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DIY Hydroponics - Building a Flood and Drain Hydroponics System


Our DIY Flood and Drain Hydroponics System starts with Two tubs Flood and drain hydroponics systems are also sometimes called ebb and flow hydroponics. Building a simple flood and drain hydroponics system is easy and lots of fun. Our DIY flood and drain hydroponics system starts with two tubs, a large one which will be the nutrient reservoir and a smaller one which will be the grow bed. As far as nutrient reservoirs are concerned this one is probably too large for the job for such a small grow bed but it allows scalability, once youve got the hang of growing with one grow bed you might just feel the need to add more and filled to the brim this reservoir will probably support four grow beds of this size. Our shopping list is pretty small-
  • One second hand tub about 80 litres capacity
  • One second hand tub about 40 litres capacity
  • One 13mm (1/2") Fitting with screen
  • One 19mm (3/4") fitting with extensions and screen
  • 13mm (1/2") Flexible Plastic Pipe
  • 19mm (3/4") Flexible Plastic Pipe
  • One aquarium pump
  • Timer - Not mandatory but really convenient
Of course the tubs dont need to be second hand, new ones will work just as well. In our example here the 80 litre tub was purchased second hand from a hydroponics supplier who stocks second hand equipment and it was a nutrient reservoir in its previous life. Our 40 litre tub was our neighbours bottle recycling tub until the council provided us with new recycling bins. The pump was purchased new at our hydroponic supplier and features a 6 metre long power cord, very handy for avoiding having an electrician come out and supply a waterproof outlet. The fittings were also purchased from our hydroponics supplies shop and arent a necessity, you can just drill holes and stuff pipes into them sealing the joints with silicon for that genuine DIY flavour. For the few dollars the proper fittings cost and their tendency not to leak or block I personally feel they are worth the investment. This hydroponics system will run for years after all.

Install the fittings onto the grow bed

Growbed Overflow - Note the spacers under the screenOur first step is to create two holes in the bottom of the growbed to accommodate the tub inlet and outlet fittings. You can use either a drill or holesaw for this task and the objective is to make the fitting a good fit in the hole. If there is too much clearance around the hole the O-ring may not seal properly and you will end up with a leak.

Our pump will attach to one of the fittings and will pump nutrient solution into the bottom of the growbed. The outlet fitting has spacers to elevate the screen so that when the growbed is filled sufficiently the excess nutrient solution will flow back to the reservoir. When the pump is turned off the nutrient solution will drain back through the pump and completely empty the growbed. The two fittings are identical except the inlet accommodates a 13mm (1/2") pipe and the outlet a 19mm (3/4") pipe.

Install the pipework and pump

Cut the flexible pipe roughly to size and push them onto the fittings as pictured. The larger diameter pipe is for the overflow and the smaller one is for the pump. Remember that the overflow is the one that has the spacers to make it sit higher than the inlet that the pump connects to. Sit the pump in the bottom of the reservoir and fit the smaller diameter hose to it. You may need to trim the hose so that the pump sits below the inlet without any loops of pipe that can cause problems down the track. Our pump used here has a 6 metre long power cord, more than enough to run back into the work shop through a hole in the wall. Now that its assembled fill the reservoir with some water and switch it on! The water will be pumped into the tank through the tub inlet and fill the growbed until it reaches the level of the outlet which will return the excess nutrient to the tank. When the pump turns off the growbed will completely drain back through the pump. Notice that the inlet and outlet are positioned on the bottom of the growbed so that if they leak it will drip harmlessly back into the reservoir.

The completed DIY Flood and Drain Hydroponics SystemNow that we have double checked that everything works as it should its time to fill the growbed with some growing medium. We've decided to use hydroclay because its light and drains well. Rinse the hydroclay thoroughly to get rid of excess dust but dont be surprised when your nutrient solution turns red like ours has. It seems to be just about impossible to rinse off all of the dust but it is not harmfull to the plants and it will all be gone after a few tank changes. Fill the growbed so that the medium is at least 5cm (2") above the height of the water when the growbed is flooded. Bear in mind that when you put new plants in the system the plant roots will have to grow to below the high water mark before they will be able to drink. I use 5cm cubes to germinate my seedlings so they will not require hand watering to get them started.

All that is required now is to mix your nutrient solution in the reservoir and add some plants. You home made flood and drain system is complete!

To learn grow plants your new flood and drain hydroponics system read our Using a Flood and Drain Hydroponics System tutorial as it is sure to be of help to you. It uses this system to demonstrate how easy flood and drain hydroponics is to use.