Home / Gardening Guides / Ebb and Flow Hydroponic System – How Does It Work?

Ebb and Flow Hydroponic System – How Does It Work?

In a hydroponic medium, the plants get a complete nutrient formula and an inert growing medium to anchor the plant’s roots to have easier access to food and water.

There are six different kinds of this gardening method, where the three necessities comprise water(moisture), nutrients (food), and oxygen. The most prevalent is Ebb and Flow, also known as flood and drain system.

The working of the Ebb and Flow system is an enigma to many. Indeed, because it is hard to set up initially, it is not selcouth like any other hydroponics method and will be fun and effortless to maintain.

The postulates of Ebb and Flow adapt the same water as the essential nutrient with one distinct improvement. Instead of watering the plants from up, it gets water from the bottom-up (reverse from the general farming methods).

This is to prevent the growing medium from getting wet. The Ebb and Flow system work in the manner of temporarily flooding the grow tray with the dissolved nutrients and momentarily draining it back to the reservoir.

This takes place with the help of a pump (generally connected to a timer). When the grow tray gets flooded with a nutrient medium, the timer (or manually) shuts the pump off, and the medium flows back into the reservoir.

The type of plant, temperature, humidity, and the genus of growing medium used; decided the number of times the grow tray shall be flooded and then drained subsequently.

1. The Inns of Ebb and Flow:

The rooting media:

For rooting medium, the Ebb and Flow systems plants get rooted in an inorganic substrate with the nutrient suspension applied by periodically flooding the rooting media.

For example, the physical and chemical properties of one inorganic substrate, Stonewool. To start with, it is clean and non-toxic but may give skin irritation, reusable, and sterile.

It has a high holding water capacity of up to 78% and provides about 17-18% ventilation (air-holding) capacity. This makes it ideal for seed generation and generally preferred for long-term plants.

The elemental content in a rooting medium is a significant factor and affects the plant’s nutritional status. Initially comprehending what the actual rooting media content is, and can match it with an appropriate fertilizer (nutrient solution) formulation in progression to dodge the potential of a plant nutrient insufficiency.

The nutrient solution:

The nutrient solution is the most misunderstood of Ebb and Flow systems, mainly because there is insufficient information about this.

The precise measurements of aliquots of the solution and the necessary weights are essential in the whole setup. Indeed, there are no free pat prescriptions that will work and show definite results.

Over time, growers experiment with their systems, observing, testing, and adjusting until the proper balance between composition and used for their particular situation and specific plant species opted.

The most suitable nutrient solution depends on the foremost— the frequency and rate of nutrient solution dozing of plant roots; and the second—the plant nutrient element requirements.

The Quality of Water:

A critical thing to contemplate is the WATER QUALITY, as this has the most effects on the healthy working of the Ebb and Flow systems.

Even the best domestic water comprises substances and factors that can affect the growth—the thorough analysis of the water to be used for the Ebb and Flow system is an essential element that affects the working.

The water supplies can contain sizable concentrations of essential elements required by plants, mainly Calcium and Magnesium. The surface (or) the pond water may contain disease organisms such as algae, posing problems. Any form of water treatment is necessary, depending on what exists in the water supply.

The water treatment is done only if the chemical and physical composition of the water warrants greater extents. Financial and managerial planning must be in accordance to incorporate the costs of producing nutrient-pure water depending on the various factors mentioned and the conditions from which the water— taken initially.

Let us say, for example, that it is financially prudent to accept some amount of plant loss from the use of detrimental water rather than venturing to recover the cost of water operation. The treatment may be as inexpensive and straightforward as acidifying the water.

Ebb and Flow Hydroponic System

2. The outs of Ebb and Flow:

Watertight rooting bed (plant tray):

The plant tray used in Ebb and Flow is also known as grow-tray (or) flood-tray. It is a large shallow tank (preferable size ranges from 6 to 8 inches) placed on a tall stand where the plants are grown. The whole of the plant tray gets covered with a growing medium.

The rooting bed(pots):

The pots are double the size of the plant tray. As mentioned, the plant tray itself can occupy the entire growing medium. Still, individual containers are preferred, making it more comfortable to move the plants, sometimes in or out of the system.

The nutrient solution sump(Reservoir):

The reservoir is placed directly below the flood tray’s stand—can be placed nearby but preferred because gravity does most of the work, which is connected to the plant tray via the drain and fill tubes.

The fill hose is attached to a submersible pump (preferred with timer), which regulates water flow in the system. The drain hose serves to drain the water from the plant tray after flooding the plants; this so the water can be used reused.

3. The overall operation of Ebb and Flow:

The science of plant nutrients has attracted considerable attention, and the characteristics of plant growth in Ebb and Flow follows the same. Genetic manipulation by adding (or) removing attributes that sterilize the ability of the plant to confront biological strain that enhances productivity and condition.

Much of the task done for growing plants in space and likewise restricted environments where the inputs need to be under careful control due to limited resources, such as water, also the control of the release of water vapor and other volatile compounds into the atmosphere around the plant.

In plain words, the plants utilize water and the essential elements efficiently, which make Hydroponics—Ebb-and-Flow systems superior to what is possible today.

The Hydroponics—Ebb and Flow systems are verdant and responsive; only if understood correctly, this piece offers information on how the Ebb and Flow system of Hydroponics work.

The part of the plant root:

The plant’s roots in Ebb and Flow systems anchor the plant to the growing medium. Furthermore, the foremost is to act avenue through which water and ions enter the plant for redistribution to every part.

In Ebb and flow systems, the root grows into a much higher volume of growing medium. The roots’ growth depends on the supply of nutrients from the channel, and, in turn, the top depends on the root for water and the required essential elements. The restriction of roots can significantly affect the top growth of the system in an Ebb and Flow method of operation.

An essential thing to remember is that roots require a continuous supply of Oxygen (O2) to remain healthy and functioning.

The efficiency of roots frequently filling blocks of containers; besides, sometimes roots grow through the openings in the outer walls of pots and media containers, which constitutes healthy functioning roots for the Ebb and Flow growing system.

The uptake of Water:

The plant growth in a controlled medium-Ebb and flow system is susceptible to water stress, which significantly influences the plants’ growth rate and advancement.

Water in the Ebb and flow systems is pulled-up by the conductive tissue—Xylem and observes a loss of water from the leaves.

Transpiration happens through the uptake of the continuous column of water from the root cells up to the exposed leaves; the rate of water movement is observed by a potential water inclination within the leaves and the surrounding atmosphere).

This process reduces foliage temperature and provides a physical force for the translocation of elements from the rooting environment up into the upper portions of the plant. For water to uptake (enter the roots), the above-discussed sources (roots) must be wholly functional.

The songs of Ice and Fire (Temperature):

Temperature is another essential factor that determines the growth of roots and the absorption of water and nutrient elements in an Ebb and Flow system.

The maximum root temperature will vary somewhat with the plant selected, but in a vague, root temperatures under 68°F (20°C) bring about differences in the root growth and behavior.

The uptake of water and ions gets shadow in acting as the permeability of cell membranes, and root kinetics get dropped in performance with decreasing temperature. However, the roots can suffer an increased warmth for a shorter while.

The viscosity of water decreases with lower temperature, which affects the foundation of Ebb and Flow— water uptake by the roots.

The roots function the best at about 86°F (30°C) and probably can withstand temperatures up to 95° ̊F (35° ̊C).

Aeration In Ebb and Flow systems:

In the Ebb and flow systems, the plant roots grow in a flow of nutrient solution; thus, there are chances of significant problems that arise with the temperature rise— this is because of the solubility of oxygen is low in the water and decreases significantly with the increase in temperature.

For example, at 32°F(0°C), the parts per million Oxygen in water saturated with air is 14.5, and at 95°F(35°C) is only about 6.8. As a result, with an increase in temperature, plant respiration (theO2 demand) increases rapidly.

Therefore, the nutrient medium in the Ebb and Flow system is to be well-aerated by either bubbling air or oxygen into the nutrient solution. It can also be done— exposing as much of the surface of the nutrient solution as possible to the air by agitation (does not work for sure).

To consider the aeration method in the soil method of growing plants depends on the greater mass of the roots, but in the Ebb and Flow system, the root mass is less a contributing factor. The tag and status of the plants to be ‘nutritional’ and as healthy growing plants need food(carbohydrate) to sustain the roots in an active respiratory condition.

The debt of ions:

Three things to know about this process; the first is that plants take up ions selectively even if the outside concentration and the proportion of elements may be different from those in plants; the following is that the accumulation of ions by the roots occurs across a considerable concentration gradient.

The last is that cell metabolism should render enough energy to the roots to pay the debt of ions to the plants. Any active system of Ebb and Flow shall exhibit—Ion competition, antagonism, and synergism.

For example, a good system prefers —Potassium (K+) uptake over calcium (Ca2+) and magnesium (Mg2+) uptake. The nutrient solution must be carefully and adequately pondered initially and then kept in balance during its use to avoid the hazards of creating nutritional element imbalances.

4. The demands of Essential Elements:

Three requirements that elements had to meet in an Ebb and Flow system to meet up with the demands of food by the plants.

These are as follows—the omission of any element puts up a question for abnormal growth, failure to complete the life cycle, or premature death of the plants. The elements are specific and irreplaceable by any other; the elements affect directly the growth or metabolism rather than some other harsh effects, such as by antagonizing another element present at a toxic level.

Indebtedness of significant elements:

There are as many as nine different elements essential for the plant to grow in the Ebb and Flow system—Carbon, Hydrogen, Nitrogen, Calcium, Potassium, Magnesium, Sulphur, Phosphorous Oxygen.

Carbon, Hydrogen, and Oxygen are supplied with CO2 from the air and H2O from the rooting medium.

The remaining six carry equal importance and are given by dissolving it in the nutrient medium in sufficient concentration and a prudish equilibrium to meet the plant’s requirements.

For example, C, H, O, N, S —constituents of organic material; are essential elements of atomic groups involved in enzymatic processes and assimilation by oxidation-reduction reactions.

Gratitudes to micronutrients:

The Ebb and Flow plants entail considerably smaller micronutrient concentrations than those of significant elements to sustain nutrient element sufficiency. They are critical as those of nutrient solutions. When compared with substantial elements, the optimum quantity of the micronutrients is about 1/10000.

Moreover, as a group is far more critical than significant elements, there are several micronutrients, but generally, the required range is quite narrow. The departure in this narrow range can create deficiency or toxicity below or above, respectively.

Deficiency in the case of micronutrients can usually be corrected easily and quickly, but when dealing with the excess correction can be difficult, if not next to impossible. Particular care shall originate initially to ensure that a micronutrient’s excess concentration is not introduced into the rooting media.

There may be enough concentrations of micronutrients from the natural environment of Ebb and Flow systems—from the water used to make a nutrient solution, the inorganic or organic rooting media, or from contact with piping, storage tanks, and other components of the set-up. Therefore, it is critical to analyze a prepared nutrient solution after constituting it and after contact with its environment to examine the amount of micronutrients.

The dealings with the confusion:

The significant elements listed above are in percentage concentration in the plant’s dry matter, whereas the micronutrients only constitute in concentrations of 0.01% or less in dry matter.

To circumvent confusion with dealings, micronutrient concentrations are expressed in milligrams per kilogram (mg/kg) or parts per million (ppm), and the major elements are expressed in %.

The elements discussed above vary considerably with the chosen variety, the plant section, and scaffold of growth—plus the effect of the level of elemental availability.

The combination of an ingredient in a particular plant part at the known stage of extension, and even its appearance within the plant itself, can provide estimable information for determining the nutritional standing of the plant.

The bonus-list of elements:

Remember, the plants are grown in the soil, consisting of many ingredients. The essential elements that are critical to plant growth are discussed above. However, some added flavor of beneficial elements is proven best for Ebb and Flow systems.

The mentioned above are identified and adopted by the principal of the species. These are species-related elements (almost there are some for every chosen).

For example, a recent test conducted for a nutrient solution medium found that the low concentration of Platinum (0.057 mg/L [ppm]) spurred plant growth for some plant varieties. Still, more superior levels (0.57 mg/L ([ppm]) reduced growth for all species.

The Physical appearance:

The first and foremost thing to note is that apparent indication may NOT appear similarly in all plants. However, this is not the predicament of all the varieties but a speculated insufficiency.

It is advisable to have more than one individual commemorate the symptoms and to proffer an adequately collected plant (leaf) parenchyma individual for elemental laboratory analysis and diagnosis or interpretations. To consider one nutrient element, Calcium (Ca)—The excess symptoms are that plant leaves may manifest characteristic Mg insufficiency indications; in cases of significant excess.

Furthermore, the insufficiency manifestations are that the points of leaves will look shredded for the edges of emerging leaves will stick synchronically, and the fruit quality will be affected. Blossom-end rot will appear on fruits, and the growing tips of roots and leaves will turn brown and die.


It ranges widely, and it can be challenging to ascertain precisely if the water carries few ions. For example, the pH of filtered water is not an easily fathomable perception. If the before-mentioned water is exhibited to air, its pH will diversify depending on the quantity of CO2 adsorbed.

However, this is not as much of an essential factor as most plants can grow in wide ranges of changing pH, and this sign is not an issue throughout the process if the water pH is below neutrality(pH < 7.0).

5. The curious case of Filtering and Sterilization:

Any harmful or suspended material in the water (this latter becomes the nutrient solution) source should be cleaned by the sand bed or a similar filter system to be used in an Ebb and Flow system.

With continuous use in a circulating Ebb and Flow set-up. The dissolved solution is developed with each voyage within the roots and rooting medium. Not only by eliminating elements by precipitation and plant root intake but also by additions generated by the sloughing off of root elements and materials contained in or disturbance to the rooting medium.

The filtering means are generally placed in the outflow line leading to the plant tray from the reservoir. For example, the famous ultraviolet sterilizers effectively reduce microorganisms—done by placing two lamps of 16W in the path of nutrient solution flowing at 3gallons(14L approx. )per minute, yielding a total exposure of 573 J per square meter per hour.

6. The Overall Analysis:

Generally termed as the plant leaf analysis or tissue analysis, it is to monitor the content of the plants that every element and need of the Ebb and Flow plants are filled up.

Great care is to be taken when selecting the sampling part and the Plant part. The regular exposition of plants includes checking; the dead plant tissues, grimy or chemical coated leaves, and reviewing the insect-infected leaves or mechanical churn out of the plants.

7. An open letter:

  • The Ebb and Flow are limited to only some varieties of plants, the root crops such as potatoes, radishes, beets cannot be grown by this technique.
  • Most of the failures in an Ebb and Flow system are associated with the infestation of root infection or the incapability to control the nutrient element conditions of the rooting media that happen in plant nutrient element insufficiencies.
  • The challenging part in setting up an Ebb, and Flow system is to distinguish facts from flow(fictions); misinformation can endanger the plants.
  • Growing suited plants in the Ebb and Flow system is not a method for subduing growing situations that will diminish plant extension such as atmospheric requirement, low or high light strength, irregular air, and root temperatures.
  • Usage of Poor kits.

On a physical level, At its simplest, the Ebb and Flow systems are ideal for heavy fruiting annuals. They are known for their primitiveness, dependability of performance, and low initial investment cost.