Deep water culture sounds like an exciting adventure, and it is - if you're enthusiastic about efficient methods of growing plants. As the term suggests, the plants grow in water.
Growing vegetables and other plants without soil is a process that has been around for centuries. Hydroponics is firmly rooted in the history of food production. DWC, as deep water culture is known, is a variation of hydroponics.
If you think about it, all plants need are air, water, nutrients, and light to grow. It's been proven that plants grown using the DWC method grow faster and produce higher yields than plants grown in any type of soil or climate.
Interested? Discover how you can set up your own deep water culture at home without too much effort or outlay.
So, Why Is It Called Deep Water Culture?
Unlike other hydroponics methods (such as the ebb and flow system), with DWC, most of the root mass is submerged constantly in water. The plant itself is in a relatively large (or deep) body of water. These two aspects have earned the method the name of deep water culture.
It's interesting to note that the larger the reservoir, the greater the stability in the nutrient solution, with fewer variations in its pH value. This translates into less maintenance and monitoring, topics that we'll get to later.
DWC is one of the simplest methods of hydroponic growing, and it's easy to set up a small system at home. And you don't need to have experience: just try it!
There're complete kits available online that are easy to assemble. They provide you with all the essentials for your deep water culture system.
● a five-gallon bucket
● one or several plant baskets, which fit into holes in the bucket lid
● an air pump, in the 44 gallons per hour (GPH) range
● air tubing
● an air stone
● growing medium
If you're a DIY kind of person, then you might have a few things lying around the house which will do the job equally well. If you once had a small fish tank or aquarium, you could probably use the air pump from that for your DWC system, for example. And, of course, the small fish tank could serve as your reservoir.
Well-aerated water assists in the delivery of nutrients to the plant's roots. Despite encouraging DIY enthusiasts to use what resources are to hand, we recommend that you have a spare air pump to hand just in case your existing one fails for any reason.
The main thing to remember is your plants need aerated water for the transmission of oxygen to the plant's roots, and nutrients. The type of plant nutrients you need will depend on what you're growing. Again, there's a range of purchase options available online.
Other Things You'll Need
● A thermometer
● pH testing kit
Most plants are happiest in water temperatures ranging from 62-68°F (17-20°C). If the water/nutrient solution temperature goes above 72°F (21°C) the dissolved oxygen (DO) level goes too low. This places stress on the plant.
Plants take temperatures below 60°F (16°C) as a signal that the season is changing and start to slow their metabolism, which in the growth phase would lead to slower growth. If you're experienced, you can manipulate the temperature of the nutrient solution near the flowering stage to hasten ripening. Our advice is to keep the temperature constant, and let the plants do their thing!
Cheap and reliable pH testing kits are also available online. Anything between a pH of 5.5 and 6.5 is fine. Vegetative growth responds best when the pH is between 6.0 and 6.3. Flowering and fruiting prefer a pH of between 5.7 and 5.9.
By monitoring and adjusting the pH levels of your nutrient solution as necessary, you'll be ensuring optimum availability of the minerals and nutrients that the plant needs at each stage of its development.
Keep the EC/TDS on the low side. (That's electrical conductivity and total dissolved solids for the uninitiated.) Based on the manufacturer's guidelines, try half-strength or even lower at first, when the plants are young.
Lower EC normally results in a higher intake of water by the plant, thus increasing the plant metabolic rate and therefore the transport of nutrients.
If you want to get geeky, then you can read all about whether EC or TDS is the more reliable measurement when determining the strength of the hydroponic solution. For beginners, simplicity is best!
The Plant Basket
Traditional flower pots should not be used since they only have one tiny hole through which the roots can pass. What you need is a plant basket, with ample room for roots to spread out in all directions. Watching the root mass grow is perhaps more fascinating than watching the top half of your plant develop.
A healthy root system indicates that your plant is doing well. If the roots begin to look dull or brownish, then something (usually temperature or pH) isn't right, and you should take steps to remedy the situation.
If you have multiple plant baskets in the same reservoir, or a modular system, ensure that the plant baskets are spaced sufficiently far apart so that each plant has enough room to grow. There's no real rule of thumb here since each plant is different.
The Air Stone - Avoid Root Void
Aside from the air pump and the plant nutrients, the air stone is a very important element. It's worth making sure you get a good quality one since this is the piece of equipment that regulates the bubbles caused by the air pump. It also distributes the air bubbles evenly throughout your reservoir, meaning that all parts of the root system get adequate oxygen and nutrients.
You must avoid root void – an area of your reservoir that isn't properly aerated, causing some parts of a plant's root system to get less than ideal levels of oxygen and nutrients, and begin to die.
Benefits of Hydroponic Growing
Although it might seem complicated, DWC is very low maintenance. The system has only a few moving parts. Once you've had success with a single-bucket system, you might want to upgrade to a bigger system – or simply create more single bucket systems.
There are reports that lettuce takes only 30 days to matures in a DWC, compared to the 60 days typically required in soil. The same is true of other plants, like cannabis. Deep water culture is immensely satisfying because you can see your plants growing rapidly from day-to-day.
You might want to keep a DWC logbook or diary. As you progress, your notes could be a useful resource on which you can base improvements in the way you grow things in the future. You can also use your notes to share info in the Grobo online community discussion group.
Disadvantages of Deep Water Culture
Most problems with deep water culture can be avoided. In small systems - such as the five-gallon bucket system, you might have wild fluctuations of pH, water level, and nutrient concentration. This is because it's very easy to over- or under-calibrate with small systems.
Pump failure or electricity outage for any length of time could cause your plants to "drown." If you have an electricity outage or a pump failure, your roots may struggle to survive in the low-oxygen nutrient solution. It can be difficult to maintain consistent water temperature in DWC as well if electrical lighting needs to be your chief source of heat.
Maintenance and Monitoring
Aside from monitoring water temperature, and testing the pH of the water, you'll also need to check the water level.
Remember that the plants are growing. The faster they grow, the greater the uptake of water (and nutrients). Their root mass needs to be covered at all times. The success of your DWC experiment depends on maintaining a constant water level which covers the root systems adequately.
Dealing With Pests
All plants attract bugs, and this is a vast topic that depends on what you're growing and the micro-climatic conditions you have created with your deep water culture system. We recommend you take the organic route whenever possible when dealing with pests due to the proximity of the nutrient solution to the pesticide. In other words, with DWC you could kill the pests, but you might kill your plants too.
Checking for bugs is part of daily care and monitoring Spotting bugs early is the best pest control there is – whether we're talking about a single-bucket DWC or vast fields in the middle of the prairie.
If you're planning to grow cannabis using the deepwater culture method, then to get the best yield, it's best to read up on all the pests cannabis is susceptible to, and that can potentially damage your crop.
The Beauty of DWC
Many of us live in the city. We don't have access to even a small patch of land where we can develop a small garden. Deep water culture offers us the opportunity to cultivate something and reap the rewards in a very small space indoors.
Some gardeners have special greenhouses for their hydroponic projects, but a corner of a room in your apartment is more than enough to get started.
Higher yields and simplicity are two of the best reasons to switch over to deep water culture.
We're big on encouraging people to grow things for themselves, even if they don't think they have green thumbs. Check out our other options here.