Sharing some things I have learned doing Deep Water Culture with cannabis.
Technically what I use is called “Bubbleponics”. First your environmental needs must be met - light, temperature, humidity and air movement all need to be in range for plants to grow well. I will assume you understand these basic concepts. The rules for a good DWC are simple but not very forgiving. Plants respond adversely quickly to something out of range. The good thing is that they will also respond well to a correction quickly. DWC is an everyday task; in fact checking your plants many times a day can keep you ahead of needs.
Two tools that you cannot do without are a good PH meter and a EC meter; both should be equipped with a temperature gauge as well. Maintain them and replace them on the vendor’s schedule.
The five basic components:
1. Water. You could spend a lifetime trying to learn about water for plant growth but let’s keep it simple. Most people can use their tap water as long as the beginning PPM is 200 or less. If your water goes over this you will need to mix it with distilled or Reverse Osmosis water to get it below 200 PPM. Use a float valve and top off bucket to keep the water level in your reservoir consistent even small fluctuations can cause stress. Set the water level 1” – ½” below the bottom of your net pot. Aerate your water for a day or two before you intend to use it. This will help precipitate calcium carbonate out of the water and make it easier to control your PH. I just use my top off tank for this. The perfect reservoir water temperature is 68°F. This is the temperature that water holds the most dissolved oxygen. Do not use copper, brass or aluminum anywhere in your system; not even the tiniest fitting.
2. Air. Roots need air. An aquarium air pump and air stones provide this critical component. I always use two pump/stone combos for redundancy. Losing aeration even for a short period can be problematic. The smaller the bubbles are coming out of the stones the better. I use a UPS battery back-up on my air pumps. The volume of airflow needs to be high enough to saturate the water but not be so violent that the roots are damaged. Smaller bubbles allow more airflow with less violence.
3. Nutrients. Just make this a no brainer. Unless you have a lab and the skills to use it; choose ONE nutrient vendor whose products are built from the ground up for cannabis hydroponics and use their entire line. Do not mix and match. Vendors spend millions of dollars and years developing their products to work with each other. Take advantage of that. Follow their feeding schedule. Change the water/nutrient solution every week – without fail. Learn about Liebig’s law of the Minimum to understand why you are doing this. Look at the Liebig’s Barrel to visualize what we are talking about here. DO NOT MIX NUTRENTS INTO THE RESERVOIR; mix them in a separate container using water that has been aerated for a day or two following vendor instructions the day before the reservoir refresh. Doing this ahead of time will make it much easier to get the PH balanced and stable. A suction pump will be worth its weight in gold to help evacuate the reservoir for a refresh. Many product lines can and should be used at 50% of the vendor’s chart strengths in DWC but not all of them. Do a little research on your chosen brand.
4. PH. PH has absolutely everything to do with the uptake of nutrients into the plant. Let it range from 5.7 to 6.2 in DWC. This will allow the different components to move through the best uptake zones for that nutrient. Check the PH every day even multiple times per day is better. Roots not only take water and nutrients in they also exude substances that can dramatically change the PH in the reservoir in a very short period of time. I am talking hours here not days. Mix PH buffers into some water before adding to the reservoir to prevent burning the roots. Make small changes at a time. One full point is too much (5.2 to 6.2). It takes practice and vigilance to maintain PH in the proper range. PH problems have caused me more issues than all of the other environmental factors combined. The minute you take your eye off this it will bite your plants in the ass!
5. Botanicare HydroGuard. The only additive outside of your chosen nutrient regime I recommend. It is a must have. I would not even buy a bucket before I had this in stock. Root Rot is totally preventable with this. I live where it is not possible to maintain the reservoir temperature below 78°F in the summertime and it has gone as high as 82°F. The ability for water to keep oxygen saturation at that high of a temperature is minimized. Think stagnant pond! I have grown great plants totally root rot free using HydroGuard under these conditions. High temperatures are not the only thing that can cause root problems. Botanicare HydroGuard is a basic component to DWC. I am not affiliated with or compensated in any way for this endorsement by anyone except my happy plants with huge colas.
I have tried several ways to get a plant started. Top feeding seeds planted in small rock wool cubes or Park’s Bio Dome sponges supported in the net pot by PH balanced clay pebbles until the roots get down into the reservoir a couple of inches has worked best for me. Then stop top feeding to prevent crown rot.
So there you have it. Now 10,000 people will take issue with something I have laid out here and I may agree with many of them. I have moved on to growing hydroponically in rock wool cubes because it solves my oxygenation problems associated with high summer reservoir temperatures. I am telling you now that if I did not have heat issues in the summer I would still be growing DWC!
Technically what I use is called “Bubbleponics”. First your environmental needs must be met - light, temperature, humidity and air movement all need to be in range for plants to grow well. I will assume you understand these basic concepts. The rules for a good DWC are simple but not very forgiving. Plants respond adversely quickly to something out of range. The good thing is that they will also respond well to a correction quickly. DWC is an everyday task; in fact checking your plants many times a day can keep you ahead of needs.
Two tools that you cannot do without are a good PH meter and a EC meter; both should be equipped with a temperature gauge as well. Maintain them and replace them on the vendor’s schedule.
The five basic components:
1. Water. You could spend a lifetime trying to learn about water for plant growth but let’s keep it simple. Most people can use their tap water as long as the beginning PPM is 200 or less. If your water goes over this you will need to mix it with distilled or Reverse Osmosis water to get it below 200 PPM. Use a float valve and top off bucket to keep the water level in your reservoir consistent even small fluctuations can cause stress. Set the water level 1” – ½” below the bottom of your net pot. Aerate your water for a day or two before you intend to use it. This will help precipitate calcium carbonate out of the water and make it easier to control your PH. I just use my top off tank for this. The perfect reservoir water temperature is 68°F. This is the temperature that water holds the most dissolved oxygen. Do not use copper, brass or aluminum anywhere in your system; not even the tiniest fitting.
2. Air. Roots need air. An aquarium air pump and air stones provide this critical component. I always use two pump/stone combos for redundancy. Losing aeration even for a short period can be problematic. The smaller the bubbles are coming out of the stones the better. I use a UPS battery back-up on my air pumps. The volume of airflow needs to be high enough to saturate the water but not be so violent that the roots are damaged. Smaller bubbles allow more airflow with less violence.
3. Nutrients. Just make this a no brainer. Unless you have a lab and the skills to use it; choose ONE nutrient vendor whose products are built from the ground up for cannabis hydroponics and use their entire line. Do not mix and match. Vendors spend millions of dollars and years developing their products to work with each other. Take advantage of that. Follow their feeding schedule. Change the water/nutrient solution every week – without fail. Learn about Liebig’s law of the Minimum to understand why you are doing this. Look at the Liebig’s Barrel to visualize what we are talking about here. DO NOT MIX NUTRENTS INTO THE RESERVOIR; mix them in a separate container using water that has been aerated for a day or two following vendor instructions the day before the reservoir refresh. Doing this ahead of time will make it much easier to get the PH balanced and stable. A suction pump will be worth its weight in gold to help evacuate the reservoir for a refresh. Many product lines can and should be used at 50% of the vendor’s chart strengths in DWC but not all of them. Do a little research on your chosen brand.
4. PH. PH has absolutely everything to do with the uptake of nutrients into the plant. Let it range from 5.7 to 6.2 in DWC. This will allow the different components to move through the best uptake zones for that nutrient. Check the PH every day even multiple times per day is better. Roots not only take water and nutrients in they also exude substances that can dramatically change the PH in the reservoir in a very short period of time. I am talking hours here not days. Mix PH buffers into some water before adding to the reservoir to prevent burning the roots. Make small changes at a time. One full point is too much (5.2 to 6.2). It takes practice and vigilance to maintain PH in the proper range. PH problems have caused me more issues than all of the other environmental factors combined. The minute you take your eye off this it will bite your plants in the ass!
5. Botanicare HydroGuard. The only additive outside of your chosen nutrient regime I recommend. It is a must have. I would not even buy a bucket before I had this in stock. Root Rot is totally preventable with this. I live where it is not possible to maintain the reservoir temperature below 78°F in the summertime and it has gone as high as 82°F. The ability for water to keep oxygen saturation at that high of a temperature is minimized. Think stagnant pond! I have grown great plants totally root rot free using HydroGuard under these conditions. High temperatures are not the only thing that can cause root problems. Botanicare HydroGuard is a basic component to DWC. I am not affiliated with or compensated in any way for this endorsement by anyone except my happy plants with huge colas.
I have tried several ways to get a plant started. Top feeding seeds planted in small rock wool cubes or Park’s Bio Dome sponges supported in the net pot by PH balanced clay pebbles until the roots get down into the reservoir a couple of inches has worked best for me. Then stop top feeding to prevent crown rot.
So there you have it. Now 10,000 people will take issue with something I have laid out here and I may agree with many of them. I have moved on to growing hydroponically in rock wool cubes because it solves my oxygenation problems associated with high summer reservoir temperatures. I am telling you now that if I did not have heat issues in the summer I would still be growing DWC!
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At lower dosages using tap water the pH going into the reservoir will be between 6.1 and 6.3 No worries, the chelation factor still allows for proper uptake. HOWEVER...for this to work like that, I always adjust my top off water to a pH of 6.0 , and change my reservoir every 7 days or sooner. If a plant has used 14-16qts since the last water change and the week isn't up yet...change the water! Don't wait for the regular day. This is where note taking is important.
