Hydroponics is the science of growing plants in a sterile medium.
For the roots to flourish in a hydro system, there must be adequate water, nutrients, and oxygen. One of the easiest ways to start with hydroponics is simply to submerge the roots in a light nutrient solution and provide air in the solution with a small motorized pump. When done correctly, this method also is one of the most productive, capable of turning your average pot plants into monster indoor trees!
Deep Water Culture: from start to finish
In this how-to article, I will give you the plans, a workable nute ratio, and a schedule to complete a grow with the bubbling buckets. This is what has worked for me as of late-- there will always be variables from one garden to another which will require minor adjustments.
These adjustments should be made gently! With DWC (deep water culture), the plants will react to any change much faster and the changes seem to affect the plants in a greater way. Your mileage will very depending on strain, lighting, nutes, etc. As for strain differences, it appears that no matter what the strain, there will be increased growth rates including the root mass! Therefore I would recommend that you maintain a sterile condition in both the buckets themselves as well as in the grow areas. Lack of diligence here will guarantee failure.
Selecting the bucket
This is a 3-gallon bucket that was found behind a hospital and previously contained fruit cocktail. Try to avoid any buckets which contained harmful chemicals, they may not come completely clean! Wash the bucket in a 10% bleach solution to ensure a sterile start. I also like to remove the handles. They’re still easily picked up without them and they did tend to get in the way when left on.
3-gallons should be considered the minimum for bringing a plant to harvest with 5-gallons or more being preferable. Larger plastic tubs like those from Rubbermaid can be used but special attention should be paid to reinforcing them-- they’re not meant to hold water. Double them up, one inside the other, or use a thicker container like a hydro reservoir.
Getting started with the lids
Cut the center of the lid out so a 6" net pot will drop in the opening. At the 3-o’clock position you will see a 1/4" hole towards the edge. That’s for the airline. The net pots are available at most hydro stores.
Buy the heaviest-duty ones you can find. The reason I suggest the 6" is for plant stability when larger. You will need it, trust me! If you do choose to use smaller net pots you must secure them to the bucket so the plant does not tip over.
Later you’ll see a bucket with three 3.5" net pots in the lid. This is great for starting seedlings or clones in! 1-gallon per plant vs 3-gallons so you’ll save on nutes and the number of buckets you have to change out.
Preventing unwanted growth
You have to block the light or the buckets will fill with algae, and fast! Algae will choke the roots of necessary oxygen-- growth will slow and the roots will turn brown. You must make it light tight!
I have used duct tape, but unless you used three wraps the light would still penetrate. I’ve since switched to using anti-corrosion pipe wrap tape purchased at a hardware store. The roll cost $8 and will cover four 3-gallon buckets and lids. It’s a vinyl tape that light can’t pentrate and sticks well.
“I prefer the dual-outlet pumps for two reasons”
First, you have the ability to run two buckets in the early stages. I’ve heard of people using gang valves and running four to six buckets off of one pump. This may or not work, I’m no expert on exactly how much O2 is required in the solution for a healthy root system and plant.
Second, I use a T so the dual outlet pump becomes a single outlet pump. I use one pump per bucket to insure plenty of O2 for the large root mass. At $30 it will last for many grows and pay for itself in time. What’s that equal to now, about 1 gr worth of product? Spend the money for a successful grow!
The airstone’s I prefer to use are the small ones . The reason being is the fine bubbles they produce. Fine bubbles supply the most O2 to the solution vs powerheads or surface disturbance methods. Buy a couple extra as this is probably the most vulnerable part in the system. I’ve tried one of the 6" Bubble Curtains and didn’t get as good of results. Also, there is a small lead fishing weight tied to the line at the stone to keep it on the bottom and in place. I’m sure I’ll catch hell for using lead!
Medium or mediumless clones? My preference is rockwool starter cubes and gro-rocks or geolite. You could experiment with aeroponic rooting and ignore the rockwool altogether.
Nutrients and General Hydro ratios
This section is where the most testing and variations will be done by others! I use the GH Flora Series 3-part nutes. I also use the Silica magic, silicon additve and epsom salt in the solution. I start with distilled water due to water quality from a well that might not even be good for human consumption. I have tried RO water with no bad experiences and do plan on installing a RO filtering system soon. Either way, the ppm of the starting water is near 0.
For seedlings and clones I use a 33% strength 1-1-1 solution. What I do is mix 1gal with 5ml Grow, 5ml Micro, and 5ml Bloom. Not in this order, as you have to add the micro first, but they list the solutions as G-M-B. I also add 5ml of Pro-Tekt and 1/4tsp of epsom salt. This goes into the bucket and an additional two gals of distilled are added.
10 drops of 70% Reagent Grade Nitric Acid bring the ph to 5.6 which is fine for me. I try and keep the ph in the 5.5-5.8 range and it will drift from the low 4s to the high 6s between changes depending on the plants useage of what nutes. For veg stage I use the same procedure for mixing to obtain the 33% solution strength. The difference being the ratio of the 3 parts. In veg stage I use the 3-2-1 mix which equals 15ml Grow, 10ml Micro and 5ml Bloom. The Pro-Tekt and epsom salt remain the same. Combine with 2 gals of distilled and adjust the ph to range.
For the flowering stage it’s the same routine and 33% solution strength. The ratio of the 3 parts are 5ml Grow, 10ml Micro and 15ml Bloom. The Pro-Tekt and epsom salt remain constant. Add two gals of distilled and adjust for ph range.
Keeping the water level
In my experience, the number one cause of failure was due to the nutrient levels maintained too high, at a level that allowed the rockwool cubes to contact the solution. What has worked well is to maintain the level about 1" above the bottom of the pot when using 6" net pots. In the triple 3.5" net pot buckets the level was about 1/2" above the bottom of the pot. There’s no reason for concern when the levels drop below this point. I’ve had the level drop to a point that it took 2gals to bring it up to par. The air roots most likely thrive when the level drops in the bucket.
For topping off the buckets I use the same solution as in the bucket at the same 33% solution strength. In the transition period from veg to flower I used a mix of 2-2-2 and in latter flower stages I have tried an aggressive formula of 0-2-4, both again at 33%.
This is the area that will see the most changes by others. Everyone has their opinion on which nutes are the best and others will consider organics only. The most problems in the future will be with organics… These will take considerable monitoring and pre-bubbling to break down the organic nutes.
Hope this has clarified the bubbling bucket for you. Get cracking and have fun!