top of page

Plant nutrients and Aquaponics!

Like humans, plants are similar. Plants need a range of nutrients to survive and thrive. These nutrients are broken up in two simple categories; Macro and Micronutrients.

Plants use macronutrients in larger amounts. They also may need Micronutrients in smaller amounts.

What are Macronutrients and what do they do?

Nitrogen- is probably the most important element for plants. Nitrogen gives plants energy to grow, fruit and flower. Nitrogen is part of the chlorophyll molecule, which gives plants their green colour and is involved in creating food for the plant through photosynthesis.

Phosphorus- Phosphorus regulates protein synthesis. Phosphorus is important in cell division and development of new tissue. Phosphorus helps transform energy in plants.

Potassium- has several functions in plants. During photosynthesis potassium regulates CO2 uptake, activates enzymes, uptake and loss of water, resistance to drought and much more.

Calcium- is responsible for holding together the cell walls of plants. When calcium is deficient, new tissue such as root tips, young leaves, and shoot tips often exhibit distorted growth from improper cell wall formation.

Sulfur- helps form important enzymes and assists in the formation of plant proteins.

Magnesium- Magnesium is the powerhouse behind photosynthesis in plants. In short, magnesium is required to give leaves their green color.Magnesium is also used by plants for the metabolism of carbohydrates and in the cell membrane stabilization.

Carbon- Plants use carbon dioxide during photosynthesis, the process whereby the plant converts the energy from the sun into a chemical carbohydrate molecule. Plants use this carbon chemical to grow.

Oxygen- In the process of photosynthesis, plants take in CO2 (carbon dioxide) from the air and combine it with water absorbed through their roots. They use energy from sunlight to turn these ingredients into carbohydrates (sugars) and oxygen, and they release extra oxygen to the air.

Hydrogen-used by plants which combine it with carbon during the photosynthesis process and release oxygen into the atmosphere which is used by all living beings.


Boron- Boron helps control the transport of sugars in plants. If Boron levels are low plants may appear healthy but will not flower or fruit

Chlorine- chlorine is important for plant photosynthesis as it is involved in the opening and closing of stomata.

Copper- Without adequate copper, plants will fail to grow properly. Copper commonly influence copper are the soil pH and organic matter.

Iron-The role of iron in plants is as basic as it can get: without iron a plant can’t produce chlorophyll, can’t get oxygen and won’t be green.

Manganese- Many processes are dependent on this nutrient, including chloroplast formation, photosynthesis, nitrogen metabolism and synthesis of some enzymes. This role of manganese in plants is extremely crucial. Deficiency, which is common in soils that have neutral to high pH or a substantial deal of organic matter, can cause serious problems with plants.

Molybdenum- In plant growth, it helps in the nitrogen, oxygen and sulfur cycles.

Zinc- The function of zinc is to help the plant produce chlorophyll. Leaves discolor when the soil is deficient in zinc and plant growth is stunted.

How do fish produce nutrients?

In Aquaponics fish produce waste contains nitrogen in the form of ammonia (too much of which can be toxic to fish), along with a variety of nutrients like phosphorus and potassium. Nitrifying bacteria that live in the gravel in the fish tank and on the tank walls convert the ammonia first into nitrites and then to nitrates which the plants can use. The water in the tank, which contains ammonia, nitrites, nitrates, phosphorus, potassium, and other micronutrients, is continuously pumped into a grow bed where the plants are located. The plants remove the nutrients from this water, and nitrifying bacteria in the grow bed (working together with the tank filter) clean the water by converting excess ammonia into nitrates, which plants use to grow. The clean water is then sent back into the fish tank.

The grow bed and plants act as a biofilter, cleansing the water so that the fish remain healthy. In smaller, backyard aquaponics systems, the grow bed sits on top of the fish tank and the cleansed water from the grow bed drips back into the tank. In aquaponics, the fish, plants, and beneficial bacteria all depend on each other to live. Watch this video to learn more about commercial aquaponics

63 views0 comments
bottom of page