How To Start Planting In Aquaponics
Planting in aquaponics can be very simple. In most ways, you can treat it as you would a traditional garden bed. However, there are a few basic things you need to know before you start planting in your aquaponic garden.
There are many benefits of aquaponics. You can grow just about any plants in your aquaponics system such as lettuce, spinach, carrots, fruiting plants like tomatoes and strawberries, and even herbs and flowers. Plants can be grown from seeds to seedlings and can be planted into your grow beds, floating boards, or PVC pipes.
Once you have your system assembled, you need to start “cycling” your system. The cycling process is necessary for establishing bacteria in your system.
Without the bacteria in your system, the nitrogen cycle will not occur. The nitrogen cycle transforms ammonia from fish waste and decomposing fish food into nutrient-rich food for the plants. The nitrifying bacteria are needed for this transformation to take place. The nitrifying bacteria convert ammonia into nitrites and nitrites into nitrates, which is used by the plants as food. (1)
Once you have cycled your new system, you can start planting your seedlings in your aquaponics system. The nutrients needed by the plants will be fully available once your system is fully cycled.
What and when to grow in Aquaponics
Different plants thrive under different conditions. When growing plants in your aquaponics system, it is important to consider what type of grow bed you’re using. Some plants can thrive and grow in a raft based aquaponics system like lettuce and leafy greens, while root vegetables and fruiting plants grow better in media-based aquaponics systems.
When deciding what plants to grow in your aquaponics system, it is important to choose varieties of vegetables that will grow best in your climate. Knowing the best plants to grow in your aquaponics system is necessary for your system's success.
Temperature is hard to control even if you’re growing in a greenhouse, and plants thrive better when the temperature matches their typical habitat. So grow cold-weather crops in colder months and warm-weather crops during summer. (2)
Carefully schedule your planting times, and stagger your projected harvest so that your produce doesn’t ripe at one time, for a sustainable food supply. If you’re planning to grow large quantities of the same vegetables, stagger their growing periods so you will harvest by batches and avoid overloading of nutrients in your water, which could stress the fish once your vegetables are harvested.
It is best to plant a mixture of vegetables in your aquaponics system. Plant some fast-growing plants like lettuce and slow-growing plants such as herbs, tomatoes, peppers and dark leafy greens like kale and swiss chard. Using succession planting allows some of your plants to mature and be harvested while the newer ones are growing and coming in behind. Succession planting will ensure that you always have plants taking nutrients from the water all the time.
How to Germinate Seeds
All seeds need water, oxygen, and proper temperature to germinate. When the seed is exposed to the proper condition, water and oxygen are taken in through the seed coat. Then the embryo’s cells will enlarge, and the seed coat will break open for the root to emerge, followed by the shoot that contains leaves and stems.
Some seed coats are so hard that water and oxygen can only get through when the coating breaks down. Soaking or scratching the seeds will help break down the seed coat and will help the seed germinate faster. Over-watering and not enough oxygen, planting seeds too deeply, and dry conditions can cause poor germination. (3)
Seed Starting Techniques
Below are the three main ways of starting seeds in aquaponics.
1. Direct Sowing
Some seeds can be sown directly in your grow beds. This method is used in a media-based system, and the grow media like pebbles or gravel will provide support to the seed growth.
Spread the seeds out evenly and push them down on under the top dry layer of your growing media, then wait for it to germinate naturally. This method works well for leafy greens and herbs like lettuce and chard. However, some seeds germinate better than others under these conditions, so you need to sow many seeds expecting not all of them will germinate. (4)
The advantage of the direct sowing method is that you need not transplant your plants to your grow bed, eliminating the possibility of damaging the plants’ roots.
2. Starter Plugs
Starting seeds in a separate media plug and placing it to your grow bed is a great way to arrange your plants in your grow bed. Using starter plugs is best used for seeds that are harder to germinate or need more time and care like tomatoes, peppers, and eggplant. Once the seeds germinate to your desired size, they can be transferred into your grow bed by making a small hole and gently placing the seedling in it. Then carefully cover the plug with your grow media. (4)
There are different starter plugs, such as rock wool or peat. Compressed peat, rock wool, and using paper towels are the most common because it is inexpensive, sterile, and easy to find.
3. Cuttings and Cloning
Some plants can be grown in aquaponics by sticking cuttings directly into your grow bed. Fast-growing herbs like basil and mint will sprout from cuttings, making them a great way to plant without using seedlings. Rooting hormones that induce new roots can be applied by dipping the cut end into the rooting hormone.
You can get seedlings from a store or start seeds yourself. Once your seeds sprout, good soil, and strong light will help them grow. When transplanting your seedlings from the soil, fill a small container with water, and gently rinse the dirt off the roots before placing the plant in the media deep enough for the roots to touch the water. Applying rooting compounds can be helpful because the transplanting process can sometimes damage the plant’s roots, and the rooting compound will encourage fast regrowth. (4)
Growing Guidelines for 5 Common Aquaponics Plants
Plant spacing: 18-30cm
Germination time: 24-32 days
Temperature: 15-22 °C
Plant height and width: 20-30 cm; 25-35 cm
Growing Instructions: Seedlings can be transplanted in your grow bed at three weeks when plants have at least 2-3 true leaves. You can add phosphorus supplement fertilizer to the seedlings in the second or third week to avoid plant stress during transplant.
When transplanting lettuce in a colder climate, expose your seedlings into colder temperature and direct sunlight for 3-5 days for a higher survival rate. When transplanting in warm weather, place a light sun-shade over the plants for 2-3 days to avoid water stress.
To achieve crisp, sweet lettuce, maintain a high nitrate level in your system. If you’re growing in a grow bed, plant the new lettuce where the taller plants will partially shaded them.
Harvesting: You can harvest as soon as the heads or leaves are large enough to eat. It is best to harvest early in the morning when the leaves are crisp and full of moisture and chill quickly to maintain freshness. (5)
2. Swiss Chard
Plant Spacing: 30-30 cm
Germination time and temperature: 4-5 days; 25-30 °C
Growth time: 25-35 days
Temperature: 16-24 °C
Light exposure: full sun (partial shade for temperatures > 26 °C)
Growing Instruction: Swiss chard seeds produce more than one seedling, so it is important to do thinning as seedlings grow. As plants grow, older leaves can be removed to encourage new growth.
Harvesting: Swiss chard leaves can be cut continuously when they reach harvestable size. Removing larger leaves encourages new growth. (5)
Plant Spacing: 15-30 cm
Germination time and temperature: 8-10 days; 20-25 °C
Growth time: 20-30 days after transplant
Temperature: 15-25 °C
Light exposure: partial shade at >25 °C
Growing instructions: Initial germination can be difficult when growing parsley, which can take 2-5 weeks. To speed up germination, you can soak the seeds in warm water (20-23 °C) for 24-48 hours to soften the seed husks. After soaking, drain the water and sow seeds into propagation trays. After 5-6 weeks, transplant the seedlings into your grow bed.
Harvesting: Harvesting begins once individual stalks of the plant are at least 15 cm long. Harvest the outer stems from the plants to encourage growth. Parsley dries and freezes well. (5)
Plant spacing: 40-60 cm
Germination time and temperature: 4-6 days; 20-30 °C
Growth time: 50-70 days until the first harvest, fruiting 90-120 days up to 8-10 months
Temperature: 13-26 °C at night; 22-26 °C day
Light exposure: full sun
Growing Instruction: Transplant seedlings into your grow bed 3-6 weeks after germination when the seedlings are 10-15 cm. Use stakes or plant support in transplanting to prevent root damage. In transplanting your seedlings, avoid water-logged conditions around the plant collar to reduce the risk of any diseases. Once your tomato plant is about 60 cm tall, you can prune the unnecessary upper branches and remove the leaves from the bottom of the main stem to favor air circulation and reduce fungal incidence. You can also remove the leaves that cover each fruit branch before the fruits ripen to favor nutrition flow to the fruits and to speed up maturation.
Harvesting: Harvest your tomatoes when they are firm and fully colored for better flavor as the fruit will continue to ripen after harvest. (5)
Plant spacing: 30-60 cm
Germination and temperature: 8-12 days; 22-30 °C ( seeds will not germinate below 13 °C)
Growth time: 60-95 days
Temperature: 14-16 °C
Light exposure: full sun
Growing Instruction: Transplant seedlings with 6-8 true leaves. You can use stakes or vertical strings hanging from iron wires to support bushy or heavy-yielding plants. For red sweet peppers, leave the green fruits on the plants until they ripen and turn red. Reduce the number of flowers in the event of excessive fruit setting to favor the growing fruits to reach adequate size.
Harvesting: Harvest your peppers when they are large enough to be harvested. To improve your plant's vitamin C level, leave peppers on the plants until they ripen fully by changing color. Peppers can be stored fresh or dried. (5)
Plants are one of the main components of your aquaponics system, so it is important to take care of them. Plants filter the water in your system and provide food to you and your family. The fun part of gardening is experimenting and learning, so don’t worry if you make mistakes on the way because it’s all part of the process. Once you get to the right steps, you’ll have healthy, tasty, and fresh plants. Feel free to leave your comments below and subscribe to our newsletter to get new updates on aquaponics.
- Aquaponics, Aquaponics Plants, Aquaponics vegetables, Lettuce, Planting, Seedling, seeds, strawberry, tomatoes