Lazy Man's Way to Cleaner Hydroponic Cannabis

Discussion in 'Hydroponics / Aeroponics' started by Douglas.Curtis, Aug 9, 2016.


    Douglas.Curtis Well-Known Member

    OR How to Manage Roots In/Out Hydro Reservoirs With Ease

    Basics of Hydro
    Everyone complains, hydroponics takes a lot of time, is complicated to understand and difficult to maintain. I say hydroponics is simple and takes little time. The difference is in the reservoir management. Regardless of the system used, a few key points make management of hydroponics a piece of cake. (Mmmm... caaaake!)

    When each of these key points are understood and applied, the time you spend working with your hydro system drops dramatically. This leaves you more time for working with the plants or other tasks in life. I learned these methods over 15 years ago and they've served me extremely well.

    The following information works best in a high VPD environment. I use low temperatures and low humidity (72F canopy temp, 20-25% RH), others use high heat, high humidity. Both methods produce a high VPD environment, causing high transpiration rates.

    I believe low humidity produces higher quality, high heat and humidity is much easier to maintain. Low humidity also has significantly lower pest breeding and mold germination rates.

    Building Blocks for Any Hydro System
    The following are a few key points for all hydroponic systems.

    Clean Water
    You want easy hydro? You'll definitely want to always use clean water. I prefer reverse osmosis filtered water. R/O is pH neutral and free of contaminants. Everything cannabis needs will be supplied by your nutrient mix. No guessing.

    A Balanced Nutrient Profile
    Providing an accurate mix of elements, required by a plant, allows maximum healthy growth rates. A properly balanced mix will have sufficient levels of each macro and micro element, without having excess within a healthy pH range. Cannabis can and does bind some elements directly to cell walls in new growth. A balanced nutrient profile produces the cleanest end cannabis through prevention of this action.

    Professional/Pharmaceutical Grade Nutrients
    The cleaner the nutrients, the fewer problems and potential contaminates you have to deal with. I recommend using only pharmaceutical grade nutrients for cannabis. 99.9% free of contaminants.

    pH Swing Compatible Additives

    Using the natural upswing in pH, as the plants absorb nutrients, is the cleanest way to achieve a full and cyclic pH swing. Additives that alter pH, either directly or though biological activity, must be carefully used.

    Roots-In and Roots-Out
    Though the basics are the same, there are two general types of hydroponic systems. Roots-in, where the roots are constantly exposed to the nutrient solution, and roots-out, where the roots experience repeated drying out periods. The pH management and correct root zone temperatures are different for each type. Roots-In systems also require oxygenation of the nutrient solution.

    Roots-in systems MUST keep the root zone (nutrient solution) between 65F and 68F. Higher or lower temperatures increase work and decrease results. 68F is preferred for maximum growth rates.

    A full and cyclic pH swing from 5.4-5.8 MUST be allowed to happen in the reservoir. Allowed, through proper res management, not forced.

    Roots-in systems constantly bathe the roots in solution. Since these roots require oxygen, the solution must be sufficiently oxygenated. This is accomplised with airpumps, airlines and airstones. A good rule of thumb is to provide at least 3 watts of airpump power for each 10 gallons of nutrient solution.

    Roots-out systems MUST keep the root zone at 75F-78F, for healthy growth. Temperatures below 75F stall growth and temps above 78F invite root rot.

    The healthy pH swing in a roots-out system is a narrower range than roots-in systems. This is due to the pH dropping in the root zone, as it dries out between waterings. The healthy pH range for a roots out system is generally 5.5-5.8.

    Reservoir Size and pH Swing
    Cannabis responds to a healthy pH swing in the root zone. Cannais responds extremely well to a swing with a 7-10 day cycle. Since the swing is largely based on how fast plants absorb nutrients, a reservoir size needs to be matched to the light and number of plants being used.

    The more gallons of nutrients in the reservoir, the longer it will take for the pH to swing. The fewer gallons, the quicker the swing. The standard size for a 1000w HID and a full canopy is 40-45 gallons.

    Mixing Your Nutrient Solution
    Mixing the nutrient solution is a simple process. Filling the reservoir with water. Adding nutrients, mixing well, adding additives, if any, and adjusting the initial pH.

    Add r/o water
    Fill the reservoir to the level you're going to use.

    Add Nutrients and Additives (if any)
    Add your base nutrients in the order your manufacturer recommends. I use a general mix which works well as a general nutrient for 'cannabis,' consisting of 8ml/cc of GH Flora Micro and 16ml/cc of GH Flora Bloom, per gallon of water. (Yes, commonly referred to as the Lucas Formula)

    This means I calculate the number of cc/ml's of micro I need and mix it in thoroughly. I then mix in the calculated amount of bloom. Additives are added next. The main additive I always use with Lucas is .5/1g of epsom salts (magnesium sulfate) per gallon.

    pH to Lowest Starting pH Level
    The starting pH is going to be different for roots-in and roots-out system. I use GH powdered pH up as it works well and is a potassium based product. Roots-in systems are simple at 5.4. Roots-out systems are generally 5.5, depending on the pH drop between waterings.

    Daily Reservoir Management
    All hydroponic systems require daily tending. It takes only a few minutes to do the following.

    • Measure Transpiration Rate
    • Top off the Reservoir
    • Check the PPM/pH
    • Add Nutrient (If necessary)

    Measure Transpiration Rate
    Once a day, look at the level of the nutrient solution, to see how much has been transpired/evaporated. Watching changes in this rate is an important piece of information regarding your plants. The lower the level in the reservoir, the more water is being transpired and evaporated.

    Top Off the Reservoir
    Easiest part of the day, add r/o water until the reservoir is re-filled. With automated float valve systems, I lose the transpiration info and the slight pH dip, without adding a way to calculate added gallons and possibly a timer on the fill valve.

    Measure pH and PPM/EC/TDS
    Once the reservoir is topped off to initial volume, check the pH and ppm/ec/tds. Write these numbers down to chart the progress of the reservoir.

    Add Nutrients
    When the pH hits 5.8, add nutrients. The nutrients act as a pH down. You'll add enough nutrients to return to your 5.4 or 5.5 starting point.

    When Transpiration Slows
    This is the point in flower when the plant begins moving from growing larger flowers to producing more oil. You'll notice the plants are not using as much solution, the level in the reservoir isn't as low each day.

    Cut back on the amount of nutrients you add or pump out some solution and replace it with r/o water.

    The goal is to match the previous transpiration rate.

    Those are the Basics
    This is the essence of lazy man's hydroponics. Setup is straightforward, daily management is quick and simple, results are smashing.

    When Do You Dump the Reservoir?
    5 days before harvest, pump that (should be) fairly weak solution out into the garden or on the lawn or flower beds outdoor. Replace the solution with r/o water.

    When you start with r/o water and use only clean nutrients and compatible additives, your pH swing is natural and complete and your reservoir stays clean. There is no need to dump a perfectly healthy reservoir, other than before harvest.

    When all environmental and mentiond hydro conditions are met, and there are no other pest, algae, chemical offgassing or other issues, this method works 100% of the time.

    Questions? Ask Below
    and I'll be happy to share/help on subjects I have experience with. :)
    ChaosHunter, Yesdog, jronnn and 4 others like this.

    Douglas.Curtis Well-Known Member

    Who's ready to quit changing their res every week? LOL[​IMG]
    ChaosHunter and swedsteven like this.

    swedsteven Well-Known Member

    I like your point but I'm still not sure on leaving the same water .I leave it for 3 week for veg but in flowering I like to change the water every 2 week but after 2 week only 100 liter left on 300 liter total and my pH is really stable ppm to. I don't top of I leave them drink for 2 week then empty all the water then refill with fresh water .nutrients and beneficial bacteria hydroguard.
    do you use bennies

    Douglas.Curtis Well-Known Member

    When you use only clean nutrients and feed only what cannabis requires, there's zero need to dump.

    I use GH Flora, liquid silicon, pH up and a dash of floralicious+. That's it, no need to use additives to 'keep' a res clean when managed properly. I don't use chlorine or h202 either.
    HydroRed, VegasWinner and swedsteven like this.

    Douglas.Curtis Well-Known Member

    I completely missed this in your reply.
    Apparently you missed the "Top Off Daily" portion of my post.
    As for stable pH, cannabis grows so much more cleanly with a cyclic and full pH swing. (the quality difference is amazing)

    guardiangk Well-Known Member

    Agree with some of that.

    Douglas.Curtis Well-Known Member

    Please, do tell?
    Since this is based on 15 years of hydro, the same way, I'd like to hear where you don't agree. Perhaps I can explain where you're going wrong?

    guardiangk Well-Known Member

    Sure. This isn't about right and wrong, it is about what works for you and what works for others. I am not here to measure dicks. I know what I have tried and what has worked in my garden and what hasn't. If you would like me to share the experience I have in my garden, I would be happy to.

    I do not agree with RO water. When you read an analysis of your tap water, you can actually use some of it to your advantage. I use tap water from seeds and clones all the way thru finishing. I can tell you for sure that tap water works better in my garden. It is a great way to up the PH, since my drops naturally over a week. Oh and it's a lot cheaper.

    I run my canopy a lot hotter. High 80's low 90's. With 30%-40% RH. In my garden it helps increase transpiration but still keeps it under photosynthesis rate.

    As far as PH balancing goes, I use silica and tap water to raise the PH whenever possible. My PH drops. I use my swing a lot more than you do. I will let mine go from 6.1/6.0 down to 5.0 or so. Then raise with either silica or tap water as I mentioned.

    My system is "roots in" as you said. Yes the temps you show are best for dissolved oxygen, however my res has gotten in the low 80's before and still with white roots.
    Again, I would agree with you on what is ideal, but there is a larger temp swing that is still in an acceptable window.

    I will say it appears our hydro systems are a little different. Which is fine :)
    HydroRed and OneHitDone like this.

    Douglas.Curtis Well-Known Member

    Indeed, this is why I explained it the way I did, this will work with all growing situations. When followed properly.

    Cannabis is extremely picky and I (and many other growers) do not have time to minutely analyze the changes in the local tap water. Using r/o is extremely clean, in nearly every spot on the earth. Once you learn clean hydro with R/O, you will not have to re-learn when your water supply changes. Almost all tap water has contaminants in it which cannabis does not need and yet it will absorb it anyway.

    This is easier and more common. My research shows higher trichome density at lower humidity and temps. As long as transpiration is high, you can still grow clean cannabis with this hydro method.

    Using tap and silica during flower creates harsher burning cannabis, with a heavier ash. When you use r/o, the swing is steady and cyclic, extremely necessary for properly feeding cannabis 'cleanly.'
    In 15 years, with this method, I've never seen a plant that *liked* above 5.8 or below 5.3. I've also used the same balanced nutrient mix for those 15 years.

    69F is the maximum you can use in all areas and NOT have to use additives or bennies for res control. I go 3 months without a change, can you do that at 80F?

    Same system, different management methods.

    I'd say your biggest drawback would be your use of the tap and silica. Switch to pure r/o (get a filter for your house) and do a few runs. Be sure to save some of your tap/silica buds in a jar, the comparison will be eye opening. :D

    j to the c likes this.

    guardiangk Well-Known Member

    I appreciate your concern over my drawbacks. One of them you mentioned was using silica.

    You do know that is the 2nd most abundant mineral in the soil, right?

    You know it is recommended for plant growth?

    Here are some links for you.$FILE/BC 2013-4 p14.pdf

    You do know cannabis is a plant right? Extremely picky? A lot of plants are WAY more picky.

    You have time to grow, but no time to read your water report? Lazy, lazy, lazy. It really just takes a few minutes lol.

    You mentioned your research, what was it? Test plants? Control Plants?

    You know what, nevermind.

    I will leave you with one thought, I usually tend to steer clear of people who constantly give you their resume, and telling you what you are doing wrong. Just some friendly advice.

    Douglas.Curtis Well-Known Member

    Yes, and cannabis needs extremely little to grow awesome flowers. Your flowers NEED a grinder to break up, while I simply have to gently crush a bud against a bowl with my thumb.

    Look up dynamic and hyper accumulators. Extremely picky as in their environment for growing cleanly. Picky is the wrong word there.

    Excuse me? I have zero interest in 'reading my water report' so I can go mess around with custom nutrient mixes. I use a known formulation that works awesomely well. Why would I consider screwing with that and making life difficult? Btw, water reports change all the time, r/o water doesn't.

    8 years of constantly changing the way I grow. Some side by side for verification of more difficult to determine issues.

    Yeah, I'm answering your questions for newbies and other growers who are willing to listen. I've given perfectly valid explanations of why this is cleaner. You simply keep trying to validate your dirty methods. Not my issue really, though I really appreciate your questions, I know others will get a great deal out of my having answered them.

    Good Day :D
    Bareback likes this.
    Budley Doright

    Budley Doright Well-Known Member

    Im so dirty :(.

    jronnn Well-Known Member

    what do you mean in that first part with the cyclic ph swing?.... flood and drain in pots with hydroton counts as "roots out" right? you think the best temp for the roots in a pot is 75-78? and if the ph drops between waterings wouldnt it be better to keep the ph a little higher like 6.0-6.2?
    Douglas.Curtis likes this.

    Douglas.Curtis Well-Known Member

    Cyclic, as in happening regularly. Roots-In is 5.4 to 5.8 in 7 to 10 days, then nutes are added and it's back to 5.4. Roots out has a bit more of a pH swing between feedings, so you start at 5.5 to 5.6, depending on your particular setup/medium, and let it rise to 5.8.

    F&D is roots out, correct. The pH drop in the root zone between feedings is not a full pH swing, it is a small one. Approximately .15? Haven't personally measured it, yet nutrient below 5.5 has usually had issues for me. As for going to 6.0-6.2, I've not personally seen any benefits with the lucas mix I mention. You'd still be flooding with 6.0, too high, since the pH drop doesn't begin instantly.

    I've run f&d at 75F-78F in the root zone(hydroton in netpots), it seemed to work well for me. I know I had nothing but nutrient problems and slower growth at 72F and below. I'm not sure what the optimums are, someone with more roots-out experience would be able to tell you that.
    jronnn likes this.

    weedemart Well-Known Member

    rootzone temp depend on few factor but most of the time optimal is 68-70F with the extreme 65F-72F

    75-78F in hydro is not recommended for 2 reason: past 70F, DO is Under 8 mg/L and the bacteria activity increase , these conditions can lead to slime and root disease.

    btw roots-in , roots-out , i dont like the terms. its more about the type of medium, inert or organic and type of system, recirculate or dtw...

    I would be more confident with high temp using an organic medium in a dtw system than flooding a table with inert medium such rockwool or hydroton because a sterile environnment is easier to get infected by root disease since theres no micro organism competition.

    dumping res every week is not only to keep your rez/system clean, it make sure the element stay in balance. dont forget micro organism feed on organic , even if you use 100% synthetic nutes, your plant still exude organic substance and overtime they accumulate and bad bacteria population can explode if you dont change your rez.

    changing rez every week is a must in recirculate system

    ideal ph is closer to 5.8-6.2 than 5.5-5.8 , the idea to start low is from recirculating system where ph rise overtime or from using alkaline medium such rockwool
    Last edited: Aug 18, 2016
    jronnn likes this.

    weedemart Well-Known Member

    clean cannabis imo, refer to a product with very low content of heavy metals and end residue

    jronnn Well-Known Member

    ahhh okay i get what youre saying now makes sense but its funny you say that, in the winter when my res temps were like 60-65 it took like a month and a half for my plant to reach a foot but i also hear the higher temp can result in low dissolved oxygen and obviously pythium but right now my temps are like 74-80 (depending on temps outside) and theyre growing more than ever

    you both seem knowledgeable so this question is for both of you...I have what im 99% sure is cyanobacteria that comes back after a week or 2 of res/tray cleaning/sterilizing... no matter what temp or how perfect everthing else is, it always comes back... i was using 29% h2o2 @5ml/gal every 3 days but even then itd still be back after 2 weeks. right now i been trying pondzyme with hydroguard for a week and im starting to see a thin film of it.. my question is do you guys reccomend anything for this? have either have you had this problem? its a clearish snotty/gelatin like substance that floats around or sticks to the walls. ive looked into the heisenberg tea and i might order the materials tonight but is there anything else you guys would reccomend? i have a 2x4 flood tray with a 23 gal res, plants in hydroton and since i stopped the h2o2 and started using the hydroon my ph rises from like 5.9-6.3 in 1 day
    Last edited: Aug 18, 2016

    Douglas.Curtis Well-Known Member

    Your temp recommendations are for roots constantly exposed to nutrient solution. When roots are drying out between cycles, there's more oxygen available, I assure you.

    All systems with roots constantly In solution are handled the same way in the reservoir, with very little differences between systems. Roots out systems also handle the same way in the res, with very little differences between mediums. I'm open to any suggestions reflecting this.

    The evaporation of the water in the nutrient solution sets of a very nice, humid, environment for the root zone. I have no experience with using organic hydro, no comment.

    My experience says dumping the res within a 3 month period is a waste. The key is starting with a balanced nutrient profile. The closer that profile is to your particular strain/phenotype, the longer you'll be able to run a res without issues. I generally start to see pH spotting at around 4 months, this is why I don't usually have to change a res during a flower run. Should I ever run a 6 month strain, I'll most likely do a res changeout every 2 months, just to keep things optimum.
    I've never had an 'explosion' of bacteria or anything but a crystal clean reservoir at harvest dump time. I'm also extremely picky about what I put in my reservoir.

    Another reason why I don't recommend them. Too many nooks and crannies for 'issues' to breed. DWC is a simple tub, with some roots hanging in it. :)
    *sigh* Please re-read what I wrote regarding the pH swing and cycles.

    rkymtnman Well-Known Member

    chlorine AKA HTH pool shock or dutchmaster Zone. sterile res all the way
    rollyouron likes this.

    Douglas.Curtis Well-Known Member

    My definition is cannabis which is as close to "only cannabis" as possible, meaning without any residues at all. Yes.

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