When it comes down to it there are 20 mineral elements essential/beneficial for healthy plant growth
The following elements are supplied via the air and water
- Carbon (C)
- Hydrogen (H)
- Oxygen (O)
The following Macro-nutrients are needed in high volumes though the
required levels of each fluctuate through out the grow cycle depending on
needs . These elements are not generally present naturally in high
enough ratios in your average soil and hydroponic mediums contain no
nutrients at all , which means they must be supplied through the form
of some sort of nutrient or natural source mixed into or watered into
- Nitrogen (N)
- Phosphorus (P)
- Potassium (K)
- Calcium (Ca)
- Magnesium (Mg)
- Sulfur (S)
Nitrogen : Nitrogen
is what we generally call a building block element even when it's not
necessarily needed itself it's relationship with other elements makes
it a key to successful growth, it is a major component of proteins ,
hormones, chlorophyll, vitamins and Nucleic acids. Nitrogen plays a
major part in stem and leaf growth as well as being closely tied into
the uptake of other nutrients. A build up or too high of a level of
nitrogen can be detrimental to growth by delaying flowering and
fruiting as-well as locking out other nutrients that would otherwise be
available. Deficiencies can reduce yield , cause yellowing of the
leaves , stunt growth and stress the plants ammune system.
Phosphorus: Is required for seed production, photosynthesis, fruit/flower formation , bulking up , protein synthesis and just about ALL aspects of growth and metabolism in plants. A failure to supply the necessarily levels of phosphorus can lead to deficiencies very quickly , some of the symptoms of this deficiency include stunted plant growth, a reduce in yields of fruit and flowers , as well as incorrect or whispy formation of flowers . Too much Phosphorus , can cause problems with the uptake of zinc aswell as other elements so ensure that if your needing to compensate to high levels that you should also balance out your zinc levels at the same time.
Potassium: Potassium is required for sugars , carbohydrates, cell division , protein synthesis and phloem transport. It acts as an activator to many enzymes that are required in photosynthesis and respiration. It has also been shown to help adjust water balance , improve stem rigidity , cold hardiness and enhance flavor. Deficiencies result in low yields, spotty and or curled leaves and a potential scorched or burn look to the leafs.
enzymes , is a structural component of cell walls , influences water
movement in cells and is necessary for cell growth and division .
Calcium is required for membrane function of all cells , Some plants
also need calcium in order to uptake Nitrogen and other minerals. The
balance is important though as the right amount is helpful for the
uptake of other elements where as to much can have the exact opposite
effect and lock those same elements out. Symptoms of deficiencies
include black spots on the leaves and potentially fruits
Sulfur: is a structural component of amino acids , enzymes, proteins and vitamins. Sulfur is essential in respiration and lipid metabolism and has been shown to have a direct correlation with improving plant flavour in many vegetables. Sulfur is readily lost by leaching from soils and should be applied with a nutrient formula. In high enough doses it can start to cause issues with the uptake of other elements though generally a sulfur deficiency is caused due to either a total lack of sulfur or another problem causing the lockout.
Magnesium: is a critical structural component of the chlorophyll molecule and is necessary for functioning and or activation or plant enzymes to product carbohydrates, sugars, proteins and fats. Magnesium is also vital in the production of healthy and correctly structured fruits and flowers and seeds . In essence magnesium is essential to all the metabolic pathways in plants. Deficiency symptoms include yellowing between the veins of older leaves and drooping leaves aswell as other symptoms which are best covered by the chart linked below.
Although the above cover your major nutrient needs there are also
certain required micro-nutrients which are only required in trace
amounts and are considered to play more secondary roles and " behind the scenes stuff "
- Boron (B)
- Chlorine (Cl)
- Copper (Cu)
- Iron (Fe)
- Manganese (Mn)
- Zinc (Zn)
- Molybdenum (Mo)
- Nickel (Ni)
Boron: plays an essential role in membrane integrity , calcium uptake , root elongation nucleic acid metabolism, pollen formation, movement of hormones and cell wall synthesis. It is thought to effect asmany as 16 functions of plants , so though it is only needed in very trace amounts it is an important element in a successful garden. Some symptoms of deficient plants are death in young leaves, plants can fail to set seed or produce viable pollen , fruit formation is effected , discolored roots , crackled and flecked brown spots on your leafs.
Chlorine: is involved in the regulation of movement of water and other solutes into and out of cells . Chlorine is essential for cell division in leaves and in the regulation of opening and closing stomata it is also involved in photosynthetic transfer of oxygen and nitrogen metabolism. Symptoms of issues can include yellowing of the veins in older leaves, wilting of the leaves and stunted root growth. Too much chlorine is very detrimental to plants as with build up it can become a deadly toxin to the plant not to mention it's ability before those levels to effect nutrient uptake
Copper: is an integral component of several needed enzymes and other critical biological proteins . It is required for photosynthesis , respiration, pollen grain formation and in carbohydrate, nitrogen and lipid metabolism. How copper is introduced into the system is quite important , particularly in the case of organic growers as Copper has a tendency to tightly bind to other organic compounds which can make them unavailable or less reliably available despite being present in the soil. This can become a larger issue if build up occurs as high levels of copper being released can be quite toxic to plants. Symptoms of a copper deficiency include necrosis of new growth tips, stunted growth and some leaves may develop black necrosis spots . Copper deficiency is not a Huge deal in vegetative growth however in flower it can have a huge impact on flower/fruit and seed production.
Iron: is a component of many structural and enzyme proteins. It is essential for electron transport and chlorophyll biosynthesis. It is therefore required for photosynthesis and respiration . A well known symptom of iron deficiency is a yellowing building out from the veins of the leaves. It is probably one of he more common of the micro-nutrient deficiencies though is often caused by pH issues rather than an actual lack of iron provided a full spectrum nutrient is being used or the organic equivalent
Manganese: Its main role is to play a part in the activation of many enzymes and assists other elements being taken up. Manganese is required for respiration and both carbohydrate and lipid metabolism. Symptoms of a deficiency can include necrosis spots on leafs and black necrosis of new tips
Zinc: is essential for DNA replication , gene expression , protein synthesis , IAA synthesis, membrane integrity and carbohydrate metabolism. Deficiency symptoms can include a reduction in leaf size, white leaf tips and shortened inter-nodes.
Nickel: has recently been determined to be an essential trace element for plants by a group of scientists at the United States Department of Agriculture and the Agricultural Research Service . It is Required for the enzyme urease , which most plants use to break down urea into usable forms of nitrogen and is also necessary for iron absorption . Plants grown without a suitable supply of nickel will gradually reach a deficient level at the time of sexual maturity which will of-course effect any planned reproduction.
Molybdenum: is a structural component in the enzyme nitrate reductase that reduces nitrates to ammonia . This enzyme is found in all higher plants . Many plants reduce atmospheric nitrogen to ammonia via bacteria location in the roots . These bacteria use the enzyme nitrogenase, which also contains molybdenum. Without adequate levels the synthesis of proteins is blocked , plant growth may stunt and seeds may not form completely . Some symptoms of molybdenum deficiency are stunted seedling growth, and many signals that would point you to nitrogen. The trace elements needed are generally found in decent soil mixes aswell as most full spectrum nutrients , so like many elements your generally only going to see this one when you have other lock out or ph issues , or if your trying to over compensate due to concern you can ofc put too much in
Studies have shown
that other elements can be beneficial to plant growth though the
distinction between beneficial and essential is often a hard line to
draw . Like in the case of Cobalt where although Cobalt as an element
isn't essential itself it greatly assists with Nitrogen uptake when
found in the correct ratios. The three main ones in relation to our needs are
- Sodium (Na)
- Silicon (Si)
- Cobalt (Co)
Sodium: is involved in water movement throughout the tissue of the plant and ionic balance high levels however can throw this balance out , It is an element that is often found in tap water though rarely in it's available form. Being a very reactive element the incorrect ratios can be very detrimental to the plant if it is allowed to build up.
Cobalt: is required for nitrogen fixation and root nodules , because of this deficient levels can easly result in nitrogen deficiency.
Silicon: deposited in cell walls , has been found to improve heat and drought tolerance and increase resistance to insects and fungal infections. Silicon, acting as a beneficial element can help to compensate for toxic levels of manganese, iron, phosphorus and aluminum aswell as build a barrier against zinc deficiency . Plants with a regular supply of soluble silicon produce stronger, tougher cell walls creating a barrier from mouth of sucking insects . Tests have also found that silicon can be deposited by the plants at the site of a fungal infection to combat the infection of the attacking fungal disease . Much of the silicon found in the ground is not naturally usable as it is found in solids hard to break down easily however studies have shown that if you give your plant water , that it is just about impossible in most area's of the world to totally deprive your plant of silicon , as even distilled water contains a certain amount, it can however be helpful to add additional silicon to the system for extra benefit
With everything above considered in my opinion the best approach to feeding would be to not limit yourself to just the nutrients essential for survival but to also add beneficial elements at low levels to optimize growth. It will also often mean that as you get things worked out your using less of your primary nutrients due to the fact they are being used more efficiently
Fortunately this is quite an easy task to achieve with many products on the market made specifically to suit all sorts of plants containing pretty much all you need for health growth
The information in this document has been put together with the assistance of experience , several books and websites
A special thank you to Hemp Diseases & Pests: Management & Biological Control and Maximum Yeild for their reference information