Hydroponic and coco cannabis growing
Growing cannabis in a hydroponic system is much more simple than it may sound. Growers using a hydroponic system experience extra vigor, less bugs, and done right - they have the opportunity to "flush" their plants more thorough than any soil medium would ever allow.
Hydroponic growing basically consists of suspending your plants in a neutral medium such as coco coir, clay balls (hydroton), or any created neutral well draining medium and regularly running and recycling a liquid a water and fertilizer mix through that medium and back into your reservoir.
​
Some essential tools you will need for hydroponic growing are:
-
EC/PPM (Electric conductivity) Meter.
-
Ph Meter/litmus paper
C
There is no "best" system to use for growing hydroponically, They all grow cannabis great, and all have to potential to grow the best, and worst cannabis you have ever seen.
Each system comes with its special way to use it optimally, how ever they all basically fall under the same concept when it comes to feeding/fertilizing your plants.
Growing in Coco
Coco coir is easily your most basic transfer to hydroponics from soil growing. Coco is a versatile growing medium that has benefits for many different types of growers. It can be used by itself as a growing medium in conjunction with bottled fertilizers, or it can be mixed with soil (or a supersoil in place of potting mix) to help fix compaction and loosen the soil. One of the most suitable ways to use coco coir for cannabis (in my opinion) is to mix pure coco coir with about 30% of an airy amendment like perlite, and provide nutrients through the water. This creates an amazing environment for cannabis roots to thrive. Note: most bagged coco will come already premixed with perlite so there is no need for this step.
Always flush your coco and allow to run off before planting.
Growing in coco can be as basic as growing as you may have been growing in soils - with maybe more regular watering. A seedling may be raised in coco alone for the first 2 to 3 weeks without the need for any fertilizers, just water.
-
Check your tap waters pH, cannabis likes a neutral pH anywhere between 6 and 7, and most tap waters are generally fine without needing adjusted however it always pays to check. An unbalanced pH throws off the uptake of certain key nutrients and can have you hunting for ghost nutrient deficiencies that are only present because your pH is out.
-
Choose a fertilizer range you wish to grow with. There are many to choose from, and all work great in their own respect. Over time, you will find a fertilizer range that suits your growing style.
From personal experience there are two fertilizer ranges that you cant go wrong with - any grower can use these and as long as instructions are followed they will have no issues at all. the Two ranges I highly recommend are:
House and Garden and Canna ranges. -
​
There are many other fertilizer ranges that work just as good as the above such as - Nutrifield, BudZilla, Advanced Nutrients and many more. the range in different prices and applications. What ever you choose, it is important to follow the guidelines on the bottle. to sucessfully do this, you will need an EC (electric conductivity meter).
EC meters come in a few different forms, and can be super expensive. Blue Labs make the best equipment, I cant fault them for accuracy. They offer digital EC and Ph meters combined, or if your budget is lower, their EC truncheon is just as accurate at about a 5th of the price - that, and some pH paper and you are set!
As a general rule of thumb, I have personally found there is no need to go overboard with your fertilizers when growing cannabis hydroponically or in coco, each strain will have its quirks on how much or how little fert it likes.
There is sweet spots to find on your EC meter when it comes to ferting that any strain seems to like. let your strains tell you whether to go any higher - trying to pump them with too much is going to begin effecting end results from yield to flavour.
EC/PPM Sweet spots.
-
Seedling to 30cm tall - EC 0 to 0.8 (0 to 800ppm)
-
Established plant 30cm to as tall and bushy as needed - EC 0.8 to 1.5 (800 to 1500ppm)
-
Flowering weeks 1 to 4 - EC 1.3 to 1.6 (1300 to 1600ppm)
-
Flowering weeks 4 to 12+ - EC 1.6 to 2.2 (1600 to 2200ppm)
The addition of heading formulas for example PK 13/14 or shooting powder may require you to set your EC/PPM at a lower level than described above before adding, they may also bump the EC/PPM up higher than any reading I gave above, Follow the instructions for each individual product on the products packet and you generally cant go too wrong.
Heading formulas are fantastic, and do bump up the yields, these are fine to use - even more so than growing in soil because with hydroponics and coco you can flush!
FLUSHING:
The joys of growing in coco or a hydro system is being able to thoroughly flush growing your plants ONLY in water for the last 2 weeks at a minimum and experiencing the true flavors of your strain in the cleanest possible way.
The last 2 to 4 weeks, flag ANY ferts... fill your reservoirs or bottles up with ONLY water (pH'd if needed) and finish the plants in that only, The taste is amazing.
Other hydroponic systems
There are many other ways to grow hydroponically. Apart from setting up what can sometimes be complex system, hydroponic growing can be a certain walk in the park with most premade systems having basic automation built in so apart from mixing and filling a reservoir - watering and feeding of your plants is done automatically allowing you to focus more attention to your canopy. The keys to the inner workings of most hydro systems:
-
Oxygen is the biggest key here. - The reason why hydroponic systems grow plants with more vigor and yield is because the roots have direct access to oxygen. You can improve roots access to oxygen by: irstones in your reservoir airating the water being feed to your plants, and by your choice in medium ie hydroton, rockwool, coco, perlite, vermiculite.
-
How you store the water feeding the plants in your reservoir. - You dont want to shock your plants by giving them a cold dose of water every 30 minutes everyday... So having a water heater to keep the water warm answers that. Your optimum water temperature is 25 degrees Celsius.
-
Clean and sterile equipment. Huge key here. To put it simply, plants will be at their happiest, and easiest to care for in a system that is clean and sterile. The best way to remain as clean as possible is changing the water in your reservoir at least once a week... no more than 2 weeks. Thoroughly clean, and sterilize and add in new fresh water/fert. After every grow cycle (seed to harvest) Remove all equipment and sterilize thoroughly to give your next grow its best chances.
DWC GROWING
DWC (Deep water culture) is a really simple way to set up a basic hydroponic system to grow 1 to 6 pet plants dependent on size.
As the pictures above demonstrate, a DWC system can simply consist of:
-
A plastic tub (preferably not clear) or bucket with a lid
-
Your choice of number of plant nets go in the top. (Big plants - just go with one, small - go with upto 6 on a 60litre tub and lid). Fill plant nets with clay balls.
-
An air pump with air stone and ideally a non return valve on that air pipe.
-
A water heater, needed especially for winter months, to keep the water at 22 to 26 degrees celcius
BOOM you have yourself a hydro system! When first establishing plants in the system and roots are yet to dangle into the water/fert. it is a good idea to dip your net plant in the nutrient solution at least twice a day for the first 5 to 7 days until roots start hanging down.
DWC (Deep water culture) is a really great way to harvest some seriously clean roots for those interested in making topical root balms, poultices and medicines.
BUCKET/BUDDY HYDROSYSTEMS
BU
Bucket/buddy systems are fast becoming popular in commercial and home hobby growers choice of systems.
There are many different forms of this system available but generally they fall under one of two categories:
Flow to waste irrigation:
Flow-to-waste drains solution out of the system and away—forever. This option is more wasteful, but much simpler in terms of nutrient balancing.
What is nutrient balancing? Well, depending on the crop and its age, plants will take up unique ratios of nutrients. Younger plants of one crop might take up more nitrogen than older plants. Plants that are growing fruit might take up more phosphorus, etc.
Even though fertilizers are formulated to fit the crop, there are still minute differences in the ratio of nutrient to nutrient in the fertilizer and the ratio of nutrient to nutrient that the plants use. This means that over time, a solution can become unbalanced; one nutrient may accumulate while others are used up. This can lead to deficiencies and (less often) toxicities.
This makes flow-to-waste the simplest drainage technique
​
Recirculating irrigation
The more conservative drainage option is to run your buckets on a recirculating system. In a recirculating system, the buckets are irrigated and drain into a return line, a PVC line at a tilt that brings water back to the reservoir for reuse.
Growers using recirculating systems can avoid nutrient imbalance by replacing the water every few weeks (this saves water and nutrients, and cast-off water can be used for other garden beds) or by balancing nutrients individually.
Balancing water nutrients individually involves getting a periodic water analysis to determine the levels of each element in the water.
Once low nutrients are identified, growers can adjust nutrients individually. This entails using a multiple part solution (some growers have solutions with as many as 11 parts) and can get quite complicated. I don’t recommend doing this without taking a course on nutrients!
NFT SYSTEMS
​
​
NFT (Nutrient Film Technique) one of the most popular hydroponic systems of the 90's and early 2000's. The system that comes to most people minds when it comes to hydroponics, the long PVC gullies or tubes hosting great numbers of plants suspended in net pots. In the horticulture industry these systems are seen growing mainly lettuces and strawberries, however with the right techniques - these systems can grow anything.
As the picture above might suggest - cannabis in an NFT system is best kept at low heights - "sea of green"(SOG) style. Allowing for minimal to no veg time, and flowering almost instantly.
​
Although the hydro in hydroponics stands for water, providing air to the plants’ roots is just as important a part of the process. NFT systems provide air to the roots by exposing most of the root mass to the air permanently.
How it works is that your plants are grown in long channels (sometimes referred to as troughs) with net pots or neoprene collars to hold them in place. A thin film of nutrient solution is continually recirculated along the bottom of the trough, providing food directly to the plants. The bare root mass between the suspended plant and the film of nutrients at the bottom of the channel is kept out of the solution and exposed to the air.
The 3 most important factors to consider when building a NFT system to grow cannabis are:
GRADIENT/SLOPE -
It is super important to build enough of a slope downwards in the gullies in order to stop water pooling.
FLOW RATE -
-
As the name suggests, the system only requires a thin film of nutrient solution to work effectively. Run it too deep and you are defeating the purpose, too thin and there will not be enough nutrients available to your plants. Flow rate is obviously a result of the gradient and pump and, as a consequence, will be specific to your own individual set up;
-
As a rule of thumb a rate of 1 liter per minute should be your target flow rate. When introducing new plants to the system you may need to reduce this to around 500ml per minute. At the other extreme, an upper limit of 2 liters per minute should be adhered to. Flow rates out of these limits may cause nutrient uptake issues.
​
LENGTH OF GULLY/CHANNEL -
This generally only applies to those more commercial sized setups.
Again oxygen comes into play here, growers (just as in other systems) use reservoirs to oxygenate the water. In NFT systems, A Gully that is too long may result in depletion of that oxygen in the water by the time it reaches the end of its run. As a rule of thumb, anyone using an NFT system should not allow their gullies to be longer than 10 to 12 meters.
Hydroponics is a great hobby to get into, and once you have your system dialed in, it is actually an easier way to grow. Remember to flush at the end, and enjoy some of the cleanest cannabis to grace your endocannabinoid system.