Aside from adequate light and water, plants need to be fed a number of essential chemical elements to grow, thrive, and survive. In outdoor environments, most of these elements are available to plants organically through soil and other natural processes. However, when growing plants indoors it’s up to you to use the right mixture of plant nutrients at the right time to ensure healthy growth and to improve the performance of your plants.
Three of the key elements needed by plants; Hydrogen, Carbon, and Oxygen, are readily available to through air and water. The rest need to be provided by you, the grower, throughout the plant growth cycle.
In the scientific field, this wavelength window is known as Photosynthetically Active Radiation (PAR for short), and it’s this range that you need to replicate indoors in order to mimic sunlight and provide the perfect environment to grow a great, healthy crop.
Macro nutrients play a huge and vital role in plant development and they are required in large quantities to ensure healthy growth. Nitrogen, Phosphorus, and Potassium are the primary macro nutrients a plant needs. Other important secondary macro nutrients required are Sulphur, Calcium, and Magnesium. Silicon is also a macro nutrient used by plants, but it is not considered essential.
These hydroponics nutrients are required in smaller quantities by plants but they are equally important to healthy plant growth as the macro nutrients. Micro nutrients that a plant needs are Iron, Molybdenum, Boron, Copper, Manganese, and Zinc. The micro nutrient Sodium can also be beneficial to plant health.
Beneficial elements, although not essential to plant growth, are recognised to stimulate growth and improve overall health, especially during certain stages of plant development. Out of the above macro and micro nutrients, both Silicon and Sodium are considered beneficial elements. Two elements not in the above list, Cobalt and Selenium, are also known to be beneficial elements in plant growth.
Each element, whether it’s a macro, micro, or beneficial element, serves a particular function in plant growth and development. Here’s how each contribute:
This macro element is an essential component of all proteins and is necessary to ensure the formation of chlorophyll, amino acids, and co-enzymes.
A macro element known to be vital in sugar, phosphate, and energy production, Phosphorus serves several functions and is particularly important in the flowering and fruiting stages, as well as for stimulating root growth.
This element is required in large amounts for protein synthesis. Potassium helps in the manufacture of essential sugars and starches, and it also encourages plants to grow healthy roots and a sturdy structure.
This essential element plays a key role in the formation of chloroplasts and protein synthesis. It helps with water uptake and during the seeding, and flowering / fruiting stages of plant growth. Sulphur also acts as an organic fungicide which is beneficial throughout the entire growth cycle.
Although considered a beneficial element, silicon has a role in many vital plant functions. It is known to protect plants from pests and disease, it strengthens cell walls and increases plant health and productivity, and is shown to improve root mass and overall yields.
This macro nutrient is a vital part of chlorophyll. It also is needed to make oxygen during photosynthesis and is important for catalysing the growth process.
Boron serves a primary function in cell wall formation, but secondary functions include sugar transport, cell division, and the synthesising of a number of key enzymes.
Calcium, like Boron, also aids the formation of healthy cell walls and activates required enzymes. It also plays a role in photosynthesis and regulates the transport of other key nutrients.
Iron is a necessary element for photosynthesis and is also a required element for the synthesis of chlorophyll; both processes are essential for healthy plant growth.
This micro nutrient plays a role in enzyme production and in building amino acids, all of which can stimulate plant growth and increase health.
Copper is a micro nutrient that plays several key roles in plant development. It is important and necessary for photosynthesis; it is involved with many enzyme processes, and helps form cell walls and sturdy plant structures.
This element is plays a role in photosynthesis and is also important in the building of chloroplasts.
Although sodium is considered a beneficial element and not an essential element, it still helps plants thrive and it can act as a substitute for potassium for some plant functions, such as enzyme activation and photosynthesis.
Zinc is a basic constituent of many plant enzymes and it also plays a key role in the formation of chlorophyll and nitrogen metabolism.
Another beneficial element, selenium has been shown to help plants in several ways, such as increasing water retention during drought, increasing tolerance to oxidative stress, protecting plants against pests, and delay senescence (the process of aging and death).
If you’re not using the right hydroponics nutrients on your plants then chances are they will develop some form of element deficiency. When a plant isn’t receiving enough of one or more of the chemical elements it needs it can often be spotted visually on the plant.
If you know what you’re looking for with nutrient deficiencies then you’ll know what you’ll need to do to bring your plants back to full health. Deficiencies only arise with the essential chemical elements and the beneficial elements silicon, sodium, cobalt and selenium will not cause a noticeable deficiency if your plants are not receiving them.
A deficiency of nitrogen often results in slow or stunted plant growth and a condition called chlorosis (where plants produce insufficient amounts of chlorophyll). As chlorophyll gives leaves their green colour, chlorosis can be identified by pale or yellow leaves. Nitrogen deficiency also usually causes the stems to appear purple in colour in certain areas.
This deficiency usually manifests itself as an intense dark green colouration of the leaves. If a plant is seriously lacking phosphorous then the leaves can have a purple or blue hue and show signs of necrosis and decay. A phosphorous deficiency will always be noticeable on the older leaves first.
Potassium deficiency will often show several tell-tale signs, including wilting, chlorosis, brown spotting, and an increased risk for frost / heat damage and diseases. It is usually noticeable on the older leaves first.
Sulphur deficiency usual manifests itself visually with yellowing of the leaves and stunted plant growth.
This deficiency is usually characterised by interveinal chlorosis, a condition which often causes interveinal reddening or yellowing of the older plant leaves whilst the leaf bases still stay green. Leaves may also appear thin and brittle and may curl up at the ends.
Often noticeable on the youngest plant leaves, visual signs of boron deficiency include red, bronze, or scorched looking leaves that are thin and brittle. It can also cause flat top plants through the development of lateral shoots and uneven ripening and heart rot of fruits during the productive stage of growth.
Again noticeable on the younger leaves, calcium deficiency is often characterised by distorted leaves, stunted plant and root growth, and curled leaf tips.
Copper deficiency most often manifests itself by causing small leaves that contain dead spots and noticeable brown areas near the leaf tips.