In the beginning, you won’t need to replace the nutrient solution as frequently compared to when the plant has matured. How often you replace the nutrient solution depends. It could be every one to two weeks or longer.
Advanced top-feeding/dripping systems continuously trickle water over the young plant’s roots. After the plants’ roots have grown enough, some growers switch back to the original DWC set-up.
Cannabis DWC systems range in size. Some growers may place multiple plants in a single reservoir, while others may pump nutrients and oxygen into several small DWC reservoirs that hold one plant each.
This method is particularly effective due to the constant pumping of fresh nutrient solution. In addition, the lateral flow of this system can increase your roots’ health, growth rate, and yield.
In addition, the space between the pellets provides optimal airflow to prevent root rot when there’s not enough oxygen. Finally, hydroton exchanges cations (positive ions) with plants to improve nutrient uptake and pH regulation.
Hydroton clay pebbles are derived from an orange-red clay and look like brown balls with black spots. They are pH neutral (inert) and come in a variety of sizes to fit your specific needs. They are also pretty cheap and can be washed, dried, and reused for your next crop.
To set up your system, fill your reservoir with the properly mixed nutrient solution. In the beginning, when the plants are young, the nutrient solution will reach the bottom of the media.
Simply follow the included nutrient schedule or the custom nutrient schedules listed above (start at half strength and increase as needed) and keep the pH of your water between 5.5-6.5 at the plant roots for best results. Or feel free to use my custom DWC schedule for the GH trio [PDF].
Leaves color fading; lime-ish color:
This can mean that your plants are need more nutes, but more likely it means that the pH of your reservoir water is out of the desired range.
You can buy ‘beneficial bacteria’ to introduce to your reservoir. These bacteria will not only outcompete (and thus destroy) the bad bacteria, but it will form a symbiotic relationship with your plants and help them grow. Hydroguard works extremely well for this task, I can’t stress that enough!
Bubbleponics/Top-fed DWC is basically the same thing as DWC except for one small, but important, addition. A small stream of that same aerated, pH-balanced nutrient water is trickled over the young roots of your cannabis plants. This encourages the roots to grow faster and reach the reservoir water in less time, making for faster growth during the first part of the vegetative period.
557W PlatinumLED grow light hanging in my tent.
You can use an old five-gallon water jug as a container to mix your nutrients. You can use tap water, rain water or well water. Some growers use RO (Reverse Osmosis) water to grow cannabis since it has the least amount of extra ‘stuff’ in the water, though with RO you may want to supply your plants with a CaliMagic supplement to make up for the calcium and magnesium that’s normally found in most regular water sources. Either way, always make sure to “pH” your nutrient water before you pour it into the reservoir (see below).
You need to be able to keep your grow area in complete, uninterrupted darkness for 12 hours a day during the flowering period. Giving your plants even small bursts of light during their dark period can cause weird things to happen and none of them are fun. There are different advantages to setting your dark period for a certain part of the day (electricity cost, heat management), but it’s a good idea to plan your dark period around your schedule so you can make sure to see your plants while the lights are still on.
Important: Do not plug in anything just yet
Leaves turn brown on tips and edges; leaves curl down on tips:
Too much nutrients; change water and add less nutrients.