The Ins and Outs of Ebb and Flow

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The Vault Cannabis Ins and Outs of Ebb and Flow


Today we are going to take an in-depth look at one of the more popular hydroponic growing systems. The reason for its popularity lies largely in its simplicity and the fact that it is easy to set up and monitor. This is definitely one of the better systems for those who are just becoming acquainted with hydroponic growing. Ebb and flow is also known as flood and drain or simply a flood table. It doesn’t take up too much space and doesn’t require a lot of high tech equipment. It is also versatile and can be altered to accommodate all shapes and sizes of plants. Despite the simplicity of the system it is often also used by expert growers as the results with ebb and flow are often very impressive.


How Does It Work?


The basic mechanics of ebb and flow are much as you might expect. The set up essentially works by temporarily submerging the roots in a nutrient solution before allowing it to ebb into a reservoir. It floods the roots several times a day to ensure they get the nutrients they need as well as the air they need. Not only does the drying of the roots allow for oxygen intake but it ensures that they don’t begin to mould or rot. The plants themselves are potted in an inert growth medium, this doesn’t need to supply the plants with nutrition. This medium is contained by a basket that is covered in holes to allow the roots to grow through. The pots are placed in a growing tray and this is where the nutrient solution is pumped in and allowed to flow out.


Why Use It?


There are a number of advantages to using the ebb and flow method. Once it is set up it is very self-reliant and doesn’t require much care. The temporary flooding also removes a number of issues that tend to come with other hydroponic setups. They are also small, quiet and won’t rack up a huge electric bill.


Potential Issues


If something does go wrong such as a power cut the whole crop will be ruined. This is a risk you take with most hydroponic growing. It is also important to check the system every once in a while to ensure there are no blockages forming. If the system gets blocked up it can result in the system not draining properly. If the roots can’t try they will get mouldy and this will also likely kill the plants.


Nutrient Solutions


Choosing the right nutrient solution is important and we should definitely have a look at it before we start setting anything up. It is easy to purchase nutrient solutions online, but we need to know what to look for. There are three primary nutrients that need to be present in the solution. These are Nitrogen (N), Phosphorus (P), and Potassium (K). Thought these are the primary nutrients required an ideal solution should have the following list:


– Nitrogen (N)

– Potassium (K)

– Phosphorus (P)

– Magnesium (Mg)

– Iron (Fe)

– Calcium (Ca)

– Sulphur (S)

– Zinc (Zn)

– Chlorine (Cl)

– Boron (B)

– Manganese (Mn)

– Copper (Cu)

– Molybdate (Mo)


Many growers will use a variety of solutions during different grow periods. This is because, just like humans, plants need different nutrient levels at different times in their life cycle. For example, many experts claim that during the vegetative stage plants need high nitrogen, medium phosphorus and high potassium. During flowering, however, they need low nitrogen, medium-high phosphorus and high potassium. It is a good idea to thoroughly research your solutions before buying to ensure the best possible results.


How to Set It Up


We will need:


  • A reservoir with a lid
  • A growing tray
  • A water pump with a timer
  • Rubber tubing
  • An inert grow medium (Rockwool cubes, coarse sand or clean gravel are ideal)
  • Nutrient Solution


The first thing we need to do is create holes to attach the reservoir and the tray together via the tubing. Drill two holes in the reservoir lid and another two matching holes in the tray.


Then we connect two of these holes with rubber tubing that will go above the level of the water, this is called the overflow tube. If the water level gets too high it will be caught by these tubes and fed back into the reservoir.


The other two holes will house the flood pump and drainage tube. The pump in the reservoir will be attached to this tube and will monitor the ebb and flow. As far as timed pumps are concerned pond pumps work just fine and aren’t very expensive.


Then we are ready to place the plants in their grow medium and little baskets or pots with holes in the bottom into the grow tray. The pots need to be about twice the height of the tray to avoid the top of the plants getting wet.


Finally set the timer on the pump, it should flood and drain the plants at 15-minute intervals. The amount that the flood and drain needs to happen depends very much on the climate and the medium. Some mediums, such as Rockwool drain quite slowly, pair this with a colder environment and we will only need to flood and drain about twice a day. However, in a warmer climate with a faster draining medium such as gravel or sand, we may want to push it up to four-six times a day. As always it is important to watch the plants and see how they are responding to your current set up.


After we’ve done this we simply fill the reservoir with nutrient solution and voila.


Once your set-up is complete it should pretty much take care of itself. As we said earlier it is still vital that we keep an eye on the system to watch for any possible faults or build up. It is also always important to watch the plants for any signs of sickness or nutrient deficiency.


Of course, as always it is vital that we do plenty of research before embarking on growing a crop, especially if we are new to it.


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Remember: It is illegal to germinate cannabis seeds in many countries including the UK.  It is our duty to inform you of this fact and to urge you to obey all of your local laws to the letter.  The Vault only ever sells or sends out seeds for souvenir, collection or novelty purposes.

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