With modifications to the standard rafts and pots used in aquaponics and hydroponics, nearly any edible or ornamental plant can be grown in the system. Some of the strangest plants trialed in these systems include dwarf banana and citrus trees, huge rooted taro plants, and sprawling raspberry and blackberry canes. But just because it’s possible to grow a certain plant in aquaponics doesn’t mean it will be a profitable or worthwhile endeavor. For commercial systems that aren’t for research or hobby use, farmers need to stick to proven plants to get a few reliable harvests sold before branching out into trials of the unusual and alluring.

Edible Plants

Edible crops are the most common plants grown in aquaponics systems. It makes sense if you’re already marketing fish as food that you can use the same connections to find restaurants, consumers and wholesalers interested in vegetables and fruits. Edible plants also tend to grow relatively quickly, although that varies whether you choose to grow annual or perennial crops. Many people assume that only annuals will turn a profit in a system like aquaponics, but long-term perennials may be even better if you can afford to wait a few years for them to settle in first.

Annuals

Annual plants are those that accomplish all their growing within one season – or at least one calendar year – and then die off. This includes sprouting from a seed or root and reproducing. The majority of food crops, including everything from melons to grains like wheat, are annuals.

The benefits of annuals in an aquaponics system are:

• A shorter growth period; allowing for multiple harvests in a year of a single type of crop and continuous harvests with staggered planting and by growing a variety of different plants.
• Regular replacement cycles and shorter growth periods; which reduce disease pressure that can build up with long-term perennial plantings.
• Crop rotation; which is possible to reduce disease pressure when media beds are used instead of rafts or nutrient film systems.
• Easier estimations of harvest size for profit forecasting and budgeting; many annuals are harvested by the entire plant, such as lettuce, radishes and more.

Some of the best annuals for profitable production in an aquaponics system include:

Lettuce and salad mixes with arugula, colorful mustards, spinach and similar small and leafy greens. These plants thrive on the nitrogen offered by the fish and require relatively low levels of other nutrients because they don’t need to flower or set fruit by harvest time. You can cut them at baby size and fetch a higher price, resulting in a very short growth period of as little as 20 to 30 days with the right varieties and an optimized system. They’re also some of the most cold-tolerant crops to grow in aquaponics without heated water, but the right varieties still grow well in warmer climates nearly year round.

Watercress. As the name suggests, this plant doesn’t even need rafts or any growing medium to produce copious amounts of peppery flavored leaves. It is happy to float along on the surface of water troughs and reproduces rapidly enough that it can pose a clogging hazard to filters and pipes. Don’t add it to fish tanks because it can’t necessarily handle the raw ammonia produced by their waste. It’s a great filler for gaps between rafts where the water’s surface is exposed, and can be harvested weekly once established with little impact on the overall growth.

Edible herbs like mint, cilantro, basil and parsley. Some varieties are more finicky about water culture than others, but in relatively warm climates, most edible herbs grow well in the aquaponics system. These plants tend to demand a much higher price per pound than other crops, but some areas and markets are already saturated with these products. Don’t overestimate your ability to sell specialty crops with limited demand, even if they fetch a very high price. You may need secondary processing facilities for drying and packaging the herbs to make their culture worthwhile.

Tomatoes, peppers and eggplants. These three members of the nightshade family can all produce in heated aquaponics systems with high stocking rates. They need plenty of nitrogen, potassium and phosphorous to grow large enough to set fruit successfully. You may be able to raise them in outdoor and unheated systems in warm climates that don’t experience freezing temperatures in the winter. Peppers and eggplants are relatively compact compared to tomato plants that can grow six to 18 feet tall in aquaponics greenhouse environments, but they’re all larger plants that take up a lot of space on rafts or nutrient film tubes. Hot peppers and chiles are among some of the best peppers to grow due to high demand and high prices, along with wholesale demand for hot sauce production and canning.

Root crops like radishes and turnips can grow well, but tend to need a raft and growing medium that holds the main root out of the water and only keeps the tip and feeder roots wet to prevent rot. These pots can be tricky to set up and seed for beginners.

Squash and melons enjoy the nutrient balance and wet environment but take up a lot of space for the amount of harvestable product. One sprawling zucchini plant, even from a variety bred to save space, may produce a dozen pounds of harvestable fruit in a season. But if you compare that to the ability to harvest over 100 quick-growing lettuce heads from the same space in the same amount of time, you’ll likely find the smaller plants are more profitable in the long run.

Sweet potatoes are a great option if you can design rafts that keep the growing tubers out of the water to prevent rotting, which is the main reason why Irish potatoes won’t grow properly in aquaponics systems.

Corn tends to be too large for these systems and either tips over and snaps or weighs down rafts until they sink. Finally, grains are simply impractical to grow in these kinds of enclosed systems, as each plant produces so few grains that acres of open land is required for the scale needed to get a decent harvest.

Direct seeding is the most popular method for most aquaponics systems, including rafts, media beds and nutrient film tubes. Seeds can be planted right into the growing medium in most systems, and floating rockwool cubes are available for water culture systems that don’t usually rely on any media. For complete beginners, ordering transplants prepared for hydroponic or aquaponic use is a great idea. The cost of these started plants will likely be high enough to minimize the profit of this first generation, but the experience you’ll gain from starting with healthy and ready-to-grow plants is likely worth the cost. You can practice your seed starting skills while tending the transplanted crops to make sure you’re ready to follow them with a steady succession.

Perennials

Perennial plants keep coming back, year after year. In warm climates, without hard frosts in the winter, perennials planted in the ground tend not to die back and continue growing all year round. In the heated greenhouse environment, this can mean continual harvests if light levels remain high enough to trigger flowering and fruiting. There’s also no need to constantly baby new seedlings and transplants until they start growing vigorously, reducing upfront labor at the beginning of planting cycles. Unfortunately, perennials do have some drawbacks in the aquaponics environment. They tend to be much larger plants, including shrubs, trees and canes. Some, like blackberries and raspberries, sport irritating thorns or spines. Due to their long growth periods, they’re more likely to face a disease or pest at least once. Also, most perennials need years of growth before they produce anything worth harvesting. Despite all these disadvantages, the ability to create a steady harvest of high value fruits and vegetables makes it worth considering at least a few perennials as part of your overall crop system.

Viable perennials for aquaponics include:

Strawberries, which require a moderately cool climate and a lengthy spring-to-summer transition or careful heat control to trigger flowering and fruiting. One challenge to growing strawberries, and most other fruit, in covered aquaponics is the need for pollination. You’ll need to bring in bees or other pollinating tools to get a good crop of strawberries, even in some cases for outdoor and uncovered systems that lack natural pollinators.

Dwarf fruit trees, although they can take five or more years to begin fruiting and require a lot of space. These trees need modified raft or nutrient film systems that are designed to accommodate their extensive root systems without clogging, so they can’t just be mixed into other systems. However, tropical climates and heated greenhouses can produce bananas, papayas, pomegranates, figs and more. It can be used for either fresh sales or dried fruit production.

Rhubarb and asparagus. Both harvested for their stems rather than leaves or fruit, these two perennial plants are easy to purchase in bulk in the form of root cuttings. Within just two to three years, you should be able to start harvesting them without damaging the plants. Both require lower temperatures and tend to only produce in the spring, but some manipulation of the greenhouse environment may allow you to produce multiple harvests a year in cooler climates.

Ornamental Plants

In areas where there is too much competition for fresh produce from traditional agriculture methods, ornamental plants may offer a much better profit margin. The majority of ornamental aquaponics commercial sales are focused on cut flowers, but that’s not the only option for production. It’s also possible to sell nursery stock and even houseplants directly to consumers after culturing them from seed or cuttings in the aquaponics system. This method even works for edible herbs that are sold at direct sales platforms like farmer’s markets, or wholesale to companies, who retail them through grocery stores and plant centers.

Cut flower production is often a challenging way to earn money because most flowers bruise easily and require plenty of chilling and careful handling, not to mention extensive packaging. Yet, if you’re located near a large metropolitan area with plenty of demand for wedding and florist supplies, the extra work of cut flower growing is likely worth the high rates you can charge for higher quality and local plants.

Ornamental aquaponics plants are almost entirely annuals, as roses and other perennials tend to be too large and disease sensitive for this kind of growing. Some popular varieties include:

Houseplants like pothos, cast iron plant, small palms and dwarf elephant ears. These tropical plants all tend to root well in water even with a growing medium, but using net pots is recommended if you plan to sell them in pots. They will experience shock if roots are transferred from a water culture to a soil or soilless growing medium. As long as you can supply plenty of warmth, these plants tend to have lower light requirements and relatively low nutrient needs compared to edible crops or flowering ornamentals.

Edible flowers can be sold as both decorative and delicious products to two different markets. These include violets and violas, many orchids, nasturtiums, calendula, some begonias and carnations. Many of these plants are also in high demand for floral arrangements, creating two distinct streams of income from the same plants.