Greenfields Hydroponics UK - Plant Nutrients and Additives

Nutrient Solution Information
The Basics
Plants which are grown hydroponically are usually planted in an inert media, such as Rockwool, Clay pebble or Perlite, the inert media provides structural support for the plants growth and aeration for good root development. As the media provides no nutrition, the plant's food must be supplied additionally; most hydroponics plant feeds are in the form of liquid fertilisers which can be mixed directly with water and supplied to the plants media as a nutrient solution. The nutrients solution is the sole source for a number of mineral elements, it is important that you use nutrients that are made for hydroponics and that the water is good quality. Tap water is usually fine.
As a result nutrients are the key factor in soiless gardening. A complete and balanced formula is needed to obtain the best results from your system. In soil based gardening it is impossible to know how little or how much of a particular mineral is available to the plants. In hydroponics we must provide all the minerals necessary for successful plant growth. We therefore use feeds that contain all of the 14 essential minerals required. For these reasons ordinary soil based plant foods are not suitable for use in hydroponic systems. However, hydroponic nutrients are especially good for use on soil based plants due to the complete feed they represent.
In general there are 2 types of nutrient available to the hydroponic grower. A 'Grow' mix and a 'Bloom' mix. The 'Grow' is used for young plants, plants in vegetative growth and for plants which do not flower or produce blooms or fruit. The 'Bloom' is used for flowering and fruiting when necessary.
Some nutrients are also supplied in Hard water and Soft water formulation. In the UK most water is termed as being 'hard' and as such contains high levels of bicarbonates. In these circumstances it is better to use a hard water mix which has less of the minerals that are already found in the 'hard; water.
All of the nutrient brands stocked contain everything that a plant requires in exactly the right ratios to obtain maximum results. All the nutrients are mineral elements that are water soluble so as to be readily available to the plants in the system.
Nutrient ratios are commonly noted as NPK ratios, each representing the ratio of Nitrogen (N), Phosphorous (P) and Potassium (K). These are the three main minerals required for plant growth, but are not the only ones!
Measurement of Nutrient Strength
Different plants need differing strengths of nutrient mixes through the growth cycle, especially if fruiting of flowering is to occur. To measure the strength of a solution a EC (Electrical Conductivity) meter is needed. CF and EC is the measurement of how much dissolved nutrient is contained within the solution. The higher the number the stronger the nutrient solution is. In general, leafy vegetables like lettuces will need a weaker strength solution than a fruiting or flowering plant, such as peppers, tomatoes or roses.
What is pH?
pH is a measure of how alkaline or acidic the nutrient solution is. The pH scale runs from 0 to 14, with 0 to 7 being acidic and 7 to 14 being alkaline. The majority of plants prefer the pH between 5.5 and 7.5, beyond this range some nutrient elements will be unavailable to the plants, the optimum pH being between 5.8 and 6.3. Most tap waters are between pH 7 and 8.
Regulating pH levels
pH regulation is an essential practice for the plant grower: It enables mineral salts availability and chelates stability, two primary conditions for a good absorption of nutritive elements by the plant.
pH Down brings certain amount of nutritive elements essential for cuttings and seedlings, and beneficial to the plants all along its life cycle:
* Nitrates in a form slowly assimilated by the plant and harmless to the flowering process. * Phosphates for flowering, but also for healthy roots, lush foliage and harmonious growth. * Plus some magnesium, sulphur and microelements. To understand pH adjusters you must first understand what pH is. pH is a measurement of how acidic or alkaline a substance is. pH is most acidic at the lowest pH reading on the pH scale - pH '0' & most alkaline at the highest end of the scale - pH '14' as the value rises upward from zero, the strength of the acid reduces until at pH '7.0.
At pH 7.0 it is neither acid nor alkaline but in a neutral state. pH is a result of the balance or imbalance of hydrogen ion concentrations. pH adjusters are either of an acidic or alkaline nature, which will alter the pH level of a solution. When growing hydroponically pH is particularly important as the pH level of your nutrient solution will determine the availability of the elements. pH adjusters which are either acidic or alkaline, work simply by altering the pH of a solution; ie. If the chosen plant type requires pH 5.8 to 6.2 and the current pH is at 7.8 (slightly alkaline) a solution of acidic (pH Down) is added to lower the solution to the desired level. This also works in reverse. Use: Apply the relevant pH Adjuster (Up or Down) moderately, pour a little at a time in your water, mix well and verify the pH level. Repeat the process until the desired pH is achieved. Dosage will differ with the quality of your water.