Published 17 July, 2020

The rejection water of the reverse osmosis systems is a concern for those growers who use these systems to obtain the best water quality for irrigation and can present itself as an issue for large producers. When we need large amounts of reverse osmosis water, we must know that the amount of water discarded will be at least twice as much as the water produced by the osmosis system. This is why we wanted to publish an article talking about the rejection water of the reverse osmosis systems and the different methods to minimize it and also how to re-use this water.


The rejection water is the waste that comes out from the reject pipe (black color) and is sent to the drain when using a reverse osmosis system. Once the tap water has passed through the sediment and carbon filters, it enters the reverse osmosis membrane, which will purify a certain amount of water and send to the drain another amount of water with the dissolved salts that we want to remove. The rejection water is a clean, chlorine-free water but with an EC between 15-20% higher than that of tap water.


Flow restrictor 400 l/min

The amount of water rejected by a reverse osmosis system will depend directly on the flow restrictor installed by the manufacturer. Many reverse osmosis systems are designed to eliminate 4:1, 5:1, 6:1 or even more. This means that for every liter of water produced, 4, 5 or 6 times more water is needed and will be sent to the drain (or garden).

GrowMax Water reverse osmosis systems are designed to reject ONLY (2:1) two liters of water for every liter of purified water. This saves a lot of water!

The more water that is rejected will have a direct effect on the life of the reverse osmosis membrane. Smaller amount of rejected water can decrease the life of the membrane.


Diagram of a reverse osmosis membrane



But in addition, two more factors must be taken into account: The EC of tap water and the inlet water pressure of the reverse osmosis system.


Reverse osmosis systems remove up to 95% of salts and heavy metals from the water, i.e. depending on the EC of the tap water, so will be the quality of the purified water.

The life of the membrane will depend directly on the EC of the tap water. The higher the EC, the life of the membrane will decrease due to the amount of salts retained. Although the positive part of this is that we will reject the minimum water quantity as possible.


The inlet water pressure on a Mega Grow 1000 system

Reverse osmosis membrane manufacturers recommend a minimum pressure of 4,3 Kg/cm2 (BAR) for the membrane to work in good condition. Therefore, water production will increase or decrease depending on the pressure of water entering the membrane. Insufficient water pressure will cause the system to produce less water while increasing water rejection. If we have a lower inlet water pressure than recommended, we will must to install a Pressure Pump Kit for the system to work in optimal conditions.


As mentioned above, the rejection water contains a higher amount of salts than the tap water. We have also commented that the reject water is sediment and chlorine-free, which will allow us to use it for other purposes. For example, by accumulating the rejection water in a tank we can use it to clean the growing rooms and cabinets, trays, pots, tools, etc. In addition, we can also use it for scrubbing floors or for water for washing up. We can also send the water to the garden, for irrigation of trees or plants that do not need a low EC water. Finally, for all those who have a swimming pool, do not hesitate to fill it with the rejection water generated by reverse osmosis system.

Published 1 June, 2020

The acid pH in the water is usually a very common problem for most of growers. Since although pH 7 is considered neutral (neither acid nor alkaline), it is not the optimal pH for irrigation waters in indoor or outdoor crops. The recommended pH range of irrigation water for cultivation depends on the variety to be planted. In general, the correct pH for irrigation ranges from 5.2 to 6.8. If the pH of your water is higher, then you may need to treated it before using it in the crop. pH is the measure of the hydrogen ion concentration of a solution (how acidic or alkaline it is) and varies from 0 (the most acidic value) to 14 (the alkaline value). In most places the tap water contains substantial amounts of calcium (Ca) that gives it its characteristic hardness. These calcium levels can cause several problems, which can be relieved by performing some kind of pre-treatment of water.


There are several methods to soften the water and the safest is by using a reverse osmosis system, which completely eliminates calcium and bicarbonate. For horticulture, calcium bicarbonate is best neutralized by adding small amounts of concentrated acid to the water. Reverse osmosis neither changes nor alters the pH, this will remain the same although, it will lower the EC eliminating most sediments and above all, removing chlorine from the water.


  • The availability of micronutrients such as iron (Fe), manganese (Mn), zinc (Zn), copper (Cu) and boron (B), and plant growth, can be drastically reduced using an acid pH value.
  • An acid pH in the water can cause that the salts that fertilizers contain and that are used to fill the storage tanks, precipitate (crystalyze)
  • Water with an acid pH can also reduce the effectiveness of insecticides. Since most of them keep their properties active for longer in solutions with a low pH.
  • Much of the available calcium does so in the form of calcium bicarbonate, which can be precipitated both at the bottom of the tanks, different parts of the plant (trunk, roots, foliage), different tools (pots, trays, scissors) and accessories (humidifiers).
  • A continuous use of hard water for irrigation can also lead to a build-up of lime in the substrate. This is a problem of many long-season greenhouses where the accumulation of irrigation, leads to a high pH accumulation in the soil.
  • Many species of nurseries are sensitive to lime and pH accumulation in the soil and can be very harmful.
  • Using acid water in humidifiers can cause a white layer to appear on the leaf surfaces, reducing photosynthesis.
  • It is also very typical to block pipes and nozzles in automatic and hydroponic irrigation systems.


Alkalinity is the ability of water to neutralize acids. Dissolved bicarbonates such as calcium bicarbonate, sodium bicarbonate and magnesium bicarbonate, along with carbonates such as calcium carbonate, are the main contributors to alkalinity in irrigation water. Most laboratories assume that total carbonates (TC) are equal to alkalinity, but in fact in most waters, bicarbonates account for more than 90% of all alkalinity present. To be sure, it is best to perform a water analysis and see if the total of carbonates that are displayed in percentages or in number figures for each element.


Adding the right amount of acid will reduce the pH of the water. If you’re in an area with hard water and decide to acidify the water, you may need to decrease the amount of calcium in your crop mix to match the new alkalinity levels. If your pH drops, you may need to increase your calcium content.

Concentrated nitric acid (60%) also provides some nitrogen (N). For every 100 ml of concentrated nitric acid added to 1.000 l of water, 22 mg/l of nitrogen is being supplied. From a series of hard water samples analyzed, it was found that the amount of acid required varies between 50 ml and 200 ml of concentrated nitric acid per 1.000 l of water supply.

Therefore, it is essential to accurately assess the amount of acid needed in each case. If a small amount of acid is added above what is required, the pH of the water will become very acidic. The amount of acid required is best evaluated by the evaluation process. Using the graph as an example, a water sample containing 100mg/l of calcium requires 275 ml of concentrated nitric acid to bring pH to 5.9.


Apart from citric acid, some acids used for water acidification also supply nutrients in combination with hydrogen. The nutrients supplied may be beneficial for plant growth (whenever it is not realized in excess) but it also can react with the salts contained in fertilizers with a high concentration or with pesticides, if they are mixed in spray solutions.

Also, you’ll need to adjust the nutrient plan if your water is being acidified. For example, if phosphoric acid is to be used, reduce phosphorus (P) levels. If the result is a very high alkalinity in the water, it is not feasible to acidify with phosphoric acid.

If you use nitric acid, consider the additional nitrogen supplied from the acid. The use of nitric acid (67%) to acidify a water containing 6,0 mS/l of alkalinity would supply 67mg/l of nitrogen in each irrigation.

Citric acid is ideal as an acidifier for nutrient solutions and pesticide solutions because it is much less likely to react with salts or pesticides than the other three acids. Although is much safer to use, its cost may make it less desirable for large growing surfaces.


Concentrated acids are dangerous chemicals and should always be handled with care. Staff who work with them must be adequately trained, have all the necessary personal protective equipment and work ideally in pairs. Respirators and facial masks are recommended as fumes and vapor can be a real health hazard. Acid manufacturers provide on labels the safety data sheets for their products. Therefore, people who will use it should become familiar with the details of each and everyone of them.

Always add acid to water, not water to acid. Acidified water is corrosive and can devour the metal components of your irrigation system in the blink of an eye.

Published 18 May, 2020

Water is vital for plant nutrition, especially in cannabis plants as it participates in photosynthesis, helps maintain the internal temperature of the plant and most importantly: it transports all the nutrients present in the soil to the roots so that the plant can absorb the food it needs. Therefore, the type of water we use significantly affects plant nutrition and as such, we must make sure to water using the highest quality water possible. This is especially valuable when we want to produce large buds rich in THC (and/or CBD).

Currently, most growers water plants with tap water, but do you know that it contains different substances and unwanted elements? Do you know what they are? And the essential thing: Do you know how to eliminate them?


To begin with, tap water contains, in greater or lesser amount, CHLORINE. Chlorine is a man-added chemical and is used primarily to kill bacteria, fungi, parasites and viruses from drinking water. In addition, during the hottest season chlorine levels are increased to prevent the proliferation of these microorganisms.
In addition to chlorine, water contains other dissolved substances such as mineral salts and HEAVY METALS. The term “heavy metals” refers to a set of metals that, without being essential, have a toxic effect on living beings.
Elements such as cadmium (Cd), mercury (Hg), arsenic (As), copper (Cu), cobalt (Co) and lead (Pb), among others, can accumulate in the plant and pass to humans through consumption.


There are different qualities of water, depending on the concentration of mineral salts it contains: soft and hard. Its classification is based on the concentration of minerals they contain and the unit of measure for this purpose is: 
1 mg of contaminant/l = 1 ppm.
It is defined as hard water that which has a high content of dissolved minerals. Mainly, it contains a high content of calcium and magnesium. To measure its hardness, we observed how many milligrams of calcium salts are in a liter of water.
The range between 200 and 400 mg/l is the given range for hard water while between 400 and 550 mg/l is for very hard water. In general, tap water usually ranges from 170-400 mg/l. While not dangerous to humans, consuming this type of water is harmful to cannabis plants.
On the other side, soft water contains very few minerals. According to the water hardness scale, less than 150 mg/l is very soft water, while between 150 and 200 mg/l is simply soft water.


Let’s say that an Indica variety, can support EC levels between 1.4 and 2.2 mS/cm, depending on the development phase. If we provide a water with 1.0 mS/cm of EC, the amount of nutrients that we can give to our plants will be between 0.4 to 1.2 mS/cm (the difference) to reach the desired levels. Instead, if we provide a water with low EC levels, the amount of nutrients that we can give to our plants will be much higher: starting from a pure base water, the plants will not absorb any unwanted elements, so we will increase to 100% the efficiency of the nutrients and fertilizers that we use; we will know at all times the amounts of what and how much plants eat, as well as help stabilize the pH.
So, now that you know what type of water exists and what’s in your irrigation water, you can now add a water treatment system to your set up. Depending on the quality of your water you only have to choose the system that best suits your needs:




If you want to know the 10 REASONS TO LOWER THE EC AND REMOVE THE CHLORINE FROM WATER, click here.

Read the Spanish version


Published 12 May, 2020

Micronutrient management in plants is well known to the most experienced growers. Because although they are not needed in high doses, they help your plants achieve better performance. New growers, on the other hand, often overlook all the micronutrients their plants require to grow.

Plants need, in addition to NPK macronutrients (nitrogen, phosphorus and potassium), micronutrients in order to provide them with sufficient food. Finding the perfect balance between macronutrients and micronutrients in the soil will help you get healthier and more vigorous plants.

Nutrient categories

There are three different nutrient categories: primary nutrients, well-known macronutrients, or NPK (*did you know that water and air are also macronutrients?), secondary nutrients (those that plants need in smaller quantities) and micronutrients (those that are still needed in less than secondary ones). Among them they form the ideal diet of plants. And they are not even less important in the different phases.

If we think it and apply logic, it does not differ much from the ideal diet type for humans. Right?

*Water and air provide the necessary Carbon (C), Hydrogen (H) and Oxygen (O) throughout the plant cycle.

Secondary nutrients

Secondary plant nutrients are calcium (Ca), magnesium (Mg) and sulfur (S). These elements, although not needed in such high quantities, are necessary for good plant health. Sulfur helps develop vitamins, helps seed production and is an integral part of amino acid formation. Magnesium is a key component in the production of chlorophyll and helps plants use phosphorus and iron. However, in cannabis plants calcium plays an extremely important role.

Micronutrients reduction

Over the course of days and irrigation, it is normal for the arrangement of micronutrients in the soil to decrease, even following a specific fertilizer program. For example, in cases of high yield crops, where there is usually more time than normal in the growth and vegetation phases.

Another reason is that some fertilizers, such as NPK, contain lower or non-existent amounts of micronutrients as they focus on nitrogen, phosphorus and potassium macronutrients. Also, we can meet it in case of not arranging a fertile or quality soil.

Identification and functions

Each of the nutritional elements required for plants performs several functions. There are even some that help plants to properly absorb others of these elements. Since it is the case with hydrogen (H), which needs oxygen (O) from water and carbon (C) from the air to provide the basic components for plants to produce carbohydrates.


Iron (Fe) is an essential micronutrient for healthy plant growth. It is used by various enzymes and proteins during photosynthesis for the manufacture of chlorophyll. It helps with lignin formation, energy transfer and nitrogen reduction and fixation. It is responsible for the function, structure and maintenance of chloroplasts (components of plant cells and algae).

It also plays an important role in the breathing process, an essential function of life. Actively encouraging the production of chlorophyll and preventing leaf discoloration commonly found in dying leaves.


Boron (B) plays a very important role in bringing stability to plants. It helps cell membranes with their development, reinforcing their structure and is vital to regulate a plant’s metabolism. It is extremely important for plant growth, directly involved in germination, pollen formation and flower retention. Low boron plants can show hollow fruits and stems, as well as weak leaves.


Copper (Cu) activates some enzymes in plants involved in lignin synthesis and is essential in various enzyme systems. It is also required in the process of photosynthesis, is essential in the breathing of plants and helps the metabolism of carbohydrates and proteins in plants. In addition, it also serves to intensify the flavor and color in the vegetables and the color in the flowers.


Zinc (Zn) mainly helps to produce chlorophyll. Without zinc, the growth of plants is atrophy and the leaves are discolored due to zinc deficiency. This discoloration is called chlorosis, which causes tissues between the veins to turn yellow while the veins remain green, which usually affects the bottom of the leaf near the stem. 


Manganese (Mn) is a metallic element and one of the 13 natural minerals in the soil. It is the backbone of the photosynthesis process and is the reason why the leaves have their green color. Chlorophyll cannot capture the energy of sunlight for manganese-free photosynthesis. Soils rich in organic matter are also richer in manganese, but manganese can leach from lighter soils such as sand. Soils rich in organic matter are also richer in manganese, but manganese can leach from lighter soils such as sand. For this reason, manganese deficiencies are often quite common in light soils or with limited organic matter.


Nickel (Ni) helps the conversion of urea in plants, as it is a vital component of the enzyme urease. It is also believed to help with nitrogen fixation. To obtain a complete fertilizer for your plants, it may be helpful to choose one that includes nickel.


Chlorine (Cl) is a valuable plant micronutrient that helps with photosynthesis and the way plants use energy. More than chlorine, the plants that they use are chlorides that come from the chlorine that is present in the salt of the soil. Keep in mind that chlorine is very harmful to plants, so to be able to absorb it, they must be in a chloride compound.

And remember, to get the most out of your fertilizers (primary, secondary and micronutrients) in your crop, it is important to take into account the quality of the water. If we do not have a good quality inlet water, it is highly advisable (if not mandatory) to use a water treatment system. Available options are: Filtration Systems (REMOVE THE CHLORINE) or Reverse Osmosis Systems (LOWER THE EC).

Should I use a UV lamp in my irrigation system?  
Published 17 April, 2020

All those chlorine-free waters (wells, ditches, reservoirs, etc …) are susceptible to accumulating unwanted substances for irrigation: viruses, bacteria, herbicides, pesticides… Therefore, one of the questions that most concerns growers who use these types of water, it is whether they should use a UV lamp to sterilize the water, or not.

When we grow, we have several obvious reasons to maintain a pathogen and unwanted bacteria free setup. And the best way to do this is to start with a purified base water, using a Reverse Osmosis System. But there are some cases where it is necessary to add a UV lamp as a sterilizer.

In the case of using a Reverse Osmosis system or a Filtration System, it is necessary to install the UV lamp in the irrigation circuit, before these, to kill 99.99% of viruses and bacteria, thus sterilizing water. Furthermore, by installing the UV lamp before our water treatment system, we will lengthen and protect the life of the systems filters.

Ultraviolet radiation

Ultraviolet radiation or UV radiation is an electromagnetic radiation whose wavelength is approximately between 10 nm and 400 nm. Its name comes from the fact that its range starts from shorter wavelengths than what humans identify as the violet color. But this light, or wavelength, is invisible to the human eye as it is above the visible spectrum. This radiation is an integral part of the sun’s rays and produces several health effects because is between an ionizing and non-ionizing radiation.

Types of UV radiation

There are 3 types of ultraviolet radiation, according to their wavelength:

UVA: UVA radiation is the least harmful and the one that reaches Earth the most (95%), but overexposure is also harmful. Almost all UVA rays pass through the ozone layer. It is responsible for the immediate tanning of the skin. In the long term it also favors skin aging and the development of skin cancer. It is between 320 and 400 nm.

UVB: It is biologically very active but the ozone layer absorbs most of the UVB rays from the sun. However, the current deterioration of the layer increases the threat of this type of radiation. As short-term effects, it is responsible for burns and delayed tanning. In the long term, it favors skin aging and the development of skin cancer. It is between 290 and 320 nm.

UVC: It is the most harmful due to its great energy. Fortunately, oxygen and ozone in the stratosphere absorb all UVC rays, so they never reach Earth’s surface. It is between 100 and 290 nanometers.

How does a UV sterilizing lamp work?

The key factor for effective operation of a UV sterilizing lamp lies in the wavelength of the light it emits: UV-C light. With a short and powerful wavelength, it destroys nucleic acids in the DNA of a pathogen. Eliminating their ability to infect, reproduce, and perform vital cellular functions, making them harmless.

Its use is recommended in cases of using accumulation water tanks. Especially if they are exposed to the sun and the water remains stagnant for an amount of time. Even if you have used previously treated tap water, if that water will also remain stagnant for an extended period of time, there is a very high probability that unwanted pathogens will proliferate again. In both cases, the only way to ensure complete sterilization is to install the UV lamp after the accumulated water has been deposited, before the water enters the crop irrigation circuit.

For all the cases in which it is watered using a chlorine-free water, coming from wells, ditches, reservoirs or similar, GrowMax Water offers different Kits of UV sterilizing lamps: The UV Lamp Kit 4 LPM (with a flow of 4 L/min) and the UV Lamp Kit 22 LPM (with a flow of 22 L/min). Which include transformer, fittings and wall mount clips. Everything ready to install and use.

Published 18 February, 2020

pH is the Hydrogen potential of a liquid or dissolution. Its indication is given by a numeric value within a range of 0 to 14, remaining 7 (as a general rule, later we will go deep into this topic) as the given value for a neutral pH. Values with a pH less than 7 are acidic and values greater than pH 7 are alkaline.



I’m sure you’ve ever heard someone say, “the pH, but what is that?” or “meter of what?”, right?

pH is not one of the most exciting topics of growers, but all professionals know that pH must remain between values of 5.5-6.5 because certain elements can only be absorbed by plants in that range. It is therefore understandable that many novice growers can become a real headache.


Because pH is a logarithmic factor (it does not add up, it multiplies). When the pH decreases on 1 unit the solution becomes 10 times more acidic. When the pH decreases by 2 units the solution becomes 100 times more acidic.

Medidor digital de pH

The opposite happens if we increase by 1 unit, the solution becomes 10 times more alkaline and if we increase by 2 units, it becomes 100 times alkaline.

Therefore, the variation of only 1 unit in the pH value can have an unwanted impact on plants and become a real disaster.

As in this example, where the gardener did not want to vary pH levels during the different stages of the plant. It always kept the pH at 5.5 and the result, you can imagine…


If we want to be sure that our plants absorb the most elements and nutrients, the solution is to keep the water in the mixture with a neutral pH. Ideally, start with a pH of 5.5-5.8 in the growth phase and gradually increase it to 6-6.5 in the flowering phase.

To do this, it is advisable to have a good base water and the best method of achieving it is to start with a water that is as pure as possible. The best way to achieve this is through a Reverse Osmosis System as a pre-treatment of water. Which at the same time helps to stabilize the pH of the water.

If we use hydroponic irrigation systems or the like, we must also maintain pH levels in a consistent, stable way.


In addition to measurements in liquids and solutions, measurements can also be made on the skin of animals and humans*, fruits, vegetables, the soil of a crop itself, rainwater, well water, etc.

*The pH value of the skin ranges from 4.5 to 5.9 so the skin’s natural pH is slightly acidic and its optimal value is 5.5. In addition, the pH of the skin varies slightly depending on the age, gender and place of the body (genitals, hands and armpits).


When it comes to the pH in the irrigation water for our plants, we must take into account:

  • The PH of the water inlet.
  • The PH of the water once the fertilizers are added.


The water we use, normally from the tap, usually comes from the water treatment plants of large cities and towns. Therefore, it is treated with conventional chemicals to adjust an appropriate pH level. This appropriate pH level may vary depending on the time of year and above all, depending on the area in which you live. So, it is advisable that you find out what the initial pH is before mixing the fertilizers since in addition, surely this same water will come with high values of EC.


This is where problems usually come in. On the basis that not all fertilizers have the same pH and that some also have very high (or low) values, it is almost impossible that when mixing them, you acquire the appropriate pH if you do not use some measuring instrument and some regulator.



To control the pH there is no other option than to use a specific tool. To do this, we have different options such as test strips, drop kits or professional meters.

Tiras reactivas


The pH test strips are made of paper impregnated with a chemical that depending on the pH of the sample with which they make contact, changes to different colors.

Indicator paper strips are used both at the laboratory level and at the particular level, and are even used in clinical laboratories, especially for urine analysis.

Kit de gotas


PH test kits are very practical and economical. They contain a reagent to measure the pH of the irrigation water and a clear canish where the sample is measured by introducing your water from the growing broth and adding 2 drops of the reactive liquid.

Medidor digital de pH


There are different models of digital pH meters available on the market. With a wide range of prices, all valid and functional. There are also those that perform different functions as well as measure EC and temperature (so-called combos) on a constant basis, mandatory for use when using different hydroponic techniques. For a good use it is essential to follow the advice of each manufacturer for best maintenance.

Medidor de pH de suelo


There are other meters on the market to control the pH of the soil. Designed for direct use in the soil are an excellent solution to check the acidity of the substrate that we are going to use for a given crop. If you are one of those who reuses the substrate, this meter cannot be missing among your used tools.


pH regulators are another must-have tool that can’t be missing from your arsenal. They are usually composed of natural products and can be found in different formats such as powder or liquid. They are not very expensive and their efficiency time is almost immediate (some manufacturers claim that in less than 10 seconds).


Reguladores Reguladores


If you grow organic make sure that you do not acquire the minerals, it will negatively affect the maintenance of the beneficial microorganisms existing in the soil.

If we want to get quality harvests, a small reminder: controlling the pH of water is as important as controlling EC.


Published 2 January, 2020

Isn’t salt a bad thing for plants? As gardeners and growers, we are very aware of the damage caused by soil or excessively salty water. However, guess how long a plant could live without salt. The answer is not very long …

A plant can only absorb a nutrient when that nutrient is in the form of ionic salt. This is because there must be a membrane potential (positive versus negative) to provide energy and move the nutrient toward the cell cytoplasm.

Therefore, proper administration of nutrients is necessary for healthy plant growth. Knowing how these factors balance will greatly contribute to maintaining a healthy crop.


Let’s take a look to an organic nutrient; We will use nitrogen as an example. Plants need nitrogen to produce leaf growth (among other things), however, root systems can’t absorb nitrogen directly.

In chicken manure, approximately 80% of the nitrogen content is organic and must be mineralized or converted to ammonium or nitrate to be available for plant absorption. For some forms of nutrients, this process usually takes up to a year. Time, temperature and bacteria are required to perform the conversion.

This is the main reason why organic nutrient applications do not overfeed or burn a plant. The nutrient is simply not in a form that the roots absorb. It is after this conversion process that the nutrient becomes salt and is available for absorption.


Most of the nutrients found in organic fertilizers are not yet in salt form, so the plant cannot absorb them. So, is there any benefit to this? Yes.

Let’s see the nitrogen again. There are different processes to convert nitrogen sources into ionic salt, and these coincide with the basic types of fertilizers. The first of these processes is hydrolysis, where nitrogen is converted by water.

The second is mineralization, where the microbial action of the soil converts the nitrogen source. The temperature completes the mineralization process. The processes or reactions that must occur in order for nitrogen to be available to the plant is quite complex.

During the mineralization of an organic nitrogen, the bacteria, in particular with the protozoa, are put to work consuming the nitrogen and converting it into nitrates, ammonium and other by-products. These nitrates are immediately available to the plant. This process takes time and increases the temperature and goes slowly, so the availability of nitrates is gradual and safe.

After nitrogen, phosphorus also requires the same type of reactions to become a salt and, therefore, available for plant absorption. Plants mainly absorb phosphorus as primary and secondary orthophosphate ions with negative charge.

Some prepared nutrients may have these already within the fertilizer compound, while organic forms require that mineralization processes occur first. This again makes the release of nutrients slower.

Granulated salt


During the transformation of nitrogen, bacteria in the soil, such as nitrobacteria, along with a multitude of other bacteria and protozoa, feed continuously. As a result, microbes multiply and create a living soil.

The concentration of microbes in living soil can be amazing. A teaspoon of fertile soil can contain 100 million and even up to a billion bacteria. Up to more than 60 km of fungal filaments, or hyphae, can also be present in that small sample.

Living soil is the main basis for creating the vigor and health of plants to help growers obtain maximum yield on their crops. These microbes retain water in their cells that may be available to the plant later. Bacteria eat exudates from plants such as sugars, carbohydrates and applied organic nutrients.

The protozoa then excrete nutrients available to the plants. Beneficial fungi protect plant roots from pathogens and harmful microbes while forming a symbiotic relationship with the roots for greater nutrient absorption.

Mycorrhizae are an example of this. If you have ever used a soil impregnated with this beneficial fungus, you already know how much vigor, foliage, flower and additional fruit can be obtained from the plant.

In all cases, the mineralization process builds the life and health of the soil. The amount of benefits of living land is overwhelming, and this is the reason why many gardeners prefer to use organic nutrients.


When reading “nitrogen“, on the label of your fertilizer, you can see what percentage of the product is nitrate, ammonium nitrogen or urea soluble and insoluble in water.

Because many fertilizers use at least some, if not a large amount, of urea, it is useful to analyze this characteristic. Like organic forms of nitrogen, the mechanism of urea release is mineralization. Urea usually takes up to a month to be available to plants. However, there are several different types of urea and each has considerably different release times.

Cold water soluble urea becomes available to plants in a couple of weeks, while hot water soluble becomes available in 2 to 3 months, depending on soil temperature. Water-insoluble urea can take several years to release.

Because these nutrients can be available at such a variable rate, you can see why it is difficult to know if your crop is being fertilized in excess. Care must be taken and periodic soil tests can help you know if additional nutrients are needed. In addition, it is always better to read the label to know the assimilation characteristics of plant nutrients.


However, there are circumstances in which adding mineral nutrients ready for absorption to an organic nutrient base may have its advantages.

In cases where a plant shows signs of insufficient nutrition, sources of organic nutrients may be too slow to correct this deficiency in time to avoid a reduction in several desired crop characteristics. Adding the right amount of inorganic nutrients to the soil, or even a foliar application, may be the solution.

In many mineral fertilizers, the nutrients they contain can be absorbed immediately by the root system, or at least they will be available very quickly. For example, the form of nitrogen nitrate that is often provided in synthetic fertilizers is immediately available (which facilitates excessive fertilization of a plant).

While mineral nutrients do not sterilize the soil itself or feed the soil microbes, these microbes will still reproduce and do a good job as long as organic nutrients are present. It’s only when the producer depends solely on inorganic nutrients that the soil will gradually become sterile by starvation of the microbes.

Knowing the right amount and the right reason to add mineral nutrients is the key to success. In addition, during certain phases of growth, a stream of phosphorus or extra nitrogen can create several desired effects. Micronutrients, those that can add flavor, may also be necessary at a specific time during the growth and flowering cycles.


In the end, remember that using organic forms of nutrients will build the soil while feeding your plants. This should be a priority for any grower. So try to keep an open mind about the use of mineral nutritive salts (fertilizers) in situations where they can benefit your crop.

Published 2 December, 2019

The complexity, beauty and incredible diversity of orchids are unrivaled in the plant world. These exotic gems comprise the largest family of flowering plants on earth, with more than 30.000 different species and at least,  200.000 hybrids.

Within this large number of varieties and hybrids of orchids, there are many that are perfectly happy growing in the hollow of a sunny window or under artificial lights.

To obtain greater possibilities for success, choose one of the least demanding varieties that suits the type of growth conditions we can provide. Choose the most mature plant that the place has (young plants are much more difficult to please) and, if possible, choose one in bloom to know what we will strive for.


 Orchids can be classified by their native habitat, which gives an indication of the temperature, humidity and light levels they prefer. Orchids can be found in the equatorial tropics, the Arctic tundra and everywhere in between. The reason for this diversity lies in the incredible ability to adapt to its environment.

With so many different orchid varieties that thrive in so many different growing conditions, it is relatively easy to find an orchid that adapts well to the conditions we have.


Most cultivated orchids are native from the tropics. In their natural habitat, they adhere to the bark of trees or the surface of other plants. Its thick white roots are specially adapted to absorb moisture and dissolved nutrients. Because these tropical orchids generally grow in high places in the trees, instead of on the forest floor, they are accustomed to good air circulation and lot of light. They prefer a 12-hour day throughout the year and require a high intensity of light, almost the same as in summer conditions in temperate regions.

Native orchids in the humid tropics, such as phalaenopsis and paphiopedilum, prefer daytime temperatures of 20°C to 30°C, with 80 to 90 percent humidity. They are happier in a window located to east or southeast where the light is not too intense.


Warm-weather orchids, including cymbidiums and dendrobiums, are used to an average temperature of 13°C to 21°C, a constant supply of moisture and good air circulation. They are generally happy in a south-facing window, although they may need some shade during the summer.

Cattleyas and some oncides grow where the days are dry and relatively fresh. They are able to tolerate a long dry season with temperatures of 25°C or 32°C, followed by a different rainy season. Their need for light is high, so they should be placed in a sunny window facing south


High altitude orchids, such as masdevallia and the epidendrum, grow in cloud forests where average temperatures are 15°C to 20°C and humidity is very high. These orchids prefer filtered light, which is not too intense.


Orchids are usually grouped into two broad categories that characterize their growth habits: monopodial and sympodial.

Monopodial orchids have a single vertical stem, with leaves arranged opposite each other along the stem. The flower stem appears from the base of the upper leaves. Orchids with this growth habit include genera such as phalaenopsis, vandas and ascocentrum.

Sympodial orchids are the most common. Most of these orchids have pseudobulbs that function as reserves of water and nutrients. The plant supports the pseudobulbs almost vertically and the subsequent growth and development of new stems occurs horizontally, among the pre-existing pseudobulbs. Each new pseudobulb originates at the base of the previous ones and, with its growth, originates new leaves and roots. Some examples are those of the genera cattleya, cymbidium, oncidium and dendrobium.


All orchids need a lot of light to thrive, but nevertheless they do not support direct sunlight. The appropriate location can be near a window where it receives a lot of light, preferably with a curtain or blind. For those windows facing south or in the summer, which can enter direct sun, it is necessary to sift the light through curtains, blinds or canopies.

Another good practice may be to leave them in the shade of other larger indoor plants that withstand direct sunlight. Just as the direct sun is harmful, the lack of lighting is another big problem, which will limit the growth and flowering of the plant.

Some symptoms of not having the necessary light can be a growth of long, thin and yellowish leaves, which fall easily and cause the plant to not bloom. In these cases it is advisable to use artificial lighting.


The irrigation water quality in orchids is very important since they are extremely sensitive and delicate. A water with a high content of mineral salts will block the ability of the roots to absorb food, which is known as a nutrient lookout.

To avoid this problem we must use a quality water, free of mineral salts, which will lead us to discard the use of tap water, unless we have previously treated it with a reverse osmosis system. In this way, in addition to removing 100% of the mineral salts from the water we will also remove up to 99% of the chlorine.


Irrigation and humidity are two other key factors for proper maintenance (and survival) of our orchids. Starting from the base that not all orchid families have the same needs, we should try to find out beforehand to recreate them as much as possible in the location we choose.

Inadequate irrigation, such as excessive watering, can cause the orchids to kill, since their roots are very sensitive and tolerate the lack better than excess watering. In addition, since most of them come from tropical climates and grow on top of trees, without direct contact of the roots with the soil, they are used to extract water from the humidity of the surrounding environment.

If you want to dig deeper into the entire universe of orchids, you can visit this page where you will find much more information in a detailed and specific way according to gender, habitat and habits.