Multi-Plant Recirculating DWC Test

[Xlr8]

Mr. Smith -

I let my water/nute levels fluctuate a fair amount in DWC. I usually started about 1 inch below bottom of net pots, and I would usually let it drop up to a couple of inches before I topped off. I have been noticing the Chocolope in my single bucket DWC seems to like life better with a couple of inches between her netpot and the water level, where the auto flower I grew in it before her seemed to thrive with a higher water level... I nearly killed the Chocolope with that higher res level in relation to the netpot. Hmm.

I agree with your DWC observations on all points. Though, it seems like water temps ARE to blame for a lot of things (sure is critical anyway!)

Ah, I'm really blazed right now on some Lucy I quick-dried. Took me forever to write that little post. bed. time. for. me. soon....

 

[Mr Smith]

Bassman, what is your water height levels? Its true that with running a chiller everything becomes easier but just by installing a chiller and a pump you just switched it to rdwc and the pump actually puts as much DO (disolved oxygen) or more than a airpump with airstones. To show a lil proof to what I am saying airstones in a large aquarium is not alway efficient enough to keep a large fish population alive but a waterpump style filtration system is specificly made for larger aquariums because moving and running water captures more than enough DO and has become the industries standard. We use airstones and bubbles with dwc because they are normally small systems and they make a spray of mist and water above the waterheight to wet and aireate root zones.When I bought my chiller I thought it would become the cure all of all problems. Instead it has been leading me to pinpoint other problems I thought were because of heat issues. Blaming problems on heat issues is easy since most grow rooms tend to run on the warm side but if the room is 75f or less then heat is not the primary factor when it come to problems. 68f is just the best number to trap DO in water.
I would clean the roots off your clones, ditch the clones that look really unhealthy and rinse and wipe out the machine. Keep your nute solutions simple. Hygrozyme is good shit, easy to use instructions and does not effect ppm so it can be used at full strengh plus it is compatiple with h2o2 or hydrogen peroxide since its just a enzyme with no living stuff in it. Also make sure your dwc machine is light proof if its a diy.

I removed fan leaves at the beginning of flower and stopped at after the 3rd week on this grow. The leaves grew back at different areas of the plant. I also pruned lower laterals because most of the plants are 5 foot tall. I think its pretty well documented earlier in the journal so it can be easily reviewed if you wish. This grow has been pretty easy and kind of boring since most problems were solved on the 1 plant grow experiment I did before this grow. I like easy and boring.

Xlr8, thank you very much for your input. Its very appreciated. I love your ebb system, its like the ebb n gro on steroids, much bigger system with upgrades.
I am a lucky dog, I still have 6 to 10 strains shelved in small amounts so I can play the pot snob routine and test drive the buds after its been fully harvested. Please tell me all about the Lucy after you harvest, Lucy is by what breeder? I will restocking on seed soon.

Pics are form 11/21 day 51 in flower. Pics were taken under normal light and wasn't altered ith comp.

I can't wait to take the light barriers down to be able to show the plants as a whole.

Buds are very pretty, cover with frosty trichs, smell is strong and acrid, almost sour, this is going to be some strong ass weed I'm thinking.

 

[GodSpeed]

Some serious frosting going on there mr smith looks like total KO.

 

[Mr Smith]

I am hoping for very potent but pretty christmas tree ornaments GodSpeed, thank you.

 

[Bassman59]

Thanks Mr. Smith.

I agree the pump is most certainly adding lots of air. That being said, the airstones give really tiny bubbles and these tiny bubble is what gets absorbed into the water. And hell it can't hurt one bit I'm sure. Also, the lower the temp the higher the DO rate is from what I've read.

The roots are looking ok on the clones. I get temp swings on the clone dwc because it isnt hooked up to the chiller. But I know that and am doing the best I can for now w/o a chiller for that tub. I got the tub sitting in another tub with water and I drop ice bags into it. I got my ice maker workin overtime baby!

I don't think I'll lose any of the clones from what it looks like now. And if I feel it looks bad I will pull them so as to not hurt any others. Not going to fret over it, since I knew going in I was way way ahead of schedule and couldnt get into my tent for numerous weeks.

Yes I love the Hygrozyme and use it.

 

[Propa Gator]

I agree the pump is most certainly adding lots of air.

And more importantly, more circulation to move stagnant water out of any root clusters

That being said, the airstones give really tiny bubbles and these tiny bubble is what gets absorbed into the water.

Nope, only the surface area of the tiny bubbles tranfer gasses, but even if so, what? Plants don't use O2 directly, nor any other gas in air except CO2. DO's value is that funky anaerobic nasty beasties can't stand any of it.

And hell it can't hurt one bit I'm sure. Also, the lower the temp the higher the DO rate is from what I've read.

Again, higher DO is less helpful than better circulation. Some Pie-eyed Piper has been singing "More DO is more better", but I ask you: for what? O2 does not enter the plant through the roots, nor through any other part of any green plant. Since so many people say or imply otherwise, let's ask Corey. He's our Aggie Alum with a Masters in Something or Other. Ask him what use green plants have for their poisonous waste gas, oxygen. I'll believe him, then I'll shutthefuckup.

Thankyou Mr Smith. for your indulgence My third espresso might have been...

 

[Mr Smith]

PropaGator, how come you have never been moderated to growmod or moderator? You are a extremely active member and you knowledge on growing is in the wow zone. If your ever interested, I can talk to Rob for ya if you haven't already been asked. He always has a need for good folk like you.
The BPN sponsor(Corey) is impressive with his knowledge, I wish that he was around back when I was a newb. I have to say that I really like his products so far, I like winning his stuff but I also have no problem buying it too. He's the best Sponsor I have ever seen in the forums.

 

[Bassman59]

hmm thanks gator, learn more every day.

My understanding of dwc is tons of air is good in the water. But I also see your point that the plant uses co2 rather than o2. And the points made on beasties.

edit: Interestingly I have known c02 is what the plants breathe and when reading tulips tutorial on dwc and lots of air/stones in the water, in the back of my mind I was saying "plants use c02". Didnt question it to get a reason why though. Often times that gut feeling is right, and need to question. At least to learn if for nothing else.

 

[Mr. Krip]

And more importantly, more circulation to move stagnant water out of any root clusters

Nope, only the surface area of the tiny bubbles tranfer gasses, but even if so, what? Plants don't use O2 directly, nor any other gas in air except CO2. DO's value is that funky anaerobic nasty beasties can't stand any of it.

Again, higher DO is less helpful than better circulation. Some Pie-eyed Piper has been singing "More DO is more better", but I ask you: for what? O2 does not enter the plant through the roots, nor through any other part of any green plant. Since so many people say or imply otherwise, let's ask Corey. He's our Aggie Alum with a Masters in Something or Other. Ask him what use green plants have for their poisonous waste gas, oxygen. I'll believe him, then I'll shutthefuckup.

Thankyou Mr Smith. for your indulgence My third espresso might have been...

Sorry this is a little long, but it's on-topic and worth the read:

Dissolved Oxygen Levels and Nutrient Temperature

Battle the Pythium Virus in Hydroponics

The essential for consistence in harvests with the utmost quality and yield.

The hydroponic nutrient solution is not just a mix of fertilizer salts and water, there are a number of organisms and compounds commonly found in our hydroponic systems that we need to be aware of. One of the most important of these is dissolved oxygen which is vital for the health and strength of the root system as well as being necessary for nutrient uptake.

Most growers are familiar with the need to have some form of aeration in their nutrient solution - whether they be in a recirculating or a media based system. In NFT systems, this is often accomplished with the use of an air pump or by allowing the nutrient to fall back into the reservoir thus introducing oxygen. However, the effect of temperature of the solution on the dissolved oxygen levels and on root respiration rates also needs to be taken into account. As the temperature of your nutrient solution increases, the ability of that solution to 'hold' dissolved oxygen decreases.

For example, the oxygen content of a fully aerated solution at 10C (50 F) is about 13ppm, but as the solution warms up to 20 C (68 F) the ability of the liquid to 'hold' oxygen drops to 9 - 10ppm, by the time the solution has reached 30 C (86 F), then it's only 7ppm.

While this may not seem like a huge drop in the amount of dissolved oxygen, we have to remember that as the temperature of the root system warms, the rate of respiration of the root tissue also increases and more oxygen is required by the plant. For example, the respiration rate of the roots will double for each 10C rise in temperature up to 30C (86 F). So the situation can develop where the solution temperature increases from 20 - 30C (68 - 86 F) during the day, with a mature crop, then the requirement for oxygen will double while the oxygen carrying capacity of the solution will drop by over 25%. This means that the dissolved oxygen in solution will be much more rapidly depleted and the plants can suffer from oxygen starvation for a period of time.

The symptoms of oxygen starvation which can occur in both NFT and media based systems can be difficult to pick up as they are very general signs. Media based plants are just as prone to oxygen starvation in hydroponic systems as those grown in solution culture, but here we must also take into account the 'air filled porosity' of the media used. This is simply how much air can permeate between the particles in the substrate and selection of a free draining media which won't break down will ensure that maximum aeration is going to reach the root zone. Injury from low (or no) oxygen in the root zone can take several forms and these will differ in severity between species. Often the first sign of inadequate oxygen supply to the roots is wilting of the plant during the warmest part of the day when temperature and light levels are highest. Insufficient oxygen reduces the permeability of roots to water and there will be the accumulation of toxins, thus both water and minerals cannot be absorbed in sufficient quantities to support plant growth particularly under stress conditions. This wilting is accompanied by slower rates of photosynthesis and carbohydrate transfer, so that over time, plant growth is reduced and yields will be affected. If oxygen starvation continues, mineral deficiencies will begin to show, roots will die back and plants will become stunted.

Under continuing anaerobic conditions, plants produce a stress hormone - ethylene which accumulates in the roots and causes collapse of the root cells. Once root deterioration caused by anaerobic conditions has begun, opportunist pathogens such as Pythium can easily take hold and rapidly destroy the plant.

Another more visible and longer term effect of oxygen starvation which also occurs in waterlogged crops is leaf 'epinasty'. Epinasty is a downward curvature of the plant leaves, resulting in plants which look wilted. If the oxygen starvation continues and is severe, then eventually leaf chlorosis yellowing, premature leaf and flower abscission will occur.

There are a number of things we can do to make sure our nutrient solution is carrying sufficient dissolved oxygen, and this is important when we consider that many of the root diseases encountered in hydroponics have occurred because the root system was damaged in some way, with anaerobic conditions being a major factor in many situations. The first most important factor to remember with oxygen is that the best way to introduce this gas into the nutrient is to have the solution fall back into the reservoir, and the greater the drop height, the better the aeration effect. Breaking the flow up into a fine shower also assists by introducing more air bubbles into the tank. Secondly, while nutrient ppm (EC) does reduce the oxygen carrying capacity of the solution, the effect is very small and temperature has a much greater influence on oxygenation.

Reducing excessive solution temperatures will ensure more oxygen can be held by the solution and the rate of respiration by the roots will be kept down to optimal levels. Thirdly factors such as nutrient flow rate, channel width, length and slope have a large effect on oxygen levels- faster flow rates, greater slopes and shorter channel lengths all assist with prevention of oxygen starvation.

Perhaps one of the commonest problems in hydroponic systems is the Pythium pathogen and what many growers don't realize is that Pythium being an 'opportunist' fungi, often takes advantage of plants which have been stressed by a combination of high temperatures and oxygen starvation in the root zone.

Pythium is usually described as a 'secondary infection' meaning that the Pythium spores which are actually common in just about all hydroponic systems, don't actually attack the plant until it has been damaged in some way. Even very clean hydroponic systems and grow rooms which are isolated from the outdoor environment will have some Pythium present as these fungal spores are naturally present everywhere on a world wide scale - in the water, soil, vegetation, carried in the air and in dust, so its difficult to eliminate the source of this disease. However, one way we can reduce the 'spore load' is to sterilize any water supply which may be contaminated with high levels of pythium - water from dams, and streams should always be sterilized before use for this reason if Pythium is a problem.

Under the right environmental conditions, virtually every plant species is vulnerable to Pythium, which not only causes 'damping off' of seedlings but causes root and stem rot of older plants. Symptoms of Pythium on older plants are a wet rot, root systems will be browned, roots hollow and collapsed.

Plants may appear to grow poorly, and wilt for no apparent reason - indicating that an examination of the root system is called for. Pythium has an optimum temperature range for infection of plants, this is generally between 20 - 30C (68 - 86 F), although infection can occur outside this range when damaged plant tissue is available for rapid colonization by the pathogen. Low concentrations of Pythium that may not cause problems at lower temperatures will be disastrous at higher temperatures, particularly where the warmer conditions are associated with a lack of oxygen in the root zone and plant stress.

The best preventative measure against Pythium attack is a healthy, rapidly growing plant as this is an opportunist pathogen and will enter at the site of tissue injury or if the plants are overly succulent, weakened or stressed for some reason. Often root damage during the seedling stage as plants are introduced to the hydroponic system is a danger time for Pythium infection. Pythium is of greatest threat during the seed germination and seedling development stage when plants are most vulnerable to attack, and adequate control and elimination of the pathogen during this stage is the best preventative measure of Pythium control in hydroponic systems. Strong healthy plants will develop resistance to Pythium attack during the seedling stage and this will prevent problems at a later stage of growth.

Other preventative measures include the use of a well drained media, thorough disinfecting of all equipment between crops, and control of pathogens during the seedling stages with a suitable fungicide, long before they are introducing into your hydroponic system. Occasionally a very high spore load, combined with excessive temperature will result in Pythium attacking even healthy plants, if this is the case, it is likely that there is an active source of spore production present, and the system must be shut down and disinfected. Sterilization of the water supply with UV light, hydrogen peroxide or ozone , before nutrient are added however, is effective at reducing or eliminating Pythium from the original water supply.

Therefore by ensuring your plants are healthy and stress free, you will not only get the highest growth rates possible, but also prevent problems such as Pythium infection occurring. The variables to remember with regard to the nutrient solution is that aeration is vital to maintain the dissolved oxygen levels, temperatures should be keep within an optimum range, and Pythium is always present, but a healthy plant is the best measure of protection against a disease outbreak. About the oxygen requirement of plants when in flower...its not always the case that plants require more oxygen because they are in flower, a plants oxygen requirement is linked to the size of the root system, temperature and nutrient uptake rates, rather than the presence of flowering. So since plants such as tomatoes tend to have a rapidly developing root system at the time of flowering, its important to maintain adequate oxygen levels. With tomatoes the requirement of oxygen in the root zone increases gradually up until the time of maximum fruit load and rapid fruit expansion, where the high rates of nutrient uptake increase the oxygen requirement quite dramatically. On the other hand, if oxygen is deficient during flowering, then the flowers and subsequent fruit may drop off as a result, or they may be undersized.

 

[Bassman59]

Thanks MR K!

 

[Propa Gator]

Battle the Pythium Virus in Hydroponics

Who wrote that piece? He wrote all around O2, not zeroing in on specific need nor why exactly. He tries to imply that less is insufficient.
The difference is like the litmus test: pass or fail, aerobic or anaerobic. That's it. In all the micro-zones of the root system. Either great air permiability like in the coco coir that I prefer to use, or an efficient circulation system of water, containing certain salts.
Spore load? malarky! It's all about the conditions. Air, mostly. Germs & spores are everywhere unless radical HEPA filtration & containment/quarantine are employed. Who's the bubble-boy now?

You watermen have a alot of dickin around to do, or the slime is gonna get you

 

[Mr. Krip]

Who wrote that piece? He wrote all around O2, not zeroing in on specific need nor why exactly. He tries to imply that less is insufficient.
The difference is like the litmus test: pass or fail, aerobic or anaerobic. That's it. In all the micro-zones of the root system. Either great air permiability like in the coco coir that I prefer to use, or an efficient circulation system of water, containing certain salts.
Spore load? malarky! It's all about the conditions. Air, mostly. Germs & spores are everywhere unless radical HEPA filtration & containment/quarantine are employed. Who's the bubble-boy now?

You watermen have a alot of dickin around to do, or the slime is gonna get you

Good question & more good points, Propa! The article doesn't list an author, but found it on a gardening site. Here's a few more that are a little more scientific for you with authors & references listed

Fertilizers and hydroponic systems by Terra Aquatica

Temperature and Dissolved Oxygen in Hydroponics | Bilberrybrian.com

At Guelph

Now, with all of that info, I'm still not sure I can answer the question "Why", but the results seem to indicate better growth with elevated (to an extent) DO levels.

BTW...I did an "informal" experiment with my two waterfarms. For the first few weeks, I had an airstone in one and not the other, and the difference in growth was notable, even after I added the airstone to the 2nd res.

 

[Propa Gator]

PropaGator, how come you have never been moderated to growmod or moderator? You are a extremely active member and you knowledge on growing is in the wow zone.

I've been moderate, and I've been moderated. For a while, I was a moderator on this site, but...
Personal character defects & shortcommings interfered, ie: I'm self-indulgent and lazy. I have at least one screw missing, and others are loose. Also, I'm an arrogant motormouth who often rants on about some kinda crappola or other. Not a natural team player, nope; not Propa Gator. Ask my cat, he'll tell you.

The BPN sponsor(Corey) is impressive with his knowledge, I wish that he was around back when I was a newb.

We had Ed, and Cervantes. And Peter's water-soluble fertilizer.

I have to say that I really like his products so far, I like winning his stuff but I also have no problem buying it too. He's the best Sponsor I have ever seen in the forums.

I'm thrilled with two-part quality & terms. Whenever he speaks of horticultre, I'm there wearing glasses

 

[Mr Smith]

This is why I am a simple dick that goes through trial and error. I'm a grower, I like to know the knows and nots but my lil brain can only understand and absorb so much info. I might not be a very good grower but I do better than some and can hang with the others. I try one way, record than try another. I like knowing why why why but I like increased numbers better or a don't do if numbers decrease. Overall I am happy how the new diy performs. I think another grow with a fine tune in levels and nutes will be enough to say I got this system down and with a 3rd grow experience I should be able to list most of the dos and don'ts. By following this journal and the 1 plant test journal I believe most people can use the info to create and run a similar diy with a pretty good success margin. The explosion of growth with rdwc is hard to beat.
Thank you for helping a simple grower get the right technical jargon in the journal. This journal is almost at a end and I will be flowering a darkstar mum next with rdwc. The goal for the mum is a 40 oz indoor bush like Heath like's to do. Should be interesting and I hope some of you guys will check to see if I can accomplish such a tremendous goal.

Prop, thanks for being one of my closest friends on this site.
Krip, Xrl8 and Bass, thank you for all your help, it is much appreciated.

If anybody wishes to comment or tell what they might have done differently this is the time to do it, as I said this journal is almost done and will be retired into the archives. Thank you for your time.

 

[GodSpeed]

I might not be a very good grower but I do better than some and can hang with the others.

This is probably the funniest thing iv read all day!

I only hope i can produce anything close to your standard of growing Mr smith.

 

[Mr Smith]

I was told that I am kinda hard on myself but I try to keep a high standard. I am still looking for the perfect grow and I honestly thought I would have achieved it by now. This is why I am not a very good grower, I have only ever had 1 grow that was able to beat the one gram per watt ratio. Plus I am stupid and have to relearn the basic every now and again. Sucks when a grow op is finished and you know you could have done alot better. I am pretty positive that I am over a pnd but there is noway that this is a 1200 gram grow.

 

[GodSpeed]

Yes i would say your incredibly hard on yourself!

I dont even look at the ogpw ratio as i might as well give up now if i did. If i was growing under 1000w I would rarther have 500g of dam right dank then 1000g of standard. You have been a massive inspiration to myself and 1000's of others, its incredible to of even seen somthing so special in my life time.

 

[SteveHman]

I think there must be better metrics to gauge success than GPW. For example, we go 12/12 from clone--no veg time and finish in ~8 weeks. If we went full veg we would need an additional ~4 weeks. Let's say the 1st grow produces 420 grams with 600w and the second produces 600 grams with the same 600 watt lights. Which is a better harvest?

I am putting together a spreadsheet that is going to track total KWHs used (and electrical costs), cost of nutrients and number of days to finish. I think that it will be surprising and we may learn that it is better to get .73 gpw in 8 weeks of 12/12 then to get 1 gpw with an additional 4 weeks of 18/6.

By any measure I would say your grows are top-notch and if you tracked the overall cost-per-gram you would be at the upper end of the scale for performance.

 

[Propa Gator]

I was told that I am kinda hard on myself but I try to keep a high standard. I am still looking for the perfect grow and I honestly thought I would have achieved it by now. This is why I am not a very good grower, I have only ever had 1 grow that was able to beat the one gram per watt ratio. Plus I am stupid and have to relearn the basic every now and again. Sucks when a grow op is finished and you know you could have done alot better. I am pretty positive that I am over a pnd but there is noway that this is a 1200 gram grow.

Mr Smith, you are a better grower than you'll admit. You engineer conditions rather than buy products. Your NFT table being your exception to your normal DIY, and all with HIDs. I'm inspired by your grows because they are within reach to copy, rather than requiring a bank loan to buy a set-up.
Two main factors leading to your high g/w grow, were vertical bare bulb and dense, small, numerous plants. We both know that g/w returns are only one of many benchmarks of efficiency. The space required is also critical and expensive. So is time spent on set-up, maintainance, and processing. Risk realities also vary with the set-up. That you manage to harvest high quality weed often, is huge. If you lacked any book-learning at the onset, you've moved beyond that now, from doing. And open-minded observation.
Yield quality & quantity are largely the result of genetics, if good conditions are engineered & maintained.

 

[Bassman59]

Stevehman,

I know you basically go straight into 12/12. But have you considered timing a veg to start at 4 weeks of flower and rotating into 12/12 upon harvest? I'm sure you would agree the 4 weeks veg would yield more. This isnt always possible for some people based on the type setup and area available to them. But it would be interesting to see the return on G/kwh, as well as G/$cost of grow between the two styles.

I'm obviously not set up for lots of plants to go immediate 12/12. To do so would be quite costly for me at this point.

That being said I am enjoying my clone-veg manipulation in grow #2. Hoping of course I yield a substantial amount more than grow #1.