A TALE OF TWO SYSTEMS
The two popular types of watering systems I am about to compare in this article are ebb and flow , and drip irrigation . Deep water culture ( DWC ), recirculating deep water culture , and nutrient film technique ( NFT ) are other commonly used systems , yet substantially different from these two — they will be compared in future articles . Let ’ s get on with the comparison at hand , starting with some simple definitions :
Ebb and Flow
Ebb and flow is a form of hydroponics that is known for its simplicity , reliability of operation , and low initial investment cost . In this system , pots are filled with an inert medium that is usually not soil , but something much more porous , yet capable of anchoring the roots and functioning as a temporary reserve of water and solvent mineral nutrients . The hydroponic solution alternately floods the system and is allowed to ebb away .
Drip Irrigation
Drip irrigation hydroponic systems are also simple and economical . True drip irrigation utilizes drip emitters that actually drip water rather than spray or run it . Drip irrigation for outdoor crops was developed in Israel to maximize the amount of scarce water being used to grow outdoor crops . Drip avoids loss of water through reduced evaporation , leaching , and runoff in the outdoors . In hydroponics , the leaching action really doesn ’ t come into play unless the system is allowed to run far past saturation .
When new growers are considering which type of grow system they might want to use , there are a few important aspects they need to look at :
• Yield potentials
• Overall efficiencies
• Operating and nutrient costs
• Set-up complexity and costs
• Operational complications
• Likelihood of pest and disease problems
• Maintenance and material replacement costs
Yields – Root & System Size
If a drip system fails to evenly distribute moisture throughout the root system , ebb and flow , which naturally does this , will out-produce a drip system . However , if there are sufficient and properly spaced emitters in the drip system , there will really not be a difference between these two systems when it comes to yields . Proper watering frequency throughout the maturity of the crop ’ s cycle , proper nutrients , and adequate lighting levels will have the most impact on yields . To compare root system differences between these hydroponic systems , we need to consider how each system affects root growth , each system ’ s limit for root growth capacity , and aspects that may damage root growth and vigor . Larger and healthier root systems produce greater yields . Smaller pots restrict the ultimate size a root system can grow .
However , either of these systems can utilize larger pots . The table size for the ebb and flow systems can be an issue for a large number of large pots . With drip , the pot size and quantity of plants is basically limited by the size of the growroom — not the grow table — giving drip systems the advantage in size capacity . Another factor for producing larger root systems is the amount of foliage growing for the plant , and hence photosynthesis .
MAKE SURE you choose the right grow media for your operation and then design the set-up to match that .”
124 Maximum Yield USA | December 2016