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Nutrients and Additives Guide

There are literally hundreds of nutrient products available and it can get very confusing. 

All plants require basic nutrients - something high in nitrogen when in the vegetative stage and something high in phosphorous and potassium when in the flowering stage.

Micronutrients and trace elements are also needed for healthy growth. When growing in soil, many of these nutrients are naturally available, but when growing in a sterile medium like rockwool or clay, as is done in the majority of hydroponics systems, everything the plant needs must be added via a nutrient solution.

When it comes to choosing which nutrients and additives to purchase, we do recommend some brands over others but you don’t necessarily have to choose one brand and stick with them for everything; you can mix and match different products from different brands to suit different stages of growth. We believe that to achieve the best performance and yield possible with hydroponics, growers should combine a whole array of nutrients and additives to create a bespoke solution for their plants.

One general piece of advice is that for nutrients in hydroponics, less is more - always go half strength if in doubt and DO PURCHASE an EC or CF meter - VERY IMPORTANT! - in order to be able to accurately measure the concentrate of your nutrients. You also MUST purchase a pH meter in order to accurately maintain the pH level of the solution as it is delivered to the plants because different nutrients are more available to the plants than others at different pH levels. As plants consume the nutrients the pH level WILL change and therefore regular monitoring and adjusting with pH up and pH down will be a constant feature of your hydroponics maintenence schedule.

We stock only the very best brands of plant feeds and boosters, and there’s one to suit every method and style of growing. Whether you like to keep things simple with a single-part nutrient (like Growth Technology Ionic), or if you prefer to optimise every step of the way with a multi-part component nutrient brand (such as Mills or Remo Nutrients) we’ve got a nutrient brand that will be perfect for your needs and your pocket.

Hydroponics Nutrients Advice and Guidance


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.

Non-mineral elements

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.

Macro nutrients

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.

Micro nutrients

These hydroponics nutrients are required in smaller quantities by plants but they are equally as 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

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.


This element is shown to be beneficial to most plants and is essential in certain plants. Cobalt is known to be involved in protein synthesis and nitrogen fixation, both of which are important to plant growth and overall health.


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.

Nitrogen deficiency

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.

Phosphorus deficiency

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

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

Sulphur deficiency usual manifests itself visually with yellowing of the leaves and stunted plant growth.

Magnesium deficiency

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.

Boron deficiency

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.

Calcium deficiency

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

Copper deficiency most often manifests itself by causing small leaves that contain dead spots and noticeable brown areas near the leaf tips.

Iron deficiency

A serious iron deficiency will cause new leaves to appear either all yellow or white with green veins. However, a less severe deficiency will still cause slightly yellow leaves and browning of the leaf tips, as well as a decreased diameter of plant shoots and a yellow appearance of the stems near the tip.

Manganese deficiency

Manganese deficiency looks very similar to nitrogen deficiency, and can cause pale or yellow leaves and slight scorching and rolling / curling at the ends. It will be most noticeable on the youngest leaves of the plant.

Molybdenum deficiency

Only very small quantities of molybdenum are needed by the plant and deficiency is usually correlated with a low soil PH (of 5.5 or less). It commonly occurs with sulphur and phosphorus deficiencies and characteristics are similar to nitrogen deficiency, with pale green leaves and stunted growth and leaf size.

Zinc deficiency

Symptoms of zinc deficiency usually include small and stunted leaf growth that can sometimes also carry a yellow to grey hue. Older and narrow leaves may also drop off when plants are lacking zinc.


To ensure optimum plant growth in all growing environments plant nutrients have been specifically developed to encourage and boost plant growth during different stages of development as well as across different growing mediums. We only stock tried and tested nutrient solutions that contain the correct levels of the required elements and are proven to deliver great results. 

Grow and bloom nutrients

Most plant nutrients we stock from our chosen manufacturers come in both “grow” and “bloom” solutions. Grow solutions are usually developed for the vegetative stage of plant growth and also for continuous use on herby or leafy plants. Bloom solutions, on the other hand, contain the right mix of elements to boost growth during the productive flowering and fruiting stages.

Soil, coco, and hydroponics nutrients

As well as different solutions that accommodate the different stages of plant growth, plant nutrient manufacturers also develop specific nutrient mixtures to be used with either soil, coco, or hydroponic grows. Some manufacturers have different nutrients for each medium and some have developed hybrid blends that can be used across the board. Always check and read the descriptions on our site to see what nutrients will be most suitable for you.

Hard water and soft water

Depending on where you live you may have hard water or soft water in your area. Most of the plant nutrients we supply are tailored for use with either soft water or hard water, and some can be used with both types of water. It’s always worth checking whether you live in a hard water or soft water area before buying nutrients to ensure you buy solutions that are going to benefit your plants the most.

Organic and inorganic nutrients

We carry a range of both organic and inorganic nutrients to accommodate for all growing needs. If you prefer growing your plants the natural way then you’ll be pleased to know the organic nutrients we stock are all EU approved and are only ever derived directly from plant materials.

Inorganic nutrients have been carefully developed to deliver exactly the right ratio of the required plant nutrients. Although they carry the title “inorganic nutrients” most of the elements included in these products are derived from natural sources such as seawater or mineral deposits. They are only inorganic in the sense that they have been purified through the process of man-made extraction techniques.

If you’re unsure of whether to use organic or inorganic nutrients then it is important to realise key differences between these two types of nutrition. Inorganic products supply plant nutrients in mineral ion form which makes them readily available and often instantly absorbable by the plant roots. They are also very precise containing exact measurements of the needed chemical elements.

Organic nutrients work slightly differently and often give variable results. This is because the macro and micro nutrients contained within the organic substances first need to be broken down into their mineral ion form by micro-organisms, which can vary in their abundance in any given growing environment.

Some growers find that a combination of organic and inorganic nutrients is an effective feeding strategy for their plants, particularly the growers that use soil. This is due to the fact organic nutrients can increase the cation exchange capacity (CEC) of soil, prevent the washing away of inorganic nutrients each time plants are watered.


Aside from the core plant nutrients needed during the different stages of growth, there are also a range of additives available that contain the elements needed to increase plant strength and boost plant performance. There are also plant care nutrients that are designed to assist and protect your plants, such as helping plants quickly bounce back from common stress factors like transplanting.


There are several common additives that many growers choose to use. For example, “PK boosters” are an often used flowering / fruiting stage nutrient additive that aren’t essential to plant survival, but do contain high concentrations of potassium and phosphorus; two elements that plants need large amounts of during this stage of growth.

Other common nutrient additives include root stimulators that encourage the development of strong, vigorous roots and bloom stimulators that help plants ramp up their energy levels during the flowering and fruiting stage to increase production and overall yields.

Plant care

There are numerous care products that offer a range of beneficial effects to your plants. For example, solutions containing high numbers of specific enzymes can be used to break down dead root material to provide extra nutrition for your plants, more aeration for your roots, and allowing for more efficient uptake of vital nutrients.