General characteristics
convention is defined as one growing in gravel hydroponic system that includes methods in which plants grow on a substrate, usually non-absorbent, and whose particles are between 2 mm and 2 cm in diameter.
Among the many materials that are considered serious and are often used in hydroponics are the following: basalt, granite, volcanic rock, pumice, brick pieces, charcoal, polystyrene, polyurethane, rice bran, etc. .
The nutrient solution was supplied almost exclusively by subirrigation, ie, the solution is applied to the bottom of the tub or container and is wetting the gravel from the bottom up.
This chapter discusses different methods under the generic name growing in gravel and only particularized in different substrates when methodological differences or economic consideration.
gravel cropping requires the use of waterproof tubs. As a substrate for the roots are put into tubs half, generally non-absorbent, with relatively large particles to ensure good aeration (> 2 mm in diameter), but not so large that do not retain sufficient moisture for roots. As soon as the solution is forced into the tub and runs from bottom to top, the carbon dioxide radical product of respiration, is removed from the gravel, by draining the solution quickly, sucking fresh air substrate, which is exploited by the roots growing plants. Gravel particles retained on their surfaces (and also within the porous particles) enough moisture to allow good growth.
The solution can be reused indefinitely (if you make frequent chemical analysis and restores the water lost through transpiration) or renewed periodically.
Depending on their size and other characteristics, gravel particles begin to dry after a few hours and need to be watered often enough so that commercial level requires a very efficient pumping equipment.
gravel cropping has shown several advantages in commercial installations and is the most commonly used in hydroponic facilities in the United States and Israel.
Technical Problems
gravel hydroponic cultivation presents some technical problems of considerable importance.
Nutritional characteristics: in general, the nutritional management is similar to that under cultivation is performed in solution and is exact under cultivation in the aggregate.
Under this section discusses three aspects of the solution acidity, level of phosphates and iron level.
acidity of the solution to achieve the best results should remain the acidity of the solution within the range that goes from medium to slightly acid. Acidity fluctuations are not as marked as under cultivation in solution, but much more than in aggregate culture.
phosphate level: the level of phosphates in the nutrient solution should be properly regulated. Excessive amounts of this radical leads to precipitation of trace elements in it (mainly iron). It is recommended, therefore, not exceed six millimoles phosphate concentration.
Proper management of the level of phosphate favors the regulation of the acidity of the solution due to its stabilizing action. A merger between two and four millimoles favors that action.
iron level, one of the main problems in gravel culture is to maintain an adequate level of iron in the nutrient solution.
Although often is enough iron in the water and impurities of commercial fertilizer to meet plant demand, frequent additions are recommended in small concentrations.
Excess iron can cause a deficiency of phosphorus, so the additions should be about one part per million (ppm).
physical characteristics: the main issues relating to the physical characteristics of the crop in gravel include: type and characteristics of the gravel, aeration, drainage requirements, irrigation frequency, volume of solution, washed gravel and gravel temperature .
type and characteristic of gravel: there is, as already mentioned, a variety of substrates conventionally called horn gravel. Each has certain features, benefits some and disadvantages others, to be taken into account when selecting them. To achieve a satisfactory growth of plants, the gravel must have several characteristics desirable as those listed below:
1. Not contain toxic materials. In some types of coal can be found excessive amounts of boron or sulfur compounds, so it is recommended to thoroughly wash and / or treated with a solution of sodium silicate.
The most common problem is, however, excessive acidity or alkalinity of the substrate, whether caused by foreign substances or because the type of gravel is so by nature. To correct the alkalinity can be washed thoroughly with water the substrate with an acid solution or a solution of superphosphate. In case of excessive acidity (rare situation in practice) suggested washing with water, a potassium hydroxide solution or a solution of superphosphate.
2. The media should promote excellent drainage. The size of the particles, the presence of foreign material such as sand, soil or mud and gravel porosity are the main factors related to this feature. All free liquids must be drained, only a thin film of moisture (and nutrients) should be retained on the surface of the particles.
3. The gravel should provide good moisture retention. The main factor involved is the size of the particles influences also the fact that irregular particles flat or have larger contact surfaces, which allowed greater retention of moisture. The porosity is also important, however, presents some problems, for example, porous gravels are difficult to clean and therefore it is almost impossible to remove impurities and nutrients that may even reach levels of toxicity, for the same reason chemical sterilization can see a bit more difficult.
4. Should facilitate adequate aeration. This feature is related to moisture retention and drainage.
5. The gravel must be of sufficient consistency to be durable. Some types of gravel are soft and will decompose over time difficult drainage and, consequently, adequate ventilation.
6. The gravel should not have sharp edges. Some types of gravel are sharp and can cause mechanical damage to some plants especially where the wind is strong.
More info ...
convention is defined as one growing in gravel hydroponic system that includes methods in which plants grow on a substrate, usually non-absorbent, and whose particles are between 2 mm and 2 cm in diameter.
Among the many materials that are considered serious and are often used in hydroponics are the following: basalt, granite, volcanic rock, pumice, brick pieces, charcoal, polystyrene, polyurethane, rice bran, etc. .
The nutrient solution was supplied almost exclusively by subirrigation, ie, the solution is applied to the bottom of the tub or container and is wetting the gravel from the bottom up.
This chapter discusses different methods under the generic name growing in gravel and only particularized in different substrates when methodological differences or economic consideration.
gravel cropping requires the use of waterproof tubs. As a substrate for the roots are put into tubs half, generally non-absorbent, with relatively large particles to ensure good aeration (> 2 mm in diameter), but not so large that do not retain sufficient moisture for roots. As soon as the solution is forced into the tub and runs from bottom to top, the carbon dioxide radical product of respiration, is removed from the gravel, by draining the solution quickly, sucking fresh air substrate, which is exploited by the roots growing plants. Gravel particles retained on their surfaces (and also within the porous particles) enough moisture to allow good growth.
The solution can be reused indefinitely (if you make frequent chemical analysis and restores the water lost through transpiration) or renewed periodically.
Depending on their size and other characteristics, gravel particles begin to dry after a few hours and need to be watered often enough so that commercial level requires a very efficient pumping equipment.
gravel cropping has shown several advantages in commercial installations and is the most commonly used in hydroponic facilities in the United States and Israel.
Technical Problems
gravel hydroponic cultivation presents some technical problems of considerable importance.
Nutritional characteristics: in general, the nutritional management is similar to that under cultivation is performed in solution and is exact under cultivation in the aggregate.
Under this section discusses three aspects of the solution acidity, level of phosphates and iron level.
acidity of the solution to achieve the best results should remain the acidity of the solution within the range that goes from medium to slightly acid. Acidity fluctuations are not as marked as under cultivation in solution, but much more than in aggregate culture.
phosphate level: the level of phosphates in the nutrient solution should be properly regulated. Excessive amounts of this radical leads to precipitation of trace elements in it (mainly iron). It is recommended, therefore, not exceed six millimoles phosphate concentration.
Proper management of the level of phosphate favors the regulation of the acidity of the solution due to its stabilizing action. A merger between two and four millimoles favors that action.
iron level, one of the main problems in gravel culture is to maintain an adequate level of iron in the nutrient solution.
Although often is enough iron in the water and impurities of commercial fertilizer to meet plant demand, frequent additions are recommended in small concentrations.
Excess iron can cause a deficiency of phosphorus, so the additions should be about one part per million (ppm).
physical characteristics: the main issues relating to the physical characteristics of the crop in gravel include: type and characteristics of the gravel, aeration, drainage requirements, irrigation frequency, volume of solution, washed gravel and gravel temperature .
type and characteristic of gravel: there is, as already mentioned, a variety of substrates conventionally called horn gravel. Each has certain features, benefits some and disadvantages others, to be taken into account when selecting them. To achieve a satisfactory growth of plants, the gravel must have several characteristics desirable as those listed below:
1. Not contain toxic materials. In some types of coal can be found excessive amounts of boron or sulfur compounds, so it is recommended to thoroughly wash and / or treated with a solution of sodium silicate.
The most common problem is, however, excessive acidity or alkalinity of the substrate, whether caused by foreign substances or because the type of gravel is so by nature. To correct the alkalinity can be washed thoroughly with water the substrate with an acid solution or a solution of superphosphate. In case of excessive acidity (rare situation in practice) suggested washing with water, a potassium hydroxide solution or a solution of superphosphate.
2. The media should promote excellent drainage. The size of the particles, the presence of foreign material such as sand, soil or mud and gravel porosity are the main factors related to this feature. All free liquids must be drained, only a thin film of moisture (and nutrients) should be retained on the surface of the particles.
3. The gravel should provide good moisture retention. The main factor involved is the size of the particles influences also the fact that irregular particles flat or have larger contact surfaces, which allowed greater retention of moisture. The porosity is also important, however, presents some problems, for example, porous gravels are difficult to clean and therefore it is almost impossible to remove impurities and nutrients that may even reach levels of toxicity, for the same reason chemical sterilization can see a bit more difficult.
4. Should facilitate adequate aeration. This feature is related to moisture retention and drainage.
5. The gravel must be of sufficient consistency to be durable. Some types of gravel are soft and will decompose over time difficult drainage and, consequently, adequate ventilation.
6. The gravel should not have sharp edges. Some types of gravel are sharp and can cause mechanical damage to some plants especially where the wind is strong.
More info ...
