Micro Nutrients or Trace Elements are just as important as the macro or secondary nutrients. These seven elements are required in even smaller amounts, but are beneficial for any plant. Other factors to keep in mind when considering your hydroponic nutrient schedule are the indirect implications and interdependence with other mineral elements and the symptoms and deficiencies each one can create. For example a Boron deficiency could result in an Iron deficiency. It’s important to keep on top of these additives to produce an optimal crop. The seven nutrients that are commonly referred to as micro nutrients are; Iron (Fe) Copper (Cu) Chloride (CI) Boron (B) Manganese (Mn) Molybdenum (Mo) Zinc (Zn) Iron – The photosynthesis catalyst Iron plays a part in the synthesis of chlorophyll and is required for photosynthesis. It’s fundamental to enzymes assisting in plant growth and the respiratory system. Iron is especially important in the early stages of the growth cycle and it’s crucial for Nitrate and Sulphur reduction and assimilation. Iron has low mobility and deficiency signs first show on the youngest leaves. In severe deficiency the leaves can turn completely white and develop necrotic spots. An iron deficiency is as bad for your plant as it is for your body resulting in poor growth with acute chlorosis and an effect like tip burn. Deficiency signs • Stunted or slow growth • Interveinal chlorosis in young leaves • Acute deficiency can cause the leaves to turn white and eventuate in necrotic spots Copper – The hormone mover Copper plays an important role in reproductive growth and pollen production. It’s responsible for hormone signalling and is involved in several metabolic processes. Along with being an important enzyme activator, Copper aids in root and Nitrogen metabolism and helps utilise proteins. Copper’s major role in photosynthesis makes this an element that plants cannot survive without. Deficiency signs • Wilted young leaves • Darker green coloured foliage • Limp terminal branches • Yellowing of the leaves (chlorosis) Chloride – The water and uptake mineral Chlorides main responsibility is the movement of water within plants (osmosis) Chloride balances the uptake of other minerals and in particular it assists potassium in controlling the stomata openings. It’s also thought to aid in plant metabolism and photosynthesis. A scientific note on Cl – Cholrine in its natural state is a gas so in a hydroponic environment it needs to be introduced as a soluble compound. Deficiency signs • Wilted leaves • Thick and stunted roots • Chlorosis over entire plant • Necrosis over entire plant in acute deficiencies • Possible bronze colourings in acute deficiencies Boron – The new development mineral Along with Calcium, Boron is essential in cell wall structure because of its ability to bind Pectin in the primary cell wall. Sometimes referred to as the micro nutrient with macro effects it plays an important role in general plant growth and can assist in new leaf production, bud development and root tip development. Boron is responsible for hormone regulation, sugar transport and synthesising some enzymes and it can increase flower or fruit production and retention. A deficiency in Boron could also cause an Iron deficiency and Boron aids in the movement of Calcium, but it can become the limitation on its movement. A deficiency can also negatively affect plants reproductive organs. Deficiency signs • Possibility of twisted or brittle leaves • Terminal bud death • Chlorotic leaf bases • Discoloured root ends and leaf tips • Stunted growth Manganese – Chlorophyll producer and water splitter Manganese plays out a role in photosynthesis through its involvement in enzyme activity and production of chlorophyll. Manganeses many roles in photosynthesis include the splitting of water, electron transport and nitrate assimilation. Manganese’s involvement with enzyme activation also aids the breakdown of carbohydrates and forms other compounds used for plant metabolism along with aiding in the formation of vitamins. Manganese is available from most natural mediums but is generally not plant available in its natural form. Once the element is absorbed by the plant it is relatively immobile. Deficiency signs • Necrotic leaves between veins • Drooping leaves • Foliage discolouration • Light interveinal chlorosis • Under developed root system • Grey spots in acute deficiencies Molybdenum – The metabolising element Molybdenum is an essential component of the enzymes responsible for the metabolism of nitrates into proteins or building amino acids. It aids in the use of Nitrogen and in Sulphur metabolism. The initial symptoms of deficiency are similar to those of Nitrogen deficiency but symptoms can show themselves differently depending on the type of crop in your hydroponic system, it’s helpful to know your plants requirements. Deficiency signs • Twisted young leaves turning upwards • Interveinal chlorosis Zinc – Critical to enzymes and Auxins Zinc is the only mineral element that is a component of all six enzyme classes and is a requirement for all plant life. It plays an extremely important role in the growth hormone Auxin which is associated with many growth and behavioural processes in plants. Zinc is associated with proper root development, starch regulation and carbohydrate formation. Zinc also helps other elements carry out their duties and is thought to play a role in DNA transcription. Low pH levels can lead to fast leaching of Zinc in your hydroponic medium resulting in deficiency. Deficiency signs: • Short internodes • Thickened leaves • Stunted leaf growth • Dis-coloured leaf tips, perhaps yellowing of younger leaves • Interveinal necrosis