Calcium and Boron have a close relationship in the plant.  Their absolute concentrations and the relative ratio between the two affects how much of each can be absorbed. Both play an important role in growth points, or rather meristematic tissue. Although both these nutrients are not problematic in most crops, it is good to know [...]

Green bean fertigation must be controlled carefully since they are extremely fast growing. There are pro's and con's of fast growing crops.  An advantage can be that any deficiency or toxicity can be outgrown quickly.  The disadvantage is that the crop can develop one of these physiological disorders very quickly. The speed at which green [...]

Tomato fertigation is a complex subject in hydroponics.  It is climate sensitive and everybody has an opinion of what works. The point is, tomatoes are sensitive to water stress (too little water) and to water logging (over watering). They are not as sensitive as peppers or cucumbers. Water stress or water logging will reduce plant [...]

Fertigation of peppers is sometimes more of an art than science since plant requirements change as the weather/climate change. Learn how to read your plants and identify good and bad stress symptoms. Peppers are sensitive to water stress (to little water) and to water logging (over watering). Any of these two conditions will reduce plant [...]

Great care should be taken when working with chemicals. It is important to adhere to the following guidelines, which can be applied to all types of chemicals: Always keep the same type of chemical together. Always close the containers properly. Never leave any container open so that the gasses can escape. Place a brick or [...]

Most automated systems installed in closed hydroponic systems use injectors rather than proportioners. A simplified diagram of where to install such a system is provided below. Many advanced injectors such as the Priva® and Volmatic® systems use much more complex configurations. Most of the systems use two pH probes and two EC probes in case [...]

To make a nutrient stock solution, you need a minimum of two tanks. Nutrient Stock solutions cannot be made in one tank. The reason is that above a certain concentration, calcium reacts with sulphates and phosphates to form insoluble calcium sulphate ([latex]\ce{CaSO4}[/latex]) and calcium phosphate ([latex]\ce{Ca3(PO4)2}[/latex]). The two nutrient tanks will be called Tank A and [...]

Fertilizer solubility is one of the key elements in making hydroponic nutrient stock solutions.  If you know the fertilizer solubility, you can make optimum stock solutions for any size nutrient tank. Making stock solutions is extremely simple. All you have to do is to calculate the amount of fertilizers required to make a normal 1:1 [...]

Micro nutrients are just as important as macro nutrients. Many growers fail to have their water analysed for all elements, and in some area one might have enough of a micro element in the water. By adding more with fertilizers, toxicity levels may be reached which can reduce yields significantly. The following example will use [...]

Not all fertilizers are pure. Some have impurities, such as clay, silt and sand particles, also called “carriers”, that do not provide any nutrients to the plant. After calculating the amount of fertilizers that needs to be added to a nutrient tank, the weight of the impurities should be taken into account and subtracted from [...]

Liquid fertilizers are treated slightly different than granular fertilizers. They do not have impurities, but their density or specific gravity need to be taken into account. In most calculations, it is assumed that fertilizers are granular, so we use the weight of the fertilizers. If it is a liquid, we would have used volumes such [...]

Formulating one’s own nutrient solution should be left to advanced growers. Any mistake could lead to the loss of the whole crop, unless the mistake can be identified early, in which case the nutrient solution in the tank is lost. The hypothetical example will be used to show how to calculate the amount of [...]

Stock solutions are essential component of any hydroponic farm.  Imagine a system, 5,000 m² in size growing tomatoes. The estimated number of plants would be 15,000. On average tomato plants consume 1.5 – 2 L of water per day. The system would require at least 30,000 L water per day. If a grower has one [...]

The grower has the option to obtain pre-mixed fertilizers that are already mixed in the right ratio for a specific crop or to use basic fertilizers and to mix them into various tanks and ad them to the fertigation system. The first option is the easiest but slightly more expensive and recommended for inexperienced growers. [...]

The amount of nutrients in a solution is expressed as a concentration. For instance; if 1 g of potassium sulphate is added to 1,000 L of water, one could express the amount of potassium sulphate in relation to the amount of water as 1 g.1000 L-1 potassium sulphate solution (it can also be expressed as [...]

The atomic weight or molecular weight is the relative weight of each atom compared to other atoms. The base element to which all other elements are measured is oxygen and it is given the value of 16.00. The atomic or molecular weights of the most important elements used in hydroponics are provided below. The values [...]

First it is important to understand which nutrients are included in the various fertilizers and in what amounts. It is important to distinguish between macro and micro elements. The macro elements are taken up in large quantities and the micro elements in smaller quantities. Although the micro elements are taken up by smaller amounts, it [...]

Plants consist of 80-95 % of water, depending on specie, less than 15-20 % percent consists of carbon (C), oxygen (O) and hydrogen (H). The remaining 1.5 % is made up of the macro and microelements. This small portion will be our focus. All plants require macro- and microelements in specific ratios in order to grow properly. The soil [...]

What is pH pH is the measurement of acidity or alkalinity of a solution. It is based on a logarithmic scale and starts at 0 and ends at 14 where the value 7 indicates a neutral, neither acid or alkaline. If a solution has a pH value below 7 it is called an acid. If [...]

Nutrient removal is quite often neglected in closed hydroponic systems since it is difficult to measure and control.  The reason is that not all nutrients are removed at an equal rate by plant roots. The essential nutrients can be grouped into 3 categories based on the rate of uptake from the nutrient solution. Elements are actively [...]

Refilling nutrient solutions are only required when a closed (NFT) system is used. With open hydroponic systems the nutrient solution is not re-used so no refill solution is required. Very little information is available on the subject and methods should be developed according to system design. Each system will have unique requirements because of factors such as: plant growth [...]

The following procedure should be followed when mixing fertilizers in nutrient tanks: Fill the tank with water Check if the pH is between 5.5 and 6.8 Increase or decrease the pH if necessary with either an acid or base Start stirring the water in the tank. The water in the tank can also be agitated [...]