Drip Irrigation Techniques for Cannabis

Drip Irrigation Methods for Cannabis Growing

Drip Irrigation has become one of if not the most popular watering method used for micro cultivation and legalized commercial producers of Cannabis.  As the most efficient method for delivering both water and nutrients Drip Irrigation (a.k.a. Micro Irrigation) offers considerable savings to Cannabis growing operations while being one of the most inexpensive systems in terms of initial capital outlay.

When considering Drip Irrigation for your Cannabis facility, there are several methods to choose from.  Virtually all methods will provide excellent results but do vary in terms of their initial cost, durability, and ease of assembly.  There are also considerations such as the size of the Cannabis operation that need to be addressed when choosing the right Drip Irrigation Method. 

We will now look at the most common Drip Irrigation Methods for Cannabis in use today and provide benefits and drawbacks of each method.  We have also provided in depth summaries of each method including illustrations and examples from actual installations we have provided design assistance for.

Multi-Port Drip Irrigation Manifolds

PVC Manifolds are available in several configurations from 4 to 12 ports.  For Cannabis Irrigation it is recommended to use pressure compensating manifolds for precise output from each port for consistent results throughout the growing area. 

Multi-Port manifolds are assembled using solid PVC making the system both sturdy and clean in appearance.  Depending on the flow rate, many manifolds can be used with either Drip Stakes or Spray Stakes. 

Advantages:

• Centralized output for easy cleaning and maintenance (Emitters can be replaced or flow rate changed)
• Clean and durable assembly.
• Interchangeable emitters for variable flow rate options.
• Ability to use both Drip Stakes and Spray Stakes

Disadvantages:

• Higher initial capital outlay.

Single Emitter Drip Assemblies

Popular with both large licenced producers and micro-cultivation operations, Single Emitter Drip Assemblies offer excellent results and require little effort to set up.  As with Multi-Port Manifolds we always recommend using Pressure Compensating emitters which are available in several outputs from .5 to 10 gph (2 – 37 lph) although .5 to 2 gph are most commonly used for most Cannabis. 

Assemblies are available fully assembled or can be made with the combination of an emitter, micro tubing (Netafim Super Flex is recommended for all assemblies) <link> and a barbed drip stake.  The emitter is then inserted/punched into the distribution tubing (solid drip line)<link>.  Depending on the size of the container being used, it is usually recommend having more than one dripper per Cannabis plant.

Advantages:

• Low Cost and Simple Assembly.
• Versatile layout (you can add dripper as needed by simple putting another one in the distribution line.

Disadvantages:

• If emitters clog they need to be pulled and replaced in a new location on the distribution line, which may result in system replacement over time.

Single Emitter Multi-Port Assemblies

Similar to Single Drip Assemblies, Single Emitter Multi-port Assemblies utilize a combination of a single emitter, a multi-port manifold from 2 to 8 ports (most commonly 2-4 ports) and a drip assembly.  The emitter used in these assemblies is unique from others as it is configured to accept the manifold on top of the emitter, so traditional emitters cannot be used.  Emitters for multi-port assemblies come in 1 and 2 gph outputs.  Most 2 and 4 port manifolds can also be stacked allowing you to add additional drip stakes without adding additional emitters to the drip line.  Another unique characteristic of multi-port assemblies is the use of Labyrinth Stakes <link to Multi port assemblies’ page> over traditional barbed stakes.  Labyrinth stakes regulate the water flow by pushing back to the emitter to ensure even flow from each port.   If you were to use a traditional open flow barbed drip stakes the water output would go to the port of least resistance resulting in uneven flow out of the manifold.  The labyrinth stake provides a small amount of push back to the emitter to ensure the micro tubing is full on all ports prior to allowing water to escape for equal distribution of water to each cannabis plant.  The stakes are available in both 4 and 6 inch lengths.

Advantages:

• Low Cost and Simple Assembly.
• Versatile layout (you can add dripper as needed by simple putting another one in the distribution line.
• Stackable Manifolds for ability to add drippers to single emitter as needed.
• Splitting Emitter output between Cannabis plants enables longer drip line runs.

Disadvantages:

• If emitters clog they need to be pulled and replaced in a new location on the distribution line, which may result in system replacement over time.
• Emitters only available in 1 and 2 gph configurations.

Spray Stake Assemblies

Spray Stake Assemblies have grown in popularity with Cannabis growers who are cultivating in large containers and natural outdoor growers who are growing with no container.  Spray stakes provide broader coverage through a fine spray which is desirable when using soil based growing media to obtain even water coverage throughout the cannabis root zone.  Although they are similar to single emitter assemblies they require higher output to produce the spray.  The higher output requirement will often lead to water availability issues and often limits the amount of canopy that can be watered at one time, or may require watering in several zones for a given area.  This can also be an advantage when shorter run times are desired putting more water on the root zone relatively quickly. 

Spray stakes operate with as little as 2 gph and can be installed with flow rates up to 10 gph per stake.  In addition to Single Emitter Spray Assemblies, Stakes can also be used with multi-port manifolds such as the DIG TOP manifold provided the emitter output is greater than 2 gph.

Advantages:

• Low Cost and Simple Assembly.
• Versatile layout (you can add spray assemblies as needed by simple putting another one in the distribution line).
• Wide Variety of Flow Rates Available.
• Can be used with both Single Emitter and Multi-Port PVC Assemblies.

Disadvantages:

• If emitters clog they need to be pulled and replaced in a new location on the distribution line, which may result in system replacement over time.
• High water use, leading to increased zoning for the growing canopy.
• Higher overall cost than Single Drip Assembly set ups.

Halo Drip Assemblies

Halo Assemblies for Cannabis growing are great for larger container and provide gentle watering around the root ball.  Halo Assemblies can either be purchased as preformed Halo's (Netafim Netbow), or can be assembled from scratch using Drip Emitter Tubing with emitters built in at 6 or 12 inch intervals.

Advantages:

• Simple assembly.
• Uniform surface wetting for all round root development even at the surface.
• Can be used in conjunction with pressure compensating emitters at the header line for precision watering doses.

Disadvantages:

• Clogging can be an issue if not properly filtered, although Netafim Netbow employs superior Typhoon emitters with best in class anti-clogging.
• High water use, leading to increased zoning for the growing canopy.
• Higher overall cost than Single Drip Assembly set ups.

Ref 10030