Introduction: DWC Hydroponics
DWC hydroponics is a very efficient system while being extremely beginner friendly. Parts cost is quite low and the system easily scales in size.
This is a very basic overview of DWC hydroponics but is a system that can easily be expanded or reduced to suit your growing needs. Personally I wanted a system that would provide fresh greens all winter long while requiring very little human intervention. As it currently stands this system has fully automatic lighting and irrigation (mechanical timer based), the only aspect I need to be involved with is the initial seed planting and water changes. After that its simply a waiting game until harvest :).
In the video below I will go thru all aspects of my system which should answer all of the major questions regarding DWC hydroponic growing.
Once you've made your way thru the video I've also included a small Tips/Tricks list in the following pages to help clear up the confusion a beginner will encounter when moving into the field of hydroponic growing.
Enjoy, and many thanks!
Step 1: The Basics Answered
There are 3 major aspects to a hydroponic system: Light, Water and Air. Here I will briefly explain the way to setup your system to make best use of these 3 elements.
For your first system stick with fluorescent light fixtures (color temp of ~5000K to 6000K for vegetative growing), or CFL based bulbs. These are cheap, readily available and safe. Keep the lights on for about 18Hr / Day followed by a 6 Hr dark period. Plants that bloom or run thru a fruiting cycle (tomatoes) will tax fluorescent systems but will still grow, just not as well as they could with more powerful lighting options. If your wanting to grow larger more nutrient hungry plants a nice value to shoot for is about 50W/sq ft. of lighting, vegetative crops (like herbs and lettuce) can usually grow with far less light then that. Once your feet are wet with cheap lighting systems then look into more powerful setups such as high pressure sodium bulbs, and mercury-halide lamps. These are HID style lights and produce many more lumens per watt but also come with a higher price tag as well as operating costs. LED's are an option but are even more expensive when compare to the lumens/watt of conventional HID lighting. Light color as well as light duration also play more of a part in plants that bear fruit so we will not get into that with this guide.
Right from the get go I strongly suggest going with R.O (reverse osmosis) water. This will not only ensure you have little to no chlorine in your water, it will also ensure that your ppm ratios for dissolved solids is very low. Chlorine in tap water can be worked around fairly easily, and the pH can be adjusted, but for the raw rookie going with simple R.O water from your supermarket is going to help produce positive results without needing to invest in expensive testing gear. The absolute best option is to use rain water in your hydroponic system (assuming your in an area where acid rain isn't a common occurrence). Keep the water in your system at room temperature and keep your mitts out of the water tanks! Tanks should also be dark to reduce light transmission and keep algae growth to a minimum.
Get yourself a cheap aquarium pump. On most hydro systems the water pressure your dealing with against the airstone is relatively low when comparing it to an aquarium they are designed for. Air volume is of slightly more importance, but most small hydro systems won't need more air then even the smallest pumps can provide. If you have some extra cash to burn and are building a system larger then ~5gal. go with a dual output pump. If your pockets run deep this is the one aspect of the DWC system you really can't overdo, bubbles are good. In other words you really cant provide your plant with too much air...within reason.
Clean clean clean! Anything you put into your system needs to be clean. The plastic containers that I used had a very slight film of oil on them from the molding procedures at the factory. Wash everything with hot tap water (I'd leave soap out of the equation). Anything that needs disinfecting can be cleaned with a solution of hydrogen peroxide and water. You can sterilize your grow media with this peroxide solution when they start looking a little dirty (obviously not during growing)! Anything that is porous (the cotton balls in my setup) must be thrown out after growing as they will harbor evil that can make its way into future plants...thankfully cotton balls are CHEAP!
Step 2: Conclusion...
With everything working happily you should see your plants (lettuce in this case) sprout and begin grow early in the first week. From here on in I simply keep the nutrient bath fresh (replace every 2 weeks) and watch the plants grow!
Hydroponics is a incredibly vast hobby to get into and this guide just scratches the surface of DWC growth, let alone the many other methods of soil-less growing. What I have outlined is a system that should yield modest repeatable results but it by no means is a polished or exacting science. Stacking the odds in your favour is what I planned to do with this guide. I've seen people run working hydro systems using plain old tap water, the cheapest store bought gravel and a couple handfuls of general garden fertilizer from the home store...in other words if you want to try your hand at a system don't fear failure! Plants have a way of adapting and overcoming that may surprise you, it continually surprises me!
Many thanks and please check in on my video channel, I will continue to post updates on what I am working on and how the plants are doing.
Step 3: Update #1 - Week 3
Well it has been 2 to 3 weeks and as you can probably tell from the picture, I could not leave the system well enough alone :). Since my last video update I have broken the system down into to a DWC system (with a different lid, more on that shortly) and an Ebb and Flow bucket (which used the original small irrigation pump). I've also build a more powerful CFL lighting system (I want to grow tomatoes and peppers which grow best with more light) and contained the whole system in a home made reflective fabric wardrobe.
Here are the lessons I have learned thus far:
Lesson 1 - Light Leaks
Party cups let far to much light down into the tanks! I am sure I could have simply covered the tops of the cups with aluminum foil with a small hole for the plant but wheres the fun in that! The cups were acting as light pipes and after a week I had some pretty solid algae growth in the tanks. My newest DWC tank has a white dibond top to help reflect some light, and uses 2" net pots spaced much closer together. I've also 3D printed grey disks that sit ontop of the growing media to help stop light penetration into the tanks, once again alum foil would work fine...but I like to overcomplicate system fixes ;).
Lesson 2 - Net Pot Size
Use smaller growing pots. The party cups were working just fine but required the plant to grow its roots much longer to reach into the water bath. This is fine, and once again was growing my food perfectly well but net pots are cheap and once I was on the other side of town I grabbed some. If your unable to get small net pots the solo cups will work fine, just make sure to lightproof them much better then I did.
Lesson 3 - Cotton Balls
These worked just fine, the tend to shred apart over time and get stuck on the hydroton rocks but otherwise worked perfect. Roots grew thru them and seedlings were able to push their way out of them. When I went to purchase the net pots I ended up buying some rockswool cubes to start my plants in but there is no reason you could not use cotton balls as I initially did...after all the plants only really require the cotton to get roots established, from there they will wrap around the hydroton and work down into the nutrient tanks.
Lesson 4 - Clean Everything
Although I stressed this in my initial post I did not carry it out properly when I switched systems. It took 3 days for algae growth and bacteria to completely engulf my new system. The tanks started to really smell off and the water began to foam from the air stones.
I pulled all the plants from the system and flushed out each cup/netpot with 1L of water with 2 teaspoons of hydrogen peroxide (I wanted to sanitize the plants roots without killing them). I let the plants sit for a few minutes, then flushed with a few cups of plain tap water. The tanks were dumped and sanitized with a bleach solution, I believe I used 2 tablespoons of bleach for 10 litres of water. I scrubbed all nooks of the tanks, the air lines/stones and the underwater pump. I then left the bleach solution in the tanks for 10 to 15 minutes. After that everything was rinsed with plenty of tap water and everything was replaced (RO water in the tanks, add nutrients, add plants, etc.)
Once back up and running there were no smells and the DWC tank is totally foam and algae free (right now I am sitting at 12 days after refilling the tanks with nutrients).
I will get a video posted shortly of the new system but as it stands right now its running happy and producing some excellent growth. The 3 large lettuce plants will probably be moved over to the Ebb and Flow system in the next week or so as they are very quickly growing over my other plants! Lettuce in a DWC system grows scary fast, fast enough to see a difference in 6-10 hours! The additional light from my custom CLF hood (6-23W 6500K lights) reduced the plants tendency to "stretch" and is going to be of much use when the peppers go into their bloom cycle. The light is a little overkill for the lettuce, spinach and basil but it keeps the plants short and fat. I have another batch of seedlings slowly sprouting which will fill the empty voids once the lettuce plants move to the Ebb and Flow system. All in all I am once again completely blown away buy the simplicity and ease of a well setup hydroponic system. At this stage its a complete hands off system for 7 days (the plants drink enough in that time that I need to refill the nutrient tanks with RO water) otherwise they could go the full 2 weeks between water changes completely hands off!
Step 4: Update #2 - Week 6
Now we're growing!
Here's the latest pictures of my active system (the uploaded video below was taken approx 1.5 weeks before these photo's). The pictures above show how I have thinned out my tomatoes (removed all but the 2 strongest growers). I have also harvested 1 complete basil plant, and pulled another from the system as it was not growing as strongly as its neighbour. The strongest basil plant had a cutting taken from it ~1 week ago and seems to be rooting nicely inside the rockswool cube. I have started sprouting 4 more basil plants but I am hoping my cutting will establish strong roots in the next few weeks and give me a jump start (growing from seed is slow).
Once again I have learned many new things since the last update that are slowly letting me get the most from my hydroponic system. I will quickly summarize these points.
Lesson 1 - Organic Growing in DWC Systems
Apparently the success when using organic nutrients in a DWC system is low. The nature of organic nutrients means the break down over time and create a sludge (something I have mistaken in the past as algae growth from light leaks). This sludge can plug up air stones and bring about root related problems easier. To get around this you need to provide LOTS of bubbles and keep the nutrient tank temperatures low. I have been having great success with this system so its defiantly do-able and still a route I would suggest for a system of my size...I would not go any smaller then ~10L for a DWC system. The ebb and flow system works just fine with organics and has far less upkeep...does not grow quite as explosively as DWC but much easier to tend too.
Lesson 2 - pH and PPM
When I first started off growing I was always checking pH and was looking into getting a PPM meter to measure my concentrations. This is defiantly a very good path to go down when using sterile chemical based nutrients...in organics its a bit more of a "shoot from the hip" style of growing. My tanks will swing in pH as the nutrients break down and get absorbed by the plants, apparently this is quite a bit more severe then in chem based systems and most say to just let the system do what it wants. In chem based systems pH swings are usually due to nutrient uptake in different proportions to water uptake and as such can be controlled easily. Organics are a different kettle of fish and I'm still learning how best to deal with it. I've also been reading that PPM values can be different in organics due to additional trace elements not found in chem based nutrients. The more you read about this online the more you confused you will become...lets just say everyone seems to have a different take on organic hydroponic systems and it seems to be a pretty polarizing area of study.
Lesson 3 - Pruning and Taking Cuttings
This is a very easy thing to do so long as you do it correctly. When taking leaves off my basil plant I simply pinch the leaf off as close to the main stem as I can. Be sure your hands are somewhat clean and do not tear or pluck the leaves off, a pinch helps to crush the remaining steam closed and helps the plant seal off the cut. Only take a little from each plant, its a high stress situation for a plant and its going to need a few days to properly repair itself and channel its energy back into foliage production.
When taking a cutting use a clean razor blade ( I used a brand new single edge razor blade cleaned with alcohol). Take a slice as close the main steam as you can at a hard angle (~45 degrees). This will maximize the space for roots to start on the cutting. Its also good practice to slit the steam of your cutting to increase root space. Be sure to take a strong cutting with a few leaf nodes as the plant is going to need to draw all its energy (and water) from its foliage for a few weeks until its roots are established enough. Keep your cutting moist (remember only the leaves will take in moisture at first, there are no roots)! Feed only water or very very week nutrient solution until roots develop. There are many guide online regarding this topic so I will not go into further detail.
Lesson 4 - Keep Plants Moist
All my plants seem to like a nice misting now and then from a spray bottle (just plain RO water, both top and bottom of leaves). This helps to keep the leaf pores free from dust and ready to absorb C02...plus its relaxing for the grower as well :). A misting right when the lights go out gives the plants some time to draw in the moisture and helps mimic nature (very rarely do you get blazing sun and rain at the same time). Misting also helps to wash away any bugs/pests that might want to nest on your plants (although it was -40C here the other day so bugs are in short supply).
As always thanks for watching/reading and I will continue to update as my grow progresses!
Participated in the
Hydroponics and Indoor Gardening Contest