How to Grow Microgreens in Aquaponics

Fine dining restaurants recently introduced microgreens to add flair to their different array of dishes. Since then, these tiny, delicate greens that add texture and flavor to various food as garnish or ingredients have become popular to vegetable lovers. 

Big on nutrition and flavor, microgreens can be expensive to purchase. But they can be grown cost-effectively at home through aquaponics. A do-it-yourself microgreens aquaponics system is simple to set up, rewarding, and sustainable. In this article, you'll know what microgreens are, the best microgreens to grow in an aquaponics system and how to get started with your own microgreens aquaponics system. 

What are Microgreens?

Also known as "vegetable confetti," microgreens are baby vegetables and herb plants harvested when they are 1-3 inches (2.5-7.5 cm) tall. These tiny greens are packed with flavor and nutritional values. You can use microgreens for salads, sandwiches, or stir-fried recipes.

Microgreens grown in aquaponics systems can be profitable and sustainable. However, like any growing system, it has pros and cons, which are discussed below.

Pros of Growing Microgreens in Aquaponics:

• Quick turnaround time:Microgreens can be ready for harvest in under two weeks from when you sow the seeds. 
• Nutritious:Microgreens have all the nutritional and health benefits of a full-grown plant.
• Efficient use of space:You can grow microgreens even in small aquaponics systems.
• High demand crop: Microgreens are high demand and profitable crops.

Cons of Growing Microgreens in Aquaponics

• Time-consuming:Microgreens needed to be checked daily, replanted every two weeks to get a continuous supply.
• Excess Harvest: Microgreens are best when eaten fresh and not great for storage, making it difficult if you have excess microgreens. 
• Sensitive to changes: Microgreens are easily affected by small changes in temperature, light, and water quality. 

What are the Best Microgreens for Aquaponics?

There is a wide range of vegetables that can be called microgreens. Growing microgreens requires a flat surface that allows the microgreen seedlings to grow a few inches and grow their first leaves. These are some of the common, most profitable microgreens and the best ones to start growing in your aquaponics system.

• Arugula

Arugula is a fast-growing herb. This cool-climate vegetable belongs to the Mustard family that includes plants such as bok choy, cabbage, and watercress. Arugula is rich in nutrients and a staple among fresh salads, casseroles, pizza, and sauces. 

The optimal harvest period for arugula microgreens is around 10 days. A 10-inch x 20-inch media bed can grow 1.5 ounces of seeds per tray. Follow the normal process of growing arugula, but since you are growing microgreens, they can be harvested once they produce small green leaves. You can harvest these herbs by cutting at the stem leaving the roots. 

• Pea Shoots

Pea shoots are crunchy, sweet, and taste like young snow peas. They are popular with chefs because they look great in exotic dishes. Pea seeds need to be soaked for up to 24 hours before sowing them. You can harvest them once they reach around 2 inches in height. Pea microgreens regrow after you cut them, allowing for multiple harvests per tray.

• Mustard

Mustard is excellent to grow if you're looking for spicy-tasting microgreens to add a peppery zest to your salads. Mustards take three to four days to germinate and can be harvested in another six to ten days. 

• Radish

Radishes are perfect for aquaponics beginners who want to get started. Radish microgreens seeds don't need soaking and germinate quickly in one to two days. They are full of healthy vitamins and nutrients and have a spicy flavor and attractive color that sheds love. Radish microgreens are usually ready to harvest in five to ten days.

• Kale

Kale is another microgreen that herb lovers love. You can see the common green leafy kale, but these herbs have ornamental varieties in purple, magenta, and black-green color. Kale seeds don't need soaking; just sow them evenly on your grow bed and cover for three to five days to block them from light. 

• Coriander

Coriander microgreens offer numerous health benefits. Herb lovers enjoy mixing coriander in soups and desserts because of its citrusy and spicy flavor. You can plant coriander seeds in your system and monitor for real green leaves to appear between 14 to 21 days. Once the leaves come out, you have to wait for another week before harvesting to provide more flavor. 

• Basil

Basil microgreens require more heat than other microgreens. They are best grown during the summer months, and they germinate in one to two days and can be harvested in 15 to 20 days. The most common variety of this herb is the sweet basil, but there are other types of basil, like holy, lemon, and Thai basil. 

The Best Aquaponics Method for Growing Microgreens

Due to the small nature of microgreens and the fast growth time, the media basedand raft system are the best aquaponics methods for growing microgreens. The basic principle of growing microgreens in aquaponics is that microgreens require a large flat surface that will allow all seeds to receive light and nutrients equally to grow and attain a few inches of height to be harvested and enjoyed. 

• Growing Microgreens in the Grow Bed

Grow beds are ideal for creating a large and flat surface for growing microgreens. It doesn't matter what media you use. You can sow your microgreen seeds by using a hemp grow mat on top of the grow bed. This will provide a flat surface. The hemp grow mat will be about an inch deep and take up water through the tray to keep your microgreens moist and grow well.

• Growing Microgreens in the Floating Raft

If you have a raft system or deep water culture (dwc), the best way to grow microgreens is to use netting pots lined with hemp grow mats. The netting pots will let the water flow around the roots, while the grow mat will stop the seeds from being flooded. The bottom of the net pots should touch the water to ensure they are constantly moist. 

The Best Fish for Growing Microgreens in Aquaponics

Microgreens like warm temperatures, and the good news is that they can be grown with any fish that likes warmer water. The best aquaponicsfish like tilapia and goldfish are good starting fish because they are hardy and can tolerate water quality changes. However, other fish species like perch, largemouth bass, and koi can also be used to grow microgreens. If you intend to use tilapia, refer to our blog, how to raise tilapia in aquaponics. 

Considerations for Growing Microgreens in Aquaponics

• Dampen the growing tray or hemp mat, remove the excess water so it is soaked but not soggy.
• Mist the seeds equally. Larger seeds are more demanding and challenging to grow, so make sure the whole seed stays moist. 
• Use shallow trays of at least 2 inches deep. You can use burlap, hemp mats, or paper towels and place them on the trays to plant your seeds. Cover the trays with mats or paper towels after sowing until the seeds germinate.
• The ideal temperature for growing microgreen is around 70 ° F (68 - 72).
• Avoid direct light until germination takes place. If you're using LED lights, prefer the moderate intensity of around 30W. Place lights about 30 cm above the tray and provide lights for 12 to 14 hours per day, especially for indoor aquaponics systems. 
• Maintain moisture on the tray until harvest.
• Purchase seeds particularly listed as microgreens. 
• Provide sufficient circulation to prevent pests and diseases.

How to Set up Microgreens in Your Aquaponics System

If you don't have your aquaponics system yet, you have the option of purchasing a ready-made system, or you can DIY your own aquaponics system. If you choose to DIY, you can refer to our ultimate aquaponics beginner's guide. Use the guide below to set up your microgreens aquaponics and enjoy a continuous supply of nutritious microgreens and other vegetables. 

1. Prepare the Water

Microgreens are sensitive to pH, so once your system is reading for planting, the first thing you need to do is to check and prepare your water. The ideal pH range for growing microgreens is 5.5 to 6.5, but microgreens grow best at the pH of 6. Make sure your water is within the ideal pH range for microgreens.

2. Soak the Grow Mat

Cut the grow mat to your desired size or to fit in the growing trays. Then wet the grow mat and lay it on top of your media bed, floating raft, or growing trays. When you flood the media bed, the grow media will hold the water and capture nutrients that are absorbed by the grow mat for the microgreens.

3. Add the Seeds

Sprinkle the microgreen seeds evenly into the entire grow mat but avoid overcrowding. Each type of microgreen seed requires a different seed density, so always refer to the seed packet or research the optimal seed density of your crop. Some seeds need to be pre-soaked while others don't, so again, refer to the growing instructions of your microgreen seeds. You can sprinkle two to three tablespoons of smaller seeds like arugula directly into the growing mat. 

4. Cover the Seeds

It is good to cover the seeds for the first few days to prevent the light from getting in during the early germination stage. You can uncover it after 4 or 5 days. You can check your microgreens by watching for when the baby leaves (cotyledons) first appear. Once your crop is uncovered, ensure it gets an ample amount of light.

5. Harvesting

Microgreens will wilt very fast after harvest. So if the climate is too hot, move your microgreens into a shady, cool place for harvesting. It is also recommended to harvest microgreens during the late evening or early morning, where it is cooler. This way, the harvested microgreens will stay fresh and crisp. Most microgreens will be ready for harvest in 10 to 21 days, depending on your crops.

6. System Maintenance

Maintaining a microgreens aquaponics system is just like any other crop aquaponics system. You will need to check them regularly, feed the fish, and ensure that the system's water quality is maintained at all times. However, microgreens grow faster than other crops, so you will need to check on them more frequently than other crops. 

Conclusion

Microgreens are one of the best plants to grow in aquaponics systems. They may be smaller in size, but they have an intense flavor and are packed with nutrients. They are also easy to grow, and aquaponics growers typically harvest these small plants around 7 to 21 days, which allows them to have a high turnaround.