Aquaponic systems are ingenious means of cultivating some of our most basic nutrient requirements. They integrate concepts from both hydroponics, which involves the soil-less cultivation of plants in water, and aquaculture, which is the controlled production of aquatic life. In recent years, aquaponics has increased in popularity due to its potential for being a sustainable means of food production. In the simplest sense, it recycles one of the most vital resources on earth – fresh water.
The thought of establishing a functional aquaponics system can be daunting at first, but just about anyone can produce their own food with the right frame of mind and some basic materials. The good news is the system can be developed at all scales – with a setup that fits right onto your kitchen shelf or one that requires hangar-sized facilities.
Done from the comfort of your home, small-scale aquaponics can be incredibly educational and fun. It may not necessarily feed an entire family, but it should produce a few fresh ingredients for healthy dishes. With the right selection of plants, you’ll be harvesting greens before you know it! Ideal options are those that don’t require much space to continuously produce nutritious foliage. Plants that have similar water, temperature, light, and pH requirements should do well next to one another.
1) Kale (Brassica oleracea)
Also known as leaf cabbage, kale is cultivated all across the globe due to its highly nutritious, edible leaves. Early civilizations established many varieties that were eventually brought far and wide. These were lauded for their culinary uses, minimal growth requirements, and ease of care. As an ornamental plant, kale is quite attractive due to its ruffle-edged leaves and dramatic hues.
In their raw form, kale leaves are predominantly composed of water (84%). They also contain a fair amount of carbohydrates and proteins. As a source of many vitamins, the leaves are extremely rich, with small servings having multiple times the recommended daily values. They also contain minerals, though concentrations of these may vary depending on the substrate type or water source.
As it can tolerate a wide range of pH and temperatures, kale is remarkably easy to cultivate in an aquaponic system. It should be grown in fresh water with a pH range of 6 – 7.5, a temperature range of 55 – 70˚F (13 – 21˚C), and partial shade exposure. Pay attention to the appearance of leaves, which can indicate nutrient deficiencies by becoming yellow, rigid, or spotty. Essential nutrients (N, P, K, Ca, Mg, S) are needed for normal growth.
2) Alfalfa (Medicago sativa)
Alfalfa is a well-loved microgreen that can be added as a garnish to pretty much any type of dish. Its delicate sprouts can also be consumed in larger amounts, as part of a nutritious salad or hot soup. The lightly crunchy shoots and leaves add delectable color and flavor to a wide assortment of dishes. A mere handful can substitute the lettuce component of a leafy sandwich and increase its fiber contents.
The sprouts of this nutritious superfood can be grown all year round and be harvested after just 1 – 2 weeks of cultivation. They can be cut back as soon as they get too crowded or whenever the desired length is reached. Ideally, this tiny crop should be grown on a flat surface that allows its roots to access just enough water. The use of a floating bed can increase the chances of successful and vigorous growth.
Alfalfa should be grown next to plants that don’t require direct sunlight or are sensitive to scorching rays. It may be situated in an area with filtered or indirect sun, if not exposed to grow lights. For year-round growth, the water temperature should be maintained at approximately 70 – 75˚F (21 – 24˚C). The pH should be tested regularly and kept neutral (6.5 – 7.5). When purchasing seeds for use in your system, make sure they are packed by a reputable supplier. For peace of mind, you can sanitize the seeds before you use them.
3) Lettuce (Lactuca sativa)
Perhaps the most popular of all leafy vegetables, lettuce is a fantastic crop for aquaponic cultivation. Individual plants can be situated fairly close together, which makes them ideal for compact setups. The leaves can be harvested after just a month of growth, though the more bulbous or heady types may take longer to cultivate. Go for the romaine, loose-leaf, or butterhead varieties as these can be harvested sooner.
What’s fresher than a summer salad with lettuce leaves collected from your own home? If your sandwich needs more crunch, you can even add some of the outermost lettuce leaves, allowing the smaller ones to grow larger before the succeeding harvest. That the leaves don’t come into contact with dirt is a huge plus and can drastically help reduce cleaning time and the risk of soil-borne diseases.
Though lettuce is mostly composed of water, it is rich in vitamins K and A. Its leaves also contain decent amounts of iron and folate. As it has a considerable nutrient demand for proper growth, it would be prudent to regularly check the nutrient levels in your aquaponic system. Water temperature should be maintained at around 70 – 74˚F (21 – 23˚C). This temperature range should also be optimal for many types of fish.
4) Basil (Ocimum basilicum)
Basil is a fantastic plant to grow in a small aquaponics setup placed right by your kitchen window. Whenever your Mediterranean dishes need a little more flavor or color, you can snip a few leaves without harming the growth of the plant. Varieties that are popularly grown in aquaponic systems, due to their value in the culinary industry, include sweet basil, Thai basil, holy basil, and lemon basil.
Apart from the flavors a few basil leaves can impart to food, they also provide antioxidants, calcium, and vitamin K. As if those benefits aren’t enough, sweet basil leaves can supposedly aid in lowering blood sugar too! It’s no mystery why this edible herb is a favorite and an absolute must-have in every home. As just a small amount is needed to bring intense flavor, a single plant can be sustainably harvested so that it lasts for quite some time.
Basil can tolerate slightly acidic water that dips down to a pH level of 5.5. It should be grown in a water temperature range of 68 – 77˚F (20 – 25˚C), though it can easily tolerate slightly lower or higher values as well. Most varieties thrive best in sunny locations but are sensitive to intense light that may burn the delicate leaves. Grow lights can be used as well. Make sure to keep the aquaponic setup away from pest sources, wild animals, and potential thieves that may attempt to snag your valuable plant.
5) Swiss chard (Beta vulgaris subsp. vulgaris)
If you like the texture of kale and the taste of spinach, you’ll love Swiss chard. A notable member of the beet subfamily (Betoideae), this biennial plant is a cool-weather crop that can be grown outdoors in temperate zones. It is able to tolerate mild frosts but does grow best in fully controlled setups.
Swiss chard is perfect for use in small-scale setups that are intended for continuous, partial harvests. The removal of the outermost, large leaves encourages the growth of new ones. Never harvest more than 70% of the plant at one time to ensure repeated yields for as long as possible. This crop is great for those who are new to aquaponics because it can tolerate stressful conditions. Nonetheless, optimal parameters can facilitate quick turnarounds and harvestable sizes in as little as 4 weeks.
Swiss chard is popularly known for its deeply colored leaf stalks. Depending on the variety, these can range in color from red to yellow and white. For best results, grow this species in water temperatures ranging from 55 – 75˚F and a pH level between 6.6 – 7.0. The leaves can take full sun exposure, but if ambient temperatures exceed 26˚C, they should be provided with shade.
6) Watercress (Nasturtium officinale)
A freshwater plant by nature, it’s pretty obvious that watercress would thrive in an aquaponic setup. Its water-loving roots and hollow stems are fully adapted to an aquatic existence. This flowering species is one of the oldest vegetables in cultivation and is now grown and sold all over the world. Its highly nutritious leaves and shoots can be consumed raw or cooked. Though low in dietary fiber and carbohydrates, they are rich in many vitamins.
Watercress can be grown via seed or using plant cuttings. The entire plant can tolerate being partly submerged, although growth on a medium placed on a floating raft should ease maintenance and harvesting. Seeds can simply be sprinkled onto the growth medium. In a few days, they should begin to sprout abundantly. The seedlings can eventually be spaced apart to give more room for the plants to grow.
Ideal growth conditions for watercress include mild temperatures, ranging from 50 – 60˚F (10 – 15.5˚C), and pH levels ranging from 6.0 – 7.5. The aquaponic setup can be situated either outdoors or indoors, as this species can tolerate full sun exposure in agreeable climate conditions. If the setup is indoors, grow lights can be used.
7) Arugula (Eruca vesicaria)
Known for being quite pungent and strong-tasting, arugula is widely cultivated due to its nutritional value. This herb was used for culinary purposes as early as Roman times. It is a popular addition to salads and pizza. Traditionally grown next to other herbs in private gardens, it is now commercially produced in many hydroponic facilities.
Arugula is a fast-growing annual that prefers cold weather. As it can be harvested and is pleasant to eat as seedlings, it can sometimes be grouped together with microgreens. For arugula to thrive in a small-scale aquaponic system, it should be grown in cool water ranging from 45 – 65˚F (7 – 18˚C). It favors neutral pH levels (around 6.0 – 7.0) and partial or filtered sunlight. Interestingly, intense sun in warm climates can cause the leaves to become more bitter.
If you’re growing arugula as microgreens, the seedlings can be harvested as early as 10 days past the initial sprouting period. The harvesting process is incredibly simple! All you need to do is cut the shoots just above the roots. Rich in vitamins C and K, arugula is definitely good for you. Though small, even the microgreens are several times more concentrated in vitamins than iceberg lettuce.
8) Spinach (Spinacia oleracea)
Popeye’s miracle food for strength, this well-loved vegetable is now present in all sorts of supermarket forms – fresh, canned, frozen. There’s nothing quite like the freshest leaves, however, as their nutritional value diminishes after just a few days in storage. The fresh leaves are a rich source of most major vitamins, and they contain moderate amounts of calcium and dietary fiber as well.
When cultivated in an aquaponic setup, spinach will typically reach a harvestable size in 4 – 6 weeks. The entire plant need not be collected at once. If you’re growing spinach for your personal use, harvesting just a few leaves (starting with the largest, outermost ones) every week may increase overall yield. To begin cultivation, you can sow seeds onto a growth medium or make use of seedlings. Seedling roots should be thoroughly cleansed of soil beforehand.
Spinach can be grown in water temperatures ranging from 45 – 75˚F (7 – 24˚C). The leaves can tolerate long periods of full sun exposure, though partial shade may also result in a good yield. If the setup is indoors, dedicated grow lights or fluorescent lighting may suffice. Regularly check the water’s pH, making sure it stays between 6.0 – 7.0.
9) Pak choi (Brassica rapa subsp. chinensis)
Also known as bok choy, pak choi is a staple crop in China and is a common ingredient in many East Asian dishes. It is now grown in several Asian countries and is sold in supermarkets all across the globe due to high demand. If you’re just warming up to the idea of aquaponics, this is a great plant with which to start. This tasty, biennial crop comes in many varieties apart from the two most popular types – a white-stemmed version and a green-stemmed (‘Shanghai’) one.
Pak choi is more likely to thrive in mild climates, where temperatures range from 55 – 75˚F (13 – 24˚C). As it is frost-tolerant, it can easily tolerate water temperatures that are slightly lower than this range. Warmer temperatures can compromise growth and cause bolting. This condition is depicted by the premature production of flowers and seeds.
Highly nutritious and flavorful, this is one vegetable that you’ll definitely find yourself craving time and time again. You can make all sorts of stir-fried dishes using the entire leaves. You can grow a handful of hybrids next to one another to compare the subtle differences in form and taste. Some varieties can be harvested in as little as 3 weeks! To ensure that the leaves are crisp and tender, harvest the largest, lowermost leaves first. With proper care, a single stalk may last for a few months.
10) Chives (Allium schoenoprasum)
If you purchase a bundle of fresh chives from the grocery, try saving a few stalks (with roots) and place them in a container with water. That’s how easy it is to continuously cultivate this plant! An aquaponic setup that has a regular input of nutrients is an absolute dream for chives. In practically no time at all, you’ll find yourself with too many leaves to harvest and not enough dishes to throw them into.
Although chives belong to the onion family, they don’t produce the underground bulbs that their close relatives do. This is partly what allows them to thrive in water instead of soil. Luckily, the lack of a traditional bulb does not prevent them from being rife with valuable nutrients. Just a few spoons of chopped leaves are needed to enhance not only the flavor but also the vitamin content of dishes. Additionally, chives contain choline, a compound that promotes nervous system and cell health.
Chives require around 12 hours of sunlight per day to reach their maximum growth threshold. This perennial herb is able to tolerate cool temperatures but thrives best at a range of 65 – 80˚F (18 – 27˚C). The water pH should be maintained at 6.1 – 6.8 to promote the efficient absorption of nutrients. When harvesting leaves, you can cut down to the base of the plant, leaving just 1 – 2 inches. New leaves should continue to grow as long as the crown remains intact.
