Understanding Deep Water Culture and Feeding
Deep water culture (DWC) is emerging as the hydroponic system of choice for cannabis growers because of its fast results and reduced labor. Follow Dan Vaillancourt’s guide to DWC to see if it’s the right method for you.
Deep water culture (DWC) is a low maintenance, fast-growing method of hydroponics. In this type of system plants sit in net pots with roots suspended in the grow chambers nutrient solution while aerated water recirculates throughout the growing system.
If you have ever heard the phrase “look at your roots, not your fruits,” then you may understand why growing in this style of hydroponics can be very lucrative. When your plants’ roots have little to no resistance to push against, combined with proper temperature, oxygen, and nutrients, it’s easy to see the incredibly fast, lush growth above the root base that DWC is famous for.
Going Deep with Deep Water Culture
The reason it is called “deep” is because of the small air bubbles that travel up and through the water from your air stone at the bottom of the tank. As these air bubbles travel upward they spin, gathering more oxygen in this process and releasing it into your water, increasing your overall dissolved oxygen levels, making deeper water work better for this method.
Higher water volumes in your overall system will also result in less pH and fewer temperature and PPM fluctuations, making the deep aspect of this growing system and the combined grow chambers useful for a smaller fertigation room feed tank. Utilizing the grow chambers’ water volume allows you to have a small controller tank and a compact fertigation room depending on the number of plants you have.
Fast Feeders in DWC
Deep water culture hydroponic systems have immediate access to all the nutrients they need at any given moment, making them easy to overfeed if it’s not done right.
Maintaining a low PPM of nutrient strength and only raising at peak flowering periods, coupled with regular flushing, is ideal with DWC because this will keep your plants from getting too many nutrients, which can cause problems.
If you notice tip burn, where the tips of the leaves turn slightly yellow, or burnt and crisp in later stages, then you have added too many nutrients. Prior to this, the plants will likely be a very deep green in color. Ideally you want the plants to be vibrant green, not too pale, and not too dark green.
Tip burn is only the visible sign of too much nitrogen. An excess of other nutrients will look different, depending on which nutrient is overabundant.
Ideal nutrient levels differ based on the strain, type of nutrients added, stage of growth, light intensity, and CO2 levels, so unfortunately there is no silver-bullet formula. But these variables dictate the optimum levels your nutrients and additives should be at each week throughout the growing stages.
DWC is Less Labor and Environmentally Friendlier
Water consumption, nutrients, and labor are all much lower with DWC. This is because a drain-to-waste system will waste the nutrients you feed them each day, whereas a DWC system recirculates the water and it is swapped out once weekly. This accounts for at least 90 percent savings in water and nutrients and cuts back drastically on labor needed in filling tanks and mixing nutrients regularly.
This growing method is a favorite for hydroponic gardeners in areas prone to power outages. In the case of an outage the growing system does not dry out or overfill. Instead, the recirculation and aeration will stop (along with the other equipment), however, oxygen remains in your solution for roughly 48 hours, which is generally within the time an outage will be fixed.
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Although this growing method is the safest in the event of a power loss, we still recommend exchanging the nutrient solution for a fresh one once power is back on. Cleanliness is very important in recirculating hydroponics methods.
Once a week, 29 percent hydrogen peroxide should be added to plain, pH-adjusted water and run through the system for 12-24 hours. This will clean your tanks, piping, and root base while adding oxygen to the roots. This should be applied at a rate of 3 milliliters per gallon.
Plants leaves will perk up during hydrogen peroxide flushes and flowers will swell due to the added oxygen making this tip both useful for a clean system and good growth.
Maximum Yield with Deep Water Culture
Licensed for a certain number of plants? Out of all the types of hydroponic systems, DWC is one of the best for utilizing your plant count and making the most of it with its ability for large, bushy growth. Filling large areas with very few plants is easy with DWC.
As amazing a system as DWC is, it is not right for every scenario. The large bush-style growth does mean you will have to keep them in the vegetative state for longer (two to four weeks), so a larger vegetative room is needed. Water chillers will also be required to maintain a correct water temperature due to the water passing through the warm growroom pipes.
If vegetative space is low, water or nutrient consumption is not of big concern. If you want to throw a grow system together faster, an automated stonewool or coconut husk drain-to-waste hydroponic system may be more up your alley.
Although DWC can cater to the low-plant-count grower and produce large bushes, it can also be designed closer together and focus on top flowers. Proper growroom design and fertigation planning is crucial to a successful deep water culture system.
There is no growing method quite like a fully automated DWC system. The level of control you have over your roots offers the healthiest, fastest growing plants possible. Hopefully this basic understanding of DWC will help you choose the best growing system for your needs.