How toGrow BIG Plants heavy PVC pipe or 2x4s . Remember , the stand must be able to hold the weight of not only the tray , but the nutrient solution , plants , and grow media . The height of your stand is reliant on the size of the next component — your reservoir .
VIVOSUN — NFT Hydroponic PVC Grow Kit ( 1 Layer , 36 Plant Sites ) retail for $ 129.95 at YRG . Similar kits are available at grow stores in you area .
Situated below the flood tray , a reservoir , typically a bucket or tote , will hold your nutrient / water solution . The size of the container is dependent on the size of the tray and the number of plants you ’ re planning to grow . An easy way to calculate the maximum size of the reservoir you ’ ll need is to determine how many gallons of water your flood tray can hold without any plants in it . Keep in mind that once your plants are in the tray , they ’ ll take up a certain amount of space , meaning you won ’ t need the full amount of water from your calculation when it ’ s time to fill the reservoir . Here ’ s a simple formula for the holding capacity of your tray in gallons : Height ( inches ) x Length ( inches ) x Depth ( inches ) x 0.004329 . As an example , our 3 ’ x 3 ’ x 0.5 ’ tray would hold 33 gallons of water ( 36 ” x 36 ” x 6 ” x 0.004329 = 33.7 gallons ). With your tray now sitting on a stand above your reservoir , add an ebb and flow fitting kit . Fitting kits generally include two fittings along with grommets to create waterproof seals . One fitting allows water to be pumped up from the reservoir , and the other allows it to drain back down . These should be installed on the bottom of the flood tray either in pre-drilled holes or in specified locations that must be drilled during setup .
Place a small water pump at the bottom of the reservoir and connect it via flexible poly tubing to its corresponding fitting in the flood tray . Plug the water pump ’ s power cord into an outlet timer . This is what will allow you to create the cycle of flooding and draining , the frequency of which depends on the type of grow media you ’ re using and the speed at which it dries out in your environment . You want to avoid situations where plant roots fully dry out and those in which they remain oversaturated for extended periods . In our example , we ’ ll use clay pebbles ( also called LECA — light expanding clay aggregate ) and set the timer to run for 15 minutes every 2.5 hours .
● Note : If your drain fitting isn ’ t directly above the reservoir or you have a lid on your reservoir , you ’ ll also want to use flexible tubing to route the water back to the reservoir .
Roots require oxygen just as much as they require water , so some growers will also employ an air pump to help oxygenate the water in their reservoir . A pump is placed outside the reservoir ( running continuously ), and air is forced through flexible tubing to an air stone placed in the water / nutrient solution .
● Note : While this step can improve the oxygen levels in your solution , it ’ s not necessary . The process of flooding and draining the tray itself is enough to provide ample oxygen for the water .
We ’ re ready to add our plants to the tray . Select containers or net pots that drain well and are resistant to mold ( i . e ., no fabric pots ). They don ’ t need to be extremely large since you ’ ll be providing their roots with all the nutrition they need through a nutrient solution . Even a 1- or 2-gallon plastic pot will be sufficient .
Fill the containers with clay pebbles and insert your rooted seedlings or clones so that , when fully flooded , the solution will reach the bottom of the roots . If you want to avoid containers altogether , you can opt for a grow medium such as Rockwool , where large solid cubes hold your plants and are placed directly onto the flood table .
You can buy Ebb and Flow Starter Kits with buckets like this from YRG and other grow stores in you area .
Even if you don ’ t plan to grow extremely large plants , the small containers used in ebb and flow almost always result in top-heavy cannabis . You ’ ll likely need some type of training system or trellis netting to support your canopy and keep everyone upright .
As always , monitor your nutrient feeding schedule , pH , and system cleanliness ( all topics that we ’ ve covered in previous issues of The EVOLUTION Magazine can be viewed at www . TheEvolutionMag . com ). Watch for next month ’ s issue , when we ’ ll investigate Continuous Flow , also known as Nutrient Film Technique ( NFT ).
For more information about YRG , visit
www . year-roundgarden . com or call 816.216.6917 and be sure to tell them The EVOLUTION Magazine sent you .
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