutrient film technique is ideal for small spaces and may be installed vertically or horizontally.
The canal used in NFT is usually made with PVC because of the material’s durability.
Deep Water Culture (DWC)
The deep water culture method, commonly known as the raft or float method, involves suspending plant roots in nutrient-rich, aerated water using floating rafts with holes.
This technique is frequently employed in large-scale systems with a vast agricultural area and abundant fish supplies. Plants are cultivated in a medium like rock wool before being transferred into containers that fit into holes made onto a floating polystyrene raft.
The rafts used in deep water culture are usually made of polystyrene. The polystyrene insulates the water and blocks light, reducing the formation of algae. An air pump aerates the water to ensure that it’s adequately oxygenated for the roots of plants to digest the nutrients.
The deep water culture system is the most stable aquaponic farming system since it contains more water, which reduces the risk of water shortages. A raft may sustain plants with a more significant root zone than the nutrient film technique (NFT). Other advantages include the ease with which you may remove plants and the reusability of the rafts.
Commercial companies commonly use this method because of the huge grow beds and extra filtering. On the other hand, the technology is simple to scale and perfect for extensive, high-yield operations.
Media-Based Aquaponics
Plants are cultivated in containers filled with a growth medium that supports their roots in media-based aquaponics systems. Water is pumped from the fish tank, flooding the grow beds and regularly providing nutrients to the plants. The plant bed breaks down all of the waste from the fish tank, and the filtered water returns to the fish tank.
The medium supports the plants and serves as a biological and mechanical filter for capturing and breaking down fish waste. Plants with substantial roots, such as vegetables, fruits, flowering plants, and root vegetables, can be grown in this system. The plants are frequently positioned above the fish tank vertically to save space.
The media bed approach is the ideal option for novices and backyard gardeners. It’s cheap, easy to build, doesn’t require any further filtering, and is quite efficient on small scales.
Tips for Planting in Aquaponics
Here are some suggestions for planting in aquaponics:
Choose the Right Location
Always be sure to choose a suitable location to set up your aquaponics farm. The farm can be situated indoors or outdoors.
Ensure Adequate Oxygen
You should also make sure there’s an adequate supply of oxygen to the system. Proper aeration means that you should employ water and air pumps to ensure high amounts of dissolved oxygen in the water.
Choose Compatible Fish
Make sure you pick the kind of fish that suits your plant. In addition to choosing a suitable plant, you must take care to select a type of fish that complements the plant being cultivated.
Check for Water Circulation & Quality
Ensure there’s proper water circulation, as water circulation is as crucial as aeration in aquaponics systems.
You should also monitor water quality as often as possible. The essential systems to measure in your farm include dissolved oxygen, temperature, pH, and total nitrogen. You must maintain them at specific levels to ensure that cultivated plants thrive in the system.
Pick an Appropriate Tank (& Don’t Overcrowd It)
Be sure to pick an appropriate tank that fits your farming system. Any type of fish tank will work, but flat-bottomed spherical tanks made with fiberglass are a good fit because they’re easy to maintain.
Take care not to overcrowd the tanks, either. Keeping the stocking density modest will make your aquaponic farm easier to maintain. Keep in mind that higher stocking densities can generate more food in the same area, but they’ll necessitate much more active management.
Clean the System as Often as Possible
Uneaten food and organic wastes are highly toxic to aquatic species because they can decay inside the system. Food that has rotted can spread disease and deplete dissolved oxygen.
Space Plants Appropriately
Spacing is essential to discourage competition among plants in your system. Ensure to practice proper and regular prunings to optimize the space in your aquaponic system.
Maintain Balance in the System
Keep a good balance between all life in your aquaponics farm. A batch cropping technique can assist in maintaining a continuous yield of fish and vegetables. This constant yield will encourage stable production and a steady balance between all life in the system.
How Long Do You Need to Wait Before Planting in Aquaponics?
Since aquaponics combines two seemingly unrelated farming systems, it’s common to question the planting process or fish farming methods. The most commonly asked question about planting aquaponics is how much time is needed before cultivating crops.
You don’t need to wait before planting in aquaponics. As cycling would have begun, you can add plants to the aquaponics system as soon as you add fish to the system. Cycling is vital in aquaponics systems because plants require nitrates from the farmed fish to survive.
You can use organic supplements such as liquid seaweed and kelp supplement if your aquaponics system isn’t cycling correctly or if there aren’t enough nitrates in the system. This supplement will aid in stimulating plant growth, forming healthy roots, and increasing the stress resistance of your plant.
Conclusion
Aquaponics is a farming method that combines hydroponics and aquaculture. To prepare plants for aquaponic growing, choose a suitable plant, then start the seed for growing using a proper starting technique. Afterward, transplant the seedlings into the aquaponic system.
There are three methods used to grow plants in aquaponics: nutrient film technique (NFT), deep water culture (DWC), and media-based aquaponics. Although the three methods vary slightly, each system has its optimal use case in aquaponic farming. Additionally, you can start planting in aquaponic farms as soon as you add fish to the system.
