One of the benefits of aquaponics is that you can grow just about any plant, 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 planted into your grow beds, floating boards, or PVC pipes.
Planting in aquaponics can be very simple. In most ways, you can treat it as you would a traditional garden bed. However, you need to know a few basic things before you start planting in your aquaponic garden.
Aquaponics Planting vs. Traditional Planting Method
Traditional planting is an old farming method that relies heavily on the soil and direct sunlight and rainfall for nourishment. In this method, farmers tend to supplement the produce with fertilizers, pesticides, and insecticides to improve plants health and harvest,
Aquaponics is a modern planting method that eliminates the use of soil. Instead of growing plants on land, aquaponics uses fish waste to provide nutrients to the plants. Aquaponics is a recirculating system where fish produce fish waste that is converted by the bacteria into nutrients for the plants. In return, roots filter the water to remove toxins for the fish to live.
Advantages of Aquaponics
- The water used in aquaponics is much lower than in traditional plant cultivation. Aquaponics uses only about 10% of the water needed to grow the same plant in soil.
- Traditional planting requires extensive land areas, while aquaponics does not need extensive land to set up. You can set up an aquaponics system in basements, rooftops, garages, or a small backyard.
- Aquaponics planting is year-round, so it has a higher yield compared to traditional planting.
- Aquaponics eliminates the use of chemicals such as fertilizers, pesticides, and insecticides. So you can be sure that aquaponics products are healthy and chemical-free.
- Plants grown in aquaponics grow faster than other planting methods because it has more access to the nutrient-rich water.
Source of Nutrients for Aquaponics Plants
It is essential to feed the fish a balanced and complete diet to ensure that plants will not suffer from nutrient deficiencies. However, sometimes a perfectly balanced aquaponics system may become deficient in specific nutrients, like iron, potassium, or calcium deficiencies. Feed pellets are a complete food for the fish, but not necessarily everything needed for plant growth. Fish do not need the same amount of iron, potassium, and calcium that the plants require. This is why nutrient deficiencies in aquaponics systems occur.
Nutrient deficiencies can be problematic for plant production, but there are solutions available. Iron can be added as chelated iron if an iron deficiency occurs, while calcium and potassium are added when buffering the water to correct the pH. These are added as calcium hydroxide or potassium hydroxide or as calcium carbonate and potassium carbonate.
What and When to Grow in Aquaponics
Different plants grow under different conditions. In growing plants in your aquaponics system, it is essential to consider what type of grow bed you’re using. Some plants can thrive and grow in a floating raft, like lettuce and leafy greens, while root vegetables and fruiting plants grow better in media beds.
Another thing to consider is your system, and if your system is new, it is best to grow plants that require lower nutrients like lettuce, salad greens, and herbs. However, once your system is mature (6 months old and up), you can start growing fruiting and flowering plants like tomatoes and cucumber. Fruiting and flowering plants require high nutrients. So it is best to wait before planting them in your system.
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. 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.
It is best to plant a mixture of vegetables in your aquaponics system. Plant 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. Water and oxygen are taken through the seed coat when the seed is exposed to the appropriate condition. 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 coat breaks down. Soaking or scratching the seeds will help break down the seed coat and help the seed germinate faster. Over-watering, not enough oxygen, planting seeds too deeply, and dry conditions can cause poor germination.
Three 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, where they grow media like pebbles or gravel to support the seed’s growth.
Spread the seeds out evenly, push them down under the top dry layer of your growing media, and then wait for them 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.
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 in 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.
There are different starter plugs, such as rock, wool or peat. Compressed peat, rock wool, and paper towels are the most common because they are 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 used by dipping the cut end into the rooting hormone.
Transplanting Seedlings
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 ground, 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 help because the transplanting process can sometimes damage the plant’s roots. The rooting compound will encourage fast regrowth.
Tips for Planting in Aquaponics
- Keep in mind that plants need space to grow, so give your plants plenty of room to grow and bear fruits.
- If you are not sure how big your plant will grow, check the seed packet or tag, they have information about the size of the full-grown plant and the spacing they need.
- Be careful when planting or replanting the seedling. Plant roots are very sensitive, and it will take a few days for a new plant to settle into its new environment.
- Tend your aquaponics plants as you would with your normal gardening method.
- Always monitor and maintain the water quality of your system to ensure healthy fish. Healthy fish means lots of fish waste for the plants.
- Enjoy planting and harvesting the plants in your aquaponics system.