Ask Lucas

Sounds like you might be on to something. I was going to ask if they were clones or from seed. Seed plants sometimes act differently, because they aren't indenical like clones are. (Although I also get clones which don't all grow exactly the same either ?! But they mostly do. )

Seems like one being the mom, with questionable roots, and the other being a fresh clone would be a reason for the issues you've had.

[FredFarts]

Lucus, I know you are anti additive and maybe I just answered my own question But....
Would adding B'Cuss root stiulator to the veg tank help with roots? I know the bigger the roots the better the plant. WDU think??

ok i just check my roots and plant number one has a nice pile of slimy root along with some good roots plant 2 roots still look nice and white. i found out why ph is out of wack . now my qustion can i add some hydrogen peroxide or some protekit to help the roots or is it a loss cause just added some rain water as my add back and check my ph and it was 3.1 again.

[ntstephenson]

Slimy roots indicate low DO levels (and also causes pH drop). Either reservoir temps are too high (above 72 degrees) or you aren't using a big enough airpump/airstones. Until this situation is fixed, no remedy will be long lasting.

Fix the DO problem, then either remove the sickly plant, or if it is still salvageable, remove as much slime as possible and run a weak solution of H2O2 in with your nutrients. Refer to others as to the proper concentration of H2O2, as I haven't needed to use it in a while.

Another likely cause of slimy roots is additives. Don't use them. Use a balanced nutrient formula, H2O, and lots of DO, and sit back and watch your trouble free grow.

[lazi]

When using the lucas formula I don't need to buy calibration liquid for my EC meter. This correct? Make up a US gallon (ie. 4 litres) of 0/8/16 with RO water and that's what I calibrate the meter to. Seem to remember the figure 1.7 for EC meters.

Re. addback. A 50 gall res starts with 0/400/800. If the EC drops to 90% of original then the res now contains 0/360/720 and the addback is 0/40/80. (Float valve for auto top up.)

Just checking on the above in case I've remembered it wrong.

Being more specific I'm struggling with the budget and something has to give. Going to be running the first grow without a Ph pen. (The one I've got is too old to trust.) What EC range should I aim for to avoid Ph problems. Last full grow without res changes never had the Ph out of range so I'm hoping it'll be the same albeit with a smaller res. (50 gall.)

My RO unit hasn't been run for 2 years but has only done 1 grow. Haven't dismantled it or anything, just turned off the water supply and left it alone. Opinions to it's safety? I'll be running it for some hours before using the water on plants. Tap water here is heavy on chlorine, hoping that's enough to keep it good. Means a smaller waterpump if I have to repalce membrane and/or filters.

[mace]

Hi lazi

Quote:

When using the lucas formula I don't need to buy calibration liquid for my EC meter. This correct?

This is NOT correct.
The Lucas formula/0-8-16 has many advantages, but calabrating your meters with it is none of them!!!
0-8-16 per US Gallon (1.785Liter) RO water has an EC of 1.9mS/cm, not 1.7

Calibrate your meters guys, or they will lie to you!!!
Simple as that.

peace,

mace

[lazi]

Just trying to understand why...Fresh gallon of 0/8/16 in RO, EC meter reads 1.9 cuz I've just set it to that but it might be wrong... do EC/TDS meters have 2 sets of calibration liquids like Ph pens? In order to get the linear scale right I assume.

3.785 is a bit out from the 4 litres I was going to use, I'll measure the total water in litres and convert to US gallons, safer that way.

[ntstephenson]

Quote:

Originally Posted by lazi

Just trying to understand why...Fresh gallon of 0/8/16 in RO, EC meter reads 1.9 cuz I've just set it to that but it might be wrong... do EC/TDS meters have 2 sets of calibration liquids like Ph pens? In order to get the linear scale right I assume.

Not sure of the specifics, but...

pH is a logarithmic scale. 8 is ten times more than 7.

EC is a measurement of electrical conductivity. It is linear, in the same way a mercury thermometer is linear. If you calibrate it to a known (like ice water with a thermometer) all other readings should be correct (?). I have never calibrated my TDS pen, maybe I'm missing something as well...

Some people do successfully use Lucas formula without TDS pens, but they usually change out nutes every two weeks or every 100% addback of RO water, so this method is somewhat wasteful on nutes. Another method is to estimate 1/3 strength at addback, but this is situation dependent as light levels and relative humidity affect transpiration rates and therefor changes the ratio of water to nutes used, so no general rule will fit all grow rooms.

Bottom line, I would suggest contacting the manufacturer of your pen (or check online) to see if two points are needed to calibrate. If not, I don't see any fundamental problem with using 0-8-16 in RO water as a calibration, any more than any other calibration solution at a given EC. If there's something wrong with your pen, however, I would suggest replacing it if at all possible. Online sites that sell RO units (not hydro stores, they are too overpriced, etc.) usually also sell cheap TDS pens for about $25 US. Make sure you get one capable of measuring to 4 digits, not three (9999 instead of 999). Good luck, and I agree with Mace that a TDS pen is very useful in assuring a successful and trouble free grow.

[bbillysbob420]

Quick question about this nute situation that I am trying everywhere to figure out... im sure someone can help me. If using RO water or pure distilled and mixing nutes up will the pH balance itself out? also what is the recommended pH for both veg and flowering? it seems as of right now with mixing the nutes with pure distilled water with a tds of 001-003ppm comes out to 6.0 on the dot. I was reading somewhere that when you start flowering you want to drop it down to 5.5-5.6... just wanted to make sure this information is correct before changes are made. system is an ebb and flow.

[bbillysbob420]

Also u might have a better clue on this lucas but i was wondering when you switch to 12/12 do you mess with the watering times? ie water more during the day or more often... or should everything stay the same.
Also with an ebb and flow how many times is recommended to water a day and do you water at night or only during daylight hours? Its on a 4 x15min a day now seperated 6 hours apart and it seems alright. Thanks for your time guys and i appreciate and knowledgable input by anyone.

[lazi]

I've done a full grow using lf and the Ph was always in range but the res was huge compared to the lighting, 700 litres and 800watts.

What would be a reasonable ratio of res size to wattage to not have to bother with Ph adjustments during a grow?

[ntstephenson]

Please excuse the shot-gun style response...

-final pH of a nutrient solution mixed in RO will vary depending on what line of nutes and what concentration you are using. You are aiming for an end result of pH 5.2 to 5.6 in the root zone. In DWC, NFT, or constantly flushing systems, this means keeping your res at 5.2-5.6 . The longer it takes the medium to dry out, the more concentrated nutes will become as water evaporates in the medium. Adjust accordingly.

- watering times are medium, humidity, light strength, and plant size dependent. If the medium is nearly dry before the next irrigation, then you are timing it right.

- check out Lucas's excellent thread titled "Starting a Medical Cabinet and Bubbler Principles" here: http://www.cannabis-world.org/cw/showthread.php?t=360 (it's also in his sig line) for basic questions like res size versus light wattage. If you can keep the reservoir sufficiently aerated, bigger is always better in terms of pH stability. If you don't have a remote reservoir located away from the heat of your grow lights, remember that the larger the res, the larger the thermal mass. A 100 gallon res will stay cool longer than a 10 gal res, but it will also be harder to cool once it becomes hot. Hot res in DWC means root rot.

[lazi]

Should have said I was talking about dwc. Was promoting the lucas formula on another forum and got asked if RO + lf could remove the need for Ph adjustments. (Auto top up.) I know it can with a massive res but am unsure what the optimum size would be.

[Lucas]

> What EC range should I aim for to avoid Ph problems.

TDS 900-1400@.7conversion
or
EC 1.3 to 2.0

40 gallons per 1k works reasonably

but you will still need to pH adjust the top up barrel..

for example, if the bubblers are at pH 5.3, and the current feed barrel is at 5.8, when you refil the barrel, set pH to 5.8 again.

its a balancing act between the pH of the bubblers, and feed barrel

you can alter pH UPward by using weaker, lower EC, nutes

but, generally, expect to need a little pH UP to keep GH nutes in the mid 5's pH in RO water

with PBP, expect to need a lot more pH UP than with GH..

flying without a pH meter is possible, but not prudent. Still, you are correct that ranging the EC, will range the pH.. but not enough to be able to get it right without pH UP and a meter.

Lucas

[Glass Man]

Hello Lucas,
I'm still having trouble with my pH crashing to 3.8 , even with a new crop of small plants. They have been planted for about 2 weeks, and in 12/12 for about 3-4 days. I thought I'd figured out the problem, thinking that I just needed to mix the powders seperately and then seperately into the res. It seemed to hold at 6.0 for quite a while after doing that, then when I took a reading yesterday it had crashed again. Could the 12/12 light cycle affect the pH? I'm thinking I need to buy some "pH Up" and try using that to get it back to a healthy level. Is there a cheaper source for raising the pH than the bottled "pH Up" , you know me I like to buy the active ingredient if I can. Do you know what to get and where to buy it at the best price?

Maybe something else is wrong since I've never had to raise the pH before. My well water is usually between 7.5 and 8.0

Any chance the plants just "like" the 3.8 level? Their roots appear healthy right now...... I'm sure that can't be true.

Also, does it sound like this is what I need to try first? Or does it sound like something might be contaminating my system and it needs to be sterilized first? I don't know a simple way to achieve that while it's loaded with plants, I assume there isn't a "simple" way. I haven't used any type of chemical to flush between crops, just a good flushing with plain water. Maybe that wasn't good enough?

Thanks,
GM

[Stone]

Hey, Glass Man...

I had a problem similar to yours a while back. I asked my hydro dealer and since I use GH products she told me to call GH and ask one of their engineers. He immediately came up with a solution. He said the nute tank was hosting acidophiles. These are microbes that require a very acidic environment to flourish and to insure their success they excrete acid into the solution to bring the pH to where they like it. He said the cure was either H2O2 or Florashield and told me that I could add 10 ml. of 3% H2O2 per gallon of nutes.

Give it a try -- it can't hurt. Some people will try to tell you that this will kill all the bacteria in your tank. I say... goforit!!! Hydro, unlike soil, does not need any microbes in the solution. It works fine (and probably better) without microbial activity as all the food is predigested and ready for assimilation by the plants. Microbes are just an added PITA. And, I tell you, my plants have never been better than since I began the treatment with H2O2.

[lazi]

What I'm going for is sort of biobuckets, hold the bio. If nothing else we'll see the difference the absence of good bacteria makes eh? Pump is enough to do about 15 changes per hour. 5000Lph pump and 12 x 20L buckets plus 2 x 30L control buckets. Reason for 2 control buckets is that my original plan was for an airpump and a small waterpump just to keep everything mixed. Buckets in a daisy chain, last bucket pumped into control res. So I ordered 13mm barb fittings. Advice here got me buying a big pump with 19mm outlet so a problem with 13mm pipe. My answer is to have 3 x daisychains of 4 buckets each with a control bucket at each end. Auto top up in the same bucket as the pump which provides the waterfall on the other control bucket.

Still waiting on the barbs and grommets so no testing yet. I'm going to be a good boy and test everything first before starting seeds. Already got 3/4" hose to fit the pump, if there's a res temp problem, 22mm copper pipe fits the hose, will make a moonshine type condenser at the waterfall end and put a fan on it.

[Glass Man]

Thanks Stone,
3% H2O2 is just common hydrogen peroxide, right? Hard to believe such a small amount would kill the microbes. Wish I hadn't drained my res now, oh well I'll just fill it back up and try your reccomendation. That was the cure, huh? Sure sounds simple, I like that.

Peace,
GM

ps Btw, how long does it last? Do you need to add H2O2 more than once?

[Lucas]

The use of peroxide, is a way of adding oxygen to the roots. This makes the roots able to live, so there wont be unhealthy conditions that cause roots to die. One of the favorite foods for small insect larvae is dead roots.

When roots rot, pH drops.

Low oxygen levels, promote root rot, which causes low pH.

Adding oxygen by using peroxide is a very temporary way of eliminating anaerobic bacteria. It is important to also remove the low oxygen levels by system design, such as using bubbles, or ebb flow stategies to insure plentyful oxygen in the root zone.

It is also important to remove algae from they system, as it also becomes food for pests. Algae is caused by light reaching nutrients, as can happen on an ebb flow table that has puddles, or when light hits rockwool. Makes sure no light is reaching nutes. Algae also consumes oxygen, competing with the roots.

Low pH is caused by rotten slimy roots, which are caused by too low oxygen levels in the root zone, such as occurs in deep water culture when the water gets above 68F.

To provide high oxygen levels in deep water, I recommend very high airpump ratios, approaching 1 watt of airpump per 1 gallon of water.

Its more important to track the wattage of airpump power, than the number of airstones. You want serious churning, not just a trickle of bubbles.

Lucas BubbleHead

[Glass Man]

I just changed the nutes. The new solution read 5.8 without any adjustments. I have airstones in my resevoir and my SWC table is completely covered and continuously recirculated via spray nozzles above the waterline. It's the same as it always has been, except perhaps I'm running the water level a little deeper. It's at 1.5" instead of 1/2", I always run it deep in the beginning so the roots stay well submerged.

I added a liter of peroxide to the resevoir. I'll keep a close check on the pH and if it crashes again I'll increase the air and collect a 2-3 gallon sample to experiment with. I wish I'd kept some of this last batch for testing.

Btw, my roots look very healthy. The 3.8 didn't seem to harm them at all. I had noticed before in soil that this cultivar (strain) has done just fine with an extremely low pH while other cultivars were killed by it (I was a newbie and didn't add lime to my mix).

Hopefully this pH crashing won't happen again, but if it does I'll have a better idea of how to deal with it.


Thanks,
GM

ps This all just reminded me that I have a large oxygen tank in my glass studio which would be just the deal for cranking up the oxygen level !!

[tjhidro]

hey lucas...
i first ran across your formula back on OG, and used it with a NIMBLY STEALH 150 hps cab setup, and boy it was great!!! I have done tons of searchs through the years on your formula...only to get second hand info.. It is excellent to finally get to pick your mind!!!
unfortunitly, dureing your absense, i have aquired a BOATLOAD of pbp nutes and additives...While my stealth cab grows were great, they have steadly gone down, and my next grow i am going BACK TO BASICS.
i will be useing a ebb and flood with gh micro and floronovabloom ONLY...
(anyone want to buy a line of pbp nutes and additves???)
My question is.....
in ebb and flood....would it be better to plant directelly in the tray in hydrocorn, or use say use 6in square planter?
Allso...if useing the planters does one place a little hydro corn in the bottom of it then the clone, or just set the clone in and fill with hydrocorn???
Thanks a lot...reading through this forum has answered a ton of questions of what i have been doing wrong....I.E...more is not better....

good luck good grow tjhidro

Hey LUCAS i got a qustion for ya ...i am growing a tomatoe plant, yes a real live tomatoe plant in my grow box... and its growing but dont look right what is the best nute profile for it or is the 8 mll right for it as well as MJ.. not shure what wroung with it but the leafs look like it has blister on it and some yellow spots not shure if it needs more calacum or not... and yes pepole dont flame me for doing this i got all the smoke i need for a long time so why let the box go un used... and my gf will get use to me growing house plants and wil soon be bore with it and i will start up some chem? x c-99.

new ganjaboi grow box
150watts hps soon to be cooled tubed
6 gal rubbermiade swc
FN-GROW and BLOOM NUTES
tds is 1400
ph 5.8 -6.0
tap water 40 ppm ph 6.8
rez temp is 68 to 72

[Lucas]

> Allso...if useing the planters does one place a little hydro corn in the bottom of it then the clone, or just set the clone in and fill with hydrocorn???

yes

the transplant should not be buried deeper than it was, just barely cover the rockwool cube, if that was the cloning medium

> the leafs look like it has blister on it and some yellow spots not shure if it needs more calacum or not

I think your nutes are strong enough

you might benefit from more bubbles, does your system use an airstone.. it should

Lucas

[DOZEE]

how you been man.. didnt know your still here LUCAS

yes i run 2- 6" air stone's.. water level is abou a 1" below the net pot but notice that some of the leafs eges are curling up ward and getting on the crispy side wile some leafs tips are curling under my tds after topping with plain tap water was 1450 and a ph of 5.8 and check 24 hours later had to add a 1/2 gallon tap water and then my tds was 1027 and a ph of 4.6 she keep taking every thing i give her...i up the tds to 1900 last nite not shure if that will help or make it worse got anouter tomatoe plant in a flood and drain and my tds is way about 2000 but i cant check any more cuz my meter only goes to 2000 but it dont have the blister leafs they just trun brown at the tips and rot off one queation is flornova and the gh flora series made just for MJ or is it good for all plants?

[Glass Man]

It's probably a lot less expensive to just buy tomatoes than to use HIDs and GH nutes, but "homegrown" tastes better.

Here's some info specificly for growing hydro tomatoes. Can't find the www address, but just google this: University of Florida IFAS Extension - Nutrient Solution Formulation for Hydroponic (Perlite, Rockwool, NFT) Tomatoes in Florida. Written by George J. Hochmuth and Robert C. Hochmuth

It's a bit "techy" but if you read through it a bit you'll figure out exactly what the pro's use for growing lots of hydro "maters"!!

Maters do have different nutrient requirements than Cannabis.

Btw, try sautee'ing some green maters or stir-fry some. Yum yum!



peace,
GM