First off, if you are new to growing on Ebb and Flow benches (AKA: flood benches, ebb and flood benches, sub irrigation benches, etc.), we find it is best to simply think of the Ebb and Flow benches as a new way of delivering water and fertilizer to your crop(s). In other words, the grower should make the same decisions about the timing of irrigation, and the application of fertilizer as he/she would with any other irrigation method. Having said that, here are a few differences that you will want to watch out for when irrigating your crop with Ebb and Flow benches:
Growers find that they will typically need to irrigate the crop a little LESS frequently than with other watering methods. This is mostly due to the fact that Ebb and Flow benches apply the irrigation water to the crop very evenly and very thoroughly. This means no going back frequently to "touch up" edges or corners, etc. Also since the watering was even and complete, there will not typically be pots that are drier due to receiving less water, as can happen with hand watering, and other over head types of water delivery. Since it is so easy to water the crop with an Ebb and Flow system, don't make the mistake of over watering by watering too frequently.
One important difference between an Ebb and Flow system and other irrigation methods is that there is no leaching. Water is always taken into the root media with each irrigation cycle, but it is basically a one way street. For this reason it is VERY important to not over fertilize. The recommendation usually given (from much research in the US and Europe in the 1990's) is to fertilize at every irrigation (constant liquid feed method) with a solution that is one half the strength (or less) that you would use with your previous irrigation method. In other words, say you grow pot mums, and used to water with 250 ppm nitrogen (hand watering, drip irrigation, etc.). When growing the same crop on Ebb and Flow benches, try using 100 to 125 ppm nitrogen. The idea is to give the plants just what they need and no more, This is why you save so much money on fertilizer with an Ebb and Flow system.
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