Drip System Hydroponics

Types of hydro 1

It is a widely used type of hydroponics, perhaps the most popular, as it resembles the classic agricultural technique of drip irrigation; it very well understood.

Pros

Cons

Simple to set-up. Simple and relatively inexpensive materials

Can lead to nutrient toxicity if not flushed periodically (for the non-recovery type)

Can be used for all plants, fruit-bearing ones included.

The plants need to be above (or generally higher than) the reservoir water line (for the recovery set-up)

It is versatile, allowing for expansion as long as there is space

Drips flow needs to be adjusted as required periodically

Very well suited to plants with large root area as the volume of water used is small (no need for large volume of water to flood the tray).

 

Maintenance is easy and inexpensive. Just make sure the pump and the air pump are in good order and work

 

The set-up

As its name implies, it is a set-up by which the nutrient solution is fed to the plants by drips. The nutrient solution is in a reservoir (can be of any shape but must be opaque not to allow light in to avoid the growth of algae and other microorganisms). The pump is submersible in the reservoir and pushes the solution through tubes to manifolds that then distribute the solution to drip lines.

It is recommended to aerate the nutrient solution for two reasons:

  • to increase the uptake of dissolved oxygen from the roots and increase the growth rate and yields and
  • to ensure that there is enough dissolved oxygen in case algae that consume it exist in the solution.

The growing medium absorbs the nutrient solution and keeps the roots moist. Because the nutrient is supplied from above, there is no concern of not reaching the roots when the plants are still young.

There are two main set-ups of the Drip System.

Recirculating / Recovery set-up

This set-up allows for any excess solution to drain back to the reservoir where it then recirculates back to the drip lines. Because plants have already used nutrients from the solution, the solution that is recovered will gradually have different chemistry to the one initially in the reservoir: different pH and consistency of elements (nutrients). Therefore it is required that periodically you check and adjust pH as well as rebalance the nutrient consistency in the solution.

Non-recirculating / non-recovery set-up

This set-up does not have recovery piping as there is no excess solution at the bottom of the plant container. The dripping system is so carefully adjusted so that the total flow of solution to the plants is as much as they need to absorb at each growth stage.

Although this set-up requires experience and good calibration, it has the benefit of not requiring as much maintenance as the recovery set-up and best of all the solution does not need pH or nutrient adjustment; only refilling with new one.

On the other hand, because there is no run-off the growing medium needs periodic flushing with clean water to remove the accumulation of salts to avoid toxicity.

What you will need

  • A tray that holds the growing medium and the plants
  • A large nutrient solution container
  • Submersible water pump to circulate the solution
  • Air pump with air tube and air stone (recommended, but not absolutely necessary)
  • Tubes and pipes to transfer the solution from the main reservoir to the distribution manifolds and the drips
  • Tubes from the tray to direct the recovered excess solution back to the reservoir
  • Drips and distribution manifolds
  • Growing medium
  • Containers and baskets to hold the plants (if chosen to hold the plants in baskets within the tray)
  • pH sensor
  • Electrical Conductivity (EC) sensor (measures the total salts in the solution)

Aeration

To maintain healthier roots and plants, it is advisable to aerate the nutrient solution, whichever set-up you go for, although not necessary. Aeration, apart from stimulating growth, it can act as a counter-measure against oxygen depletion caused by algae and other microorganisms (if you are not diligent enough with cleaning the tray etc).

So in this case, you will need an air pump, tube and air stone to the bottom of the solution reservoir.

Typical Problems

Algae, bacteria and other microorganism growth in the solution. Avoid using transparent containers/reservoirs where light can pass through. Light encourages microorganisms to grow which can change the chemistry of the solution, reduce the efficiency of water and oxygen absorption by the roots which can lead to root rotting, ultimately reducing yield.

Overwatering. With the drip system it is highly unlikely that there will be any issue with the water level in the tray, as there will be a drain hole to remove any excess (except in the non-recirculating set-up). In any case, accumulation of water in the tray means that either the drain hole is clogged (for the recirculating set-up) or that the dripping flow is too high (for the non-recirculating set-up) and it needs to be dealt with.

Thirst. It is unlikely that thirst will be an issue in this type of hydroponics, because inherently you are constantly providing nutrient solution to the growing medium and plants. BUT if signs appear, you need to adjust the drips for high flow.

Oxygen starvation. When roots do not get enough oxygen, they can be damaged and die. Early signs can be leaves that become wilt, distorted or not growing to their expected size. Past that level, the leaves can yellow and drop. If the condition is not taken care of, the entire plant can wilt, stems will start dying and the entire plant will eventually die.

If you have observed these signs, try the following one by one:

  • Ensure that you clean the reservoir or whichever part of the set-up shows visible algae growth
  • Ensure that your water reservoir is opaque and does not allow for light to penetrate
  • Introduce aeration (air pump, tube and air stone) if you don’t have it already
  • If you do have it, check that the air pump works and that bubbles come out of the air stone
  • If the air pump works but little or no bubbles come out of the air stone, check for any air leaks along the tubes and joints

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