Step One – Growbed and Reservoir
Preparing the Growbed and Reservoir
At the core of our DIY hydroponics system are two heavy-duty plastic tubs, one for the grow bed and one for the nutrient reservoir. These plastic tubs don’t necessarily need to be new but if you do source second-hand tubs make sure you know their history and what they have been used for.
If they have been used to store or contain chemicals, fuel or oil give them a wide berth as it is likely that these contaminants will still be present in some quantity and can affect the growth of your plants or taint your produce.
Regardless of whether they are new or second-hand let’s start by giving them a wash with plain fresh water before we start working on them.
The nutrient reservoir requires no work at all for it to serve our purposes however the grow bed will need to have the inlet and outlet fittings installed. If you use the type of inlet and outlet we recommend (purchased from a DIY hydroponics supply shop) then the grow bed needs to have two holes made in the bottom to accommodate them.
To determine where these holes should be made put the grow bed on top of the reservoir in the position it will be in when its assembled and mark where the holes should go so that both the inlet and the outlet will protrude into the reservoir.
Make the holes big enough so that the thread on the fittings is a close fit but they slide in and out of the holes without being forced. The rubber o-ring makes a nice template. You can use a hole saw or a drill to make the holes.
Remove any dags or burrs with a file and install the fittings so that the o-ring is inside the grow bed and creates a seal. Tighten the fittings so that they are finger tight and you will find that they will not leak, there isn’t a great deal of pressure there anyway.
One advantage of this simple design is that most leaks are not a problem anyway as the fittings are inside the reservoir and any leaks will drain back into the tank and be contained anyway. The screens on the inlet and outlet will prevent any pipe blockages that would cause a nutrient solution to be pumped over the floor.
Flip the grow bed over and place it on top of the reservoir in the position that it will eventually run in. Install the spacers on the grow bed outlet to give your system an appropriate high water mark. Once again, there is no magic formula for this and near enough is good enough within reason.
Your high water mark should be about 5cm (2 inches) below the top of the growing media and you don’t need to fill the grow bed right up to the top either, this system has about two inches from the top of the media to the top of the grow bed. Don’t forget to install the screens on the fittings as they are crucial in preventing blockages.
Our photos to the right and below this paragraph should give you a pretty clear idea of where everything should go. You can clearly see the difference in the heights of the inlet and outlet as well. The inlet is the one without the spacers. Don’t get them backward or things won’t quite work as planned.
Step Two – Plumbing
Plumbing the Pump and Pipes
Our DIY hydroponics system only has two pipes and one pump to connect so we can hardly call it complicated plumbing. You should have two short lengths of flexible plastic pipe if you followed our shopping list, the 19mm (3/4″) pipe should connect to the grow bed outlet (the one with the spacers) and the 13mm (1/2″) should connect the pump to the grow bed inlet.
Getting the lengths of these pipes right is pretty easy if you cut them to size once everything is in place. So at this point lets just get our short lengths of pipe and slide them onto the appropriate fitting on the grow bed.
Now its time to place the pump on the bottom of the reservoir or nutrient tank as its sometimes known. Our grow bed inlet is on the right-hand side of the grow bed so we will put the pump in the right-hand back corner of the reservoir where it will be tucked out of the way.
Run the power cable wherever you decide is best before you put the grow bed back in place. We have routed ours out of the back of the reservoir. Once you have the aquarium pump in place and are satisfied with the location of your cable put the grow bed back in its place on top of the reservoir.
Next, we need to trim the pipes to size. The return pipe, like most of our system, doesn’t really have a functional size and in fact, doesn’t really need to be there at all. If you don’t have one you might find the sound of splashing water perhaps a little annoying after a while. Trim the return pipe so that it gently curves off the bottom of the reservoir.
Trim the feed pipe so that it attaches to the pump with just a little bit of slack so that you can move the pump around a bit. Now that your plumbing is complete we’re starting to get to the fun side of things. Fill the reservoir with plain water and switch the pump on.
Water should enter the grow bed at a reasonable rate through the lower fitting and fill it to the level of the higher fitting and drain back through it into the tank (pictured below). Turn the pump off and the water should drain back into the tank via the feed pipe leaving the grow bed empty.
Step Three – Fill the Growbed
Fill the Growbed
Now we have our DIY hydroponics system flooding and draining satisfactorily switch the pump on and allow the grow bed to fill so we know where the high water mark is. This will change slightly when we put media into the grow bed so it doesn’t hurt simply to leave it running.
Grab your fresh bag of media, in our instance we are using hydro-clay, and open it up. If you stick your hand in the bag of media you will notice it comes out red and dusty so washing the media in fresh water is a good step before filling your grow bed with it. I usually put the media into a reasonably sized plant pot and use the garden hose to give it a good rinse.
After you have rinsed your media as best you can put it into the grow bed so that the surface of the media is 1″-2″ above the high water mark. This will inhibit moss from growing across the top of your media. At this point, despite your best efforts, you have probably found that the clean fresh water that was in the reservoir before you started filling the grow bed has been replaced by horrible discolored stuff instead.
It is a good idea to run your pump for a few hours when you have new media and circulate plain water through it to rinse the dust off. The dust is not particularly harmful and you will find it settling on the bottom of your tank for a few tank changes at least.
Once you have circulated plain water through your new media for a few hours empty your reservoir, give it a quick wash out with a garden hose and then refill it. At this point its a good idea to graduate your tank, that is put scratches or marks on the side of it to show how much nutrient it contains. This can be very handy when mixing your nutrient.
We just use a 10 liters bucket, put in one bucket and put a scratch on the side of the tank to represent 10 liters, another bucket gives the 20 liters mark and so forth. Fill the tank to an appropriate level, 40 liters in the case of our reservoir and then add the appropriate amount of nutrient (read the label on your nutrient bottles) to make your first tank. Your hydroponics system is now ready to start growing!
Step Four – Start Growing For Your DIY Hydroponics
How to Use Your DIY Hydroponics System
Now that we have finished constructing our hydroponics system the final of our four steps is to learn how to use it. Using our DIY hydroponics system will prove to be just as easy as building it was and you will find a great deal of pleasure can be found in building and using a do it yourself project such as this one. And you will be amazed at how well your chosen plants will grow in such a simple little system.
Plant the Hydroponics System Out
At this point, our DIY hydroponics system is ready to be planted out. Hydroclay and many other gravels used in hydroponics don’t really lend themselves to seeds being directly planted into them as they tend to get lost, float away or simply not get the initial moisture required to germinate.
Because of its large particle size, the plants have a difficult time getting their roots anchored during the critical initial stages of germination. This is not a problem of course with more advanced seedlings and young plants so we need to start our seedlings elsewhere and move them into the system when they are big enough.
This can actually have some advantages as far as keeping your hydroponics system productive as many plants in the seedling stage do not grow very quickly at all and starting them elsewhere and moving them into the hydroponics system can save you several weeks of reduced productivity.
If you start your seedlings a few weeks before the current crop in the system is done you will have healthy young plants ready to plant in the system when the current crop finishes.
You can start your seedlings in rockwool cubes or in soil depending on your preferences. I prefer rockwool cubes as they minimize transplant shock and the plant hardly knows that it has been transplanted. You can read about starting seedlings in rockwool on our Starting Hydroponic Seedlings page.
Once you have your seedlings started in rockwool simply plant them in their cubes directly into the hydro-clay, making sure that the top of the cube is level with the top of the hydro-clay.
As an alternative you can start your seedlings in soil or, if you are eager to get your system running for the first time, you can even go to your local nursery or garden center and buy a punnet of seedlings. To plant them in your DIY hydroponics system gently remove the seedlings from the punnet and divide them into individual plants.
Gently wash the soil from the root system of the seedling, dig a hole in the media of your hydroponics system, gently place the plant into the hole so that the root system will be covered to the same level as when it was in soil and then push the hydro-clay into the hole to cover the roots. If this is done gently the plant should not suffer and it will adapt well to the direct to the roots nature of hydroponics.
The Flood and Drain Cycle
Clever readers will prefer to have the pump operate automatically using a cheap plug-in timer that can be purchased from most supermarkets, hardware stores, and hydroponics suppliers.
There is no set formula that can be applied to how often your grow bed should be flooded as things such as temperature, humidity, and other climatic factors will be different depending on your location.
Most growers with a hydroponics system such as ours will start out flooding their grow bed for 15 minutes every two hours during daylight and not at all at night. If it is particularly hot at night, say over 30 degrees celsius you might consider flooding the grow bed a couple of times at night as well to relieve temperature stress in your hydroponic garden.
Try a few different watering intervals if you want to see if things will grow better and see how you go. Do not let the plant roots completely dry out during the day.
The Nutrient Solution
Hydroponic nutrients usually come in a two-part solution, part A and a part B that should never be mixed directly together except in dilution. Fill your tank with plain water and then add the two different parts of the nutrient solution to the tank, not to each other and then the tank.
Most nutrients come in two formulas, one for the vegetative stage of growth and the other for the flowering/ fruiting stage of growth. The main difference is the N:P:K balance of the nutrient, as the plants grow they need more nitrogen (as an example) during the vegetative stage than they do during the flowering/fruiting stage.
Once the plants start to flower they should be changed to a flowering formula. This is yet another example of the increased amount of control you get over your plants growing conditions with DIY hydroponics. If you don’t want to buy both then you can simply use nutrient for the flowering stage of growth.
When you mix your nutrient solution follow the directions on the bottle, for example, the label may state that you should mix the nutrient solution at 5ml/liter, 5ml of nutrient part A and 5ml of nutrient part B for every liter of water in your reservoir.
If you have 50 liters of water in your tank you should add 250mls of part A and 250mls of part B. You will notice that the nutrient level in your reservoir will drop over the space of a few days and this can present a problem in that a large amount of your water loss will be from evaporation.
The water in your tank will evaporate and leave the nutrient behind, effectively making your nutrient stronger to the point where it can be detrimental to the plants.
The best solution to this is to top the tank up to the original level with plain water, it won’t dilute your nutrient much and it will prevent the plants from being burnt by a nutrient mixture that is too strong.
It is quite possible to measure the actual strength of your nutrient solution using a CF truncheon purchased from a hydroponics supplier or alternately an aquarium nitrate test kit that can be purchased at most pet stores. This is something you will most likely wish to do in the future once the hydroponic bug bites you really hard.
There are two scales to determine your nutrient strength, parts per million (ppm) or electrical conductivity (cF). Different plants prefer different strengths of nutrient and this is another area that with the right equipment you can gain additional control over your hydroponic garden.
Consider having a look at this Hydroponic Nutrient Strength Guide as it contains a pretty good list of commonly grown plants and the appropriate nutrient strength for each plant.
Over a period of time, the nutrient solution in your tank will become depleted and should be changed. For high energy plants, this should be done every week and every two weeks for other plants.
Nutrient salts will build up in your hydroponic media and this should be flushed out every four weeks or so to avoid the media becoming toxic to the plants. This is easily achieved by dumping your nutrient solution and replacing it with fresh plain water.
Leave the pump turned on for 24 hours straight while it circulates this fresh water through your hydroponics system. After 24 hours discard the water and mix your plants a fresh tank. This is the whole process for your DIY Hydroponics.
How a Flood and Drain Hydroponics System Works
There are a number of different methods of hydroponics and each one operates a little differently from the others. Virtually all methods of hydroponics provide better results than growing in the soil if well tended but some techniques are higher maintenance than others.
We have selected the flood and drain method for our do it yourself hydroponics system because the system will be very easy to build, resistant to leaking, produce excellent results and be really simple to use. And best of all, if you follow the directions, it will be automated and require very little in the way of work to keep it going.
So How Does Our DIY Hydroponics System Work?
Its really easy to see how if you study our diagrams. Our hydroponics system is based around two plastic tubs, one will be our nutrient reservoir and the other will be our grow bed. The grow bed contains our plants which are grown in a suitable hydroponic media such as hydro-clay (pictured above) or gravel that performs some of the jobs soil would do in a traditional garden.
The media provides a place for the plants to anchor their roots and in a flood and drain hydroponics system the media should drain fairly rapidly to a large particle size is required. Definitely go for hydro-clay, scorer or a similar volcanic media.
Underneath the grow bed is the reservoir which contains the nutrient solution. The nutrient solution is really just fertilizer mixed with water that the plants can drink to get the essential nutrients and water that they need to grow.
The reservoir must be at a lower level than the grow bed so that gravity will allow the nutrient solution to drain back into the reservoir once the pump has stopped. Inside the reservoir is a pump that pumps the nutrient solution into the very bottom of the grow bed via the feed pipe.
The most common type of pump to use is an aquarium pump purchased from any pet store or hydroponics supply shop and it is switched on and off at set intervals by a timer, which can be bought quite cheaply from a hardware store, hydro shop or even your local supermarket.
There is a second pipe that connects the grow bed to the reservoir called the return pipe. The return pipe is set higher in the grow bed so that when the nutrient solution reaches a certain level in the grow bed it flows back to the reservoir rather than letting it overflow onto the floor.
Let’s have a look at the whole flood and drain cycle in more detail so we can understand a little bit better how it all works. What you should bear in mind when you look at the flood and drain cycle is that plant roots need air as well as water and nutrients and optimum growth is achieved when the plant gets all three things in reasonably correct proportions.
Experimentation is the key to working out at what intervals the pump should run and it varies depending on the climate the system is operating in. Operating the pump for a duration of 15 minutes every two hours is a good starting point.
Diagram 1 shows the system in the aerating stage. The pump is off and any remaining nutrient solution is draining through the media back into the tank. The plant’s roots will likely still be moist but air will be present in the grow bed. This is the state that the hydroponics system will be in the majority of the time.
Diagram 2 shows the flow of nutrient solution into the grow bed when the timer switches the pump on.
Diagram 3 illustrates the flow of nutrient solution from the pump, into the grow bed and back into the reservoir through the return pipe. The return pipe protrudes into the grow bed and its position determines how much of the grow bed will be filled. About 5cm (2″) below the top of the media is a good level to fill the grow bed too.
Diagram 4 shows the end of the flooding cycle. The timer has switched the pump off and now the pump is not running the nutrient solution can flow back into the reservoir through the feed pipe and pump. It is important to not put a non-return valve into the feed pipe for this reason.
As the solution flows back into the reservoir it draws air into the media and the system commences aerating once again. The plant roots and the media will still be quite wet at this point.
How to Start Seedlings For Your Hydroponic System
Starting seedlings for hydroponics is easy and can be achieved with a minimal investment in time and money. You will need a tub of ice cream, a knife or scalpel, rockwool seedling cubes either cut from a slab or purchased already cut to size and of course some seeds of the plants you would like to grow.
For our example, we are going to germinate some capsicum seeds. The first step is to eat all of the ice creams and then wash the container thoroughly so it can be used to keep our rockwool moist.
Get Seedling Cubes
As previously mentioned you can buy rockwool seedling cubes that are precut like the one in our image to the right of this paragraph. It is more economical to purchase large rockwool slabs and cut slices off it to make your own seedling cubes however this is completely up to you to decide.
The seedling cubes should be soaked thoroughly in fresh water for a few hours and then rinsed prior to use to remove any built up salts from the manufacturing process and to make sure they are wet right through.
Seedling cubes already have holes in them but they are rather small and more suitable to cuttings. Use your knife to make the holes bigger in diameter and as deep as the planting depth specified on your seed packet for the plants you are growing.
Place Seed in Seedling Cubes
Place one seed into each hole in your seedling cubes. Once you have a seed in each hole of the seedling cubes gently place them into the ice cream container and fill it with plain water until it reaches about halfway up the rockwool seedling cube.
This will provide the initial moisture that will trigger the germination of the seed. Allow the water to evaporate to the point where the bottom of the ice cream container is only just covered and then top it up to halfway up the seedling cube if the seedlings have not germinated at this point.
Once your seedlings have germinated keep them moist with fresh water or fresh water and super thrive. Once the seedlings first set of leaves are open start watering them with 1/2 strength nutrient solution for a week or so or until they have become established and start growing.
Once they are well established you can start using full strength nutrient solution on them, making sure they remain moist. They can be planted in your hydroponics system at any time after they have become established and start growing however you may elect to keep them growing in the ice cream container until they are reasonably advanced.
Shopping List For Your DIY Hydroponics
The vast majority of the components required to build our DIY hydroponics system can be found at your local supermarket, plant nursery, pet store or hardware shop.
The plastic tubs, aquarium pump, timer, and plastic pipes are readily available however the inlet and outlet for the grow bed, nutrient and hydroponic media are best purchased from a hydroponics supply shop.
Heres the short version of the shopping list for the example system we have built but please be aware that your plastic tubs need not be the exact same size as ours. Please see the long version of the shopping list for further notes on the grow bed and reservoir.
The Short Version of the Shopping List
- 1 X 70 liters plastic tub for the reservoir
- 1 X 50 liters plastic tub for the grow bed
- 1 X 13mm grow bed inlet
- 1 X 19mm grow bed outlet with spacers
- 1 X aquarium pump (350-400lph)
- 24-hour timer
- 1 X 1m 13mm flexible plastic pipe
- 1 X 1m 19mm flexible plastic pipe
- Sufficient hydro-clay to fill the grow bed
- Hydroponic nutrient formula
The Long Version of the Shopping List for our DIY Hydroponics System
Growbed and Reservoir. Our DIY hydroponics system is based around two very ordinary plastic tubs that can be obtained from any number of different sources. They don’t even need to be new providing they are clean and haven’t been used to store chemicals or anything of that nature.
The tub intended to be the grow bed is 50 liters in capacity and the one intended to be the reservoir is 70 liters in capacity. These sizes are not functional for the most part, you could have 120 liters grow bed and a 120 liters reservoir if that is what’s available.
When selecting the tub for your grow bed tries to find one at least 20cm (about 8 inches) deep for your plants to develop good root systems however anything deeper than 30cm (1 foot) will be deeper than is necessary.
Having a grow bed that is deeper than necessary is not a bad thing, it just has no advantages and will require more nutrient solution to be pumped in before it will reach the plant’s roots.
Although our reservoir holds 70 liters it will only be filled to about the halfway mark, about 30-40 liters. This will provide a fair margin for the plants to drink and also to cover for evaporation losses.
Although our example grows bed is a 50 liters tub it will be filled with hydro-clay and not filled to the top with a nutrient solution during the flood cycle anyway, so it will only hold approximately 10-15 liters at the most. The rest is for buffering and to make sure the pump does not run dry.
Try to get a grow bed and reservoir combination that will allow the grow bed to sit on the top of the reservoir as ours does, it will save you time and money by not having to make a separate stand for the grow bed.
Grow bed Outlet
Grow bed Inlet and Outlet.
These nifty little gadgets are the inlet (right) and outlet (above) for the grow bed. You can improvise with a bit of pipe or garden hose if you want but for the sake of a few dollars buying the proper fittings is a wise investment.
They are very resistant to leaks as they seal against the bottom of the grow bed with a rubber o-ring, come with a screen to prevent the media blocking your feed or return pipes and are available to suit a variety of pipe sizes.
The inlet has a 13mm (1/2″) pipe fitting which matches the aquarium pump we are going to use. The outlet has a 19mm (3/4″) fitting, a larger diameter because the nutrient solution will return to the tank by gravity rather than under pressure.
You can also see that the inlet will pump directly into the bottom of the grow bed however we have purchased some optional spacers for the outlet to lift the level of the outlet screen to the high water mark of the grow bed.
Aquarium Pump and Timer.
The nutrient solution must be periodically pumped from the reservoir into the grow bed and an aquarium pump does this job extremely well. Our system uses a 500 liter per hour aquarium pump but its capacity is not really critical as long as it is capable of filling the grow bed reasonably quickly.
Consider that if your grow bed holds 100 liters of nutrient solution and you use a 100 liter per hour pump yet only flood your hydroponics system for 15 minutes at a time your grow bed will never get filled to more than 1/4 of its capacity.
There are DIY hydroponics system holds about 20 liters, is flooded for 15 minutes straight and the pump in that time will flow about 125 liters which promotes good cycling of nutrients during the flood cycle. Turning your pump on 8 times a day would rapidly become a pain in the behind so consider a timer a good investment.
There are many different types of media for use in hydroponics. The media takes the place of soil in your hydroponic garden and the type of media that you use can affect the productivity of your hydroponics system quite substantially.
Some hydroponic media such as perlite, vermiculite, peat moss, and cocoa fronds do not drain very quickly and are more suitable for passive hydroponic systems.
In an active hydroponics system such as our DIY flood and drain system where the nutrient solution is actively pumped into the grow bed at regular intervals fast draining gravel such as hydro-clay or scorier is a much better choice. Hydroclay is a great choice for beginners.
Hydroponic nutrient solutions are best purchased from your hydroponics supplier as ordinary garden fertilizers are not suitable for hydroponics. You can make an organic tea as an alternative to chemical nutrients however we would recommend that you start off with a store-bought nutrient solution until you get the hang of things.
The minimum that your reservoir will need is just a nutrient solution, these are usually two-part formulas that provide the nutrients that your plants need. They are usually available in a vegetative formula and a flowering formula, allowing you to control the exact ratio of the ingredients of the nutrient solution depending on the growth stage of your plants.
There are other goodies that you can also put into your reservoir such as buffering solutions and plant hormones though these are not necessary for good healthy plant growth. Some of them can markedly increase yields.