Ask Lucas

[Lucas]

> What would be the ideal temp/humidity to keep this room at with the parameters above?

check post 151 line 11:-)

Lucas

[webfish]

Grumpy old man!!!how the hell are you my friend??Im so glad to see your in there fighting the good fight..keep it up and take care of your self...

[Lucas]

welcome home old buddy

dont believe the grumpy front, Im really just a teddy bear <g>

this buds for you
Lucas

[otis]

hey lucas...

great thread!

i would love to ask you your thoughts

after years of soil growing, i am coming back to hydroponic.

my new set up is as follows...

2- 600wt hps for a 3 x 6 tray... 18 "2 gallon" pots filled with hydroton with 1 inch rockwool cube starters (medical club clones)

fed by drip (run to waste)

i was planning on having the pump cycle several times while the light is on
(on for a 1/2 hour, 3 times during the light cycle)

any advice or suggestions?

thank you so much for your time

-otis

[OldSog]

having a similar setup, i found that dripping 30min on/15min off was great.
24/7 worked well but sometimes the drippers would clog. you'll go through alot of nutes doing s "run to waste" any reason why you're not using a rez and recirculating?

for me, if i were to use a run to waste system it would be with coco/perlite or soil, which is what i'm doing because of the heat.
run to waste using growrocks will cost you alot more in the long run.


peace,

[suzy cremecheese]

I can't imagine the water bill.

[otis]

hey SOG...

good to see ya!

anyhoo, the reason for the "run to waste" is to keep the PH nice and stable
"same as it ever was" so to say..

a fellow grower i know runs a "run to waste" simular setup with rockwool stacked small to large, pyramid style, and has the pump cycle 2 times for 30 minutes (once when the lights come on and the other a hour before they shut off) and he has great results....

i would like to use hydroton rock (with 1 inch rockwool starter clones) instead to be able to have more air get to the roots in the 2 gallon buckets and not have the medium be as wet for such a long period of time.

last time growing in hydro i was running the same kinda setup with a recirculate into the rez and i didn't like to keep on fiddling with the nute ratio/ph down etc.

as far as nute and water cost, well i dont think it costs that much...

the water bill is about 30 bucks a month and gh nutes are easy to come by in the bay area for a good price...

[Lucas]

> the reason for the "run to waste" is to keep the PH nice and stable

would you be willing to recirculate instead of running to waste, if I told you how to keep your pH stable? (by keeping the reservoir topped up with water and nutes to original TDS of a fresh res)

as to the question of watering frequency in rox, and btw, I like your intent to top water, I agree with OS that you could run 24/7..

you need to determine the watering needs in rox based on how fast they dry out.. my guess would be to water for 15 minutes every 2 hours of lights on, plus one irrigation during the dark cycle.. but, that depends on whether your pots dry out, or dehumidify, during the dark period..

Ive used the Lucas formula for several years now. PH wander has not been an issue. Res sizes have ranged from 10 to 50 gallons.

The key Ive found in following Lucas's suggestion is to start the res at about 5.3, allow it to drift up normally to ~6.1ish..and it will then drift back down to around 5.5. Proper topping off allows the res to be VERY stable within the proper growing PH range with very very minimal effort... hr

[otis]

lucas...

thank you for responding to my post!

my last adventure in hydroponic growing was the same set up with a 25 gallon recirculating res.

i would top the res with tap water and add some PH down to keep it 5.8 to 6.5... years later after speaking with other growers still doing hydroponic while i did soil, i found out that my PH was running high.

the problem i see with the 24/7 drip in ongoing salt build-up clog in the 1/4 inch drip line and the roots never having a chance have some air flow.

last hydro grow, i watered during the light cycle only.

i gave up hydro last time due to several factors

1) i was yielding less and less every harvest with a poorer quality product, i think this was a problem with heat build-up in my small growroom and a problem with PH flux.

2) i lived on the 2nd floor of a old victorian and even though my neighbor who lived downstairs was cool, he was pretty bummed the 3 times i flooded him thru the cealing.

soo...

i would like to know (or have you tell me where its posted) how to keep my PH stable in a recirculating res.

my current res is a 20 gallon rubbermaid "brute" trashcan

[otis]

oh...
thanks hydrorascal!

[mace]

otis,

res size and the water you use also makes a big difference, tap water for instance contains calcium, it will make the pH rise towards 8ish when air is bubbled trough.
Thats a fight that cannot be won with pH down better water or nutes for hard tap water are possible answers.

The bigger the res, the more stable are things, including temps, EC, pH...

gl,

mace

[otis]

thanks mace...

san francisco tap water is remarkably good, so i am not too worried about that, but i might upgrade to a larger res....

Hey Lucas, what's your opinion on flushing? Using your formula 0,8,16 for bloom I usually switch to straight water for the last 2 1/2 weeks of bloom. Good or bad idea? TIA

Kurious

[Krink]

Great read so far...but I am a little curious on some things.

I grow in a coco/perlite and some are in coco/hydroton. Some are in bins without drain holes, and recently I started using 2G grow bags, with lots of drain holes.

I was having a real problem of slow growth in veg stage. So I read somewhere that for coco, you should water alot...don't let it dry out. So I started watering daily based on how much the plants drank that day. I use a moisture meter to see how much they have drank. If it looks as though they are still fairly wet....then they only get 200ml of water. I feel giving just a bit of water, even if they are still wet sends more oxogen into the root zone. If the plants have drank a fair amount(I find the coco/hydroton mix to dry out quicker), then I water based on your previous statement of imagining how much of a pitcher would be used up by stuffing the plant in the pitcher.

This has resulted in a huge turn around in performance for my plants...which of course means I'm keeping them wet. I think coco is the one soiless exception for keeping the medium wet. Since reading this thread a few weeks back I also implemented a 1/3 strength of FNB for 3 daily waterings, then a watering of straight water. I haven't been using a tds meter to this point, cause I didn't own one. My new one came in the mail today, so I intend to start reading what my strengths are.

Also..I recently got a ph meter pen. I was trying to get the ph of my 2G of nute solution( alfalfa tea with silica blast, humic acid and molasses) down as it was reading 7.2. I added 3 tbs of gh ph down, and it would only go to 6.9. How much of ph down can you add before you screw things up? I have never used ph up or down before...so I didn't want to kill anything. Any tips on raising and lowering ph would be great.

C an you believe that keeping my coco wet without drain holes can be done successfully?

Cheers,
Krink

Quote:

Originally Posted by Kurious

Hey Lucas, what's your opinion on flushing? Using your formula 0,8,16 for bloom I usually switch to straight water for the last 2 1/2 weeks of bloom. Good or bad idea? TIA

Kurious

I'm not Lucas but I have to say flushing that early will hurt yield slightly IME, those buds are still fattening up. I find 7-10 days of straight water plenty to bring out the plants true unadulterated flavor. I'm pro flush BTW

Thanks Dycans, I'll leave the nutes in the tub a little longer.

Kurious

[Lucas]

> the problem i see with the 24/7 drip in ongoing salt build-up clog in the 1/4 inch drip line and the roots never having a chance have some air flow.

I dont agree that constant flow causes salt buildup, I think it does just the opposite. I think of constant flow as constant flushing, so the medium is never holding more nutes than the reservoir.


> how to keep my PH stable in a recirculating res

keep the res topped off with water, I agree bay area water is as good as RO water

add nutes to the res on a regular basis, weekly is often enough, to bring the TDS back up to normal levels of a new res.

during water addbacks, TDS will fall, and pH will rise

after nute addbacks, TDS will rise, and pH will fall

if the res is not draw down more than 10% of its volume between refils, the pH wont go too low, and the TDS wont go too high, between reservoir topp offs

> what's your opinion on flushing?

Im for it if the medium accumulates nutes, but prefer a system that does not allow that

watering grorox with ebb flow or 24/7, will not require flushing, IF THE NUTES ARE NOT ALLOWED TO CONCENTRATE BETWEEN RESERVOIR TOP UPS.

iow, flushing is for systems that allow the TDS in the medium to rise above the TDS of the res. For reference values, I think flushing is unnecessary if TDS is not above 1400 in the root zone, AND there is no excess Nitrogen in the chosen fertilizer..

otoh, if the nutes include a lot of ammoniacal Nitrogen, AND the irrigation strategy allows the TDS in the root zone to rise above 2000 TDS, then flushing would be beneficial.

I dont agree in plain water for ebb flow or dwc, but do agree in plain water IF a dense medium like Coco has been overfetilized over time.

> I feel giving just a bit of water, even if they are still wet sends more oxogen into the root zone.

disagree, in medium, the primary oxygen delivery comes from the humid pores in the medium. Watering, closes those pores, and until the plant consumes the water, atmosphere cannot enter the pores. It is the atmosphere in contact with the humidity in the root zone, that delivers oxygen to plants in dense mediums like coco. I do not agree that coco can be kept wet all the time.

> If the plants have drank a fair amount(I find the coco/hydroton mix to dry out quicker), then I water based on your previous statement of imagining how much of a pitcher would be used up by stuffing the plant in the pitcher.

> This has resulted in a huge turn around in performance for my plants...

that is very gratifying.

I think you have mastered the art of watering

> it would only go to 6.9. How much of ph down can you add before you screw things up?

your nutes lack Nitrogen maybe, which would produce a much lower pH. My TDS comments refer to GH nutes, that have known NPK levels that approximate the mel frank guidelines on pH's website.

too much pH down is, imvho, anything more than 3ml per gallon, total. iow, if you add the equivalent of 60ml of pH down to a 20 gallon reservoir, even if that happens over the course of 3 weeks, adding just 1ml per gallon of pH down per week.

Im refering to 9% Phosphoric Acid, and the pH down concentration. Thats standard GH pH Down.

if you dont use a GH nutes profile, its possible to use more pH down without harm, if your nutes are low in P to begin with. GH is NOT low in P. Pure Blend is low in P.

hard tap water is problematic, over 200ppm, it will raise pH, forcing the use of potentially too much P as pH down.

that means Pure Blend will tolerate tap water better than GH nutes

you would need to use pH's spreadsheet to know what your particular nutes are providing in NPK elemental values

> C an you believe that keeping my coco wet without drain holes can be done successfully?

absolutely! Congratulations! You have mastered the Art of Watering, by letting your pots breathe between irrigations. This comment applies to Coco.

In 24/7 top irrigation of a 2 gallon pot of grorox, there is so much pore space, that a dry cycle is not required.

the reason I speak of 24/7 irrigation of a 2 gallon pot of rox, is because the rox will be mostly above the water line of an ebb flow table. The goal is to get roots to grow in the whole rox volume, not just in the bottom 4" that an ebb flow irrigates.

thanks for all the dialogue and participation from everyone posting to this thread

Lucas

[otis]

lucas...

how does this sound?

i keep a seperate 20 gallon rubbermaid "brute" trashcan filled with pre-mixed nutes and add to the res as it drops..

yes-no?

[Lucas]

> i keep a seperate 20 gallon rubbermaid "brute" trashcan filled with pre-mixed nutes and add to the res as it drops.

it might be too strong to add full strength nutes, you may only need half strength in the addback

whatever addback strength brings the full res back to TDS target is good

[otis]

thank you so much lucas!

i will keep everyone posted on how the new grow setup works out...

[Indica Sativa]

Lucas, any tips or thoughts on foliar feeding?

[Lucas]

> foliar feeding?

it works like mainlining... that means hypodermic injection into a vein

iow, foliar feeding goes directly into the bloodstream

it is easy to over feed that way

Im against it. If the plants are being properly cared for, mainlining wont solve the problems.

Instead figure out how to feed the root zone properly, the way nature does.

Some of the reasons Im against foliar include
1. it can cause a lamp to explode if the spray hits it
2. it adds nutes to the already present nutes in the root zone, allowing for a potentially dangerous overfeeding
3. it allows water spots to magnify the light and cause leaf burns
4. it allows nutrients to dry onto the leaf surface, interfering with healthy leaf surface behaviour
5. it allows for mold to start in a dense bud structure

Do not foliar feed in the dark, that will invite powdery mildew

imnsho do not foliar feed, why would you want to?

the plants will grow like gangbusters in a properly fed system, why would you want to invite mold, mildew, leaf burn, and why would you want to coat your buds and leaves, which will later be smoked, with substances that are not cannabinoids

just my opinionated opinion

Im sure many people do it, and get away with it, especially if they wash the leaves off with plain water after foliar feeding

why would you want to smoke nutrients?:-)

Lucas

[Indica Sativa]

Quote:

> should I raise the temps to get the pots to dry quicker?

no
you should lower the humidity in the room, to 30%, then the pots will dry out nicely

no point boiling the roots after drowning them..

let them breathe, dont make too wet, too hot

feel the cool breeze blowing nice fresh air through the room

How do I go about flushing, if I am not able to drop the humidity in my environment? I am not able to get a dehumidifier for a couple more weeks. Current rh fluctuates between 56-68%.. temps are 73 at night and about 78 during mid day. I tried flushing the medium (50/40/10 coco/perlite/hydroton in 3 gal pot) the other day and it seemed to devastate them. I did measure the run off from one of the pots.. pH was 6.2.. EC was 1.5.. Are there any coco masters I might be able to PM and ask a few questions? Lucas would ya mind if I posted pics of my plant problem? Thanks for the help and the foliar info =]

Aditionaly, foliar nitrates become an cancering agent. Small quantities, but if used continously...

Indica Sativa, im not a master, but i can share my experience growing in coco coir (similar mix than yours). Currently i dont flush (just the preharvest), ive notice bad reactions when flushing, but i grow in e&f.

The run off ph is fine, and the EC is high, but dont worry unless your plants ask for flushing. Coco coir have a high EC, i only needed to flush when run off EC reach 2,5. If you feed correctly, likely it wont happen.

I know this isnt what many gurus says, but it works for me.

Lucas, i have a question. I choosed to add a dilution of SO4K2 (potash sulphate), because my nutrient profile is low in K and S (we disscused it before) and, by the way, help to low the nutrient ph without acids (the SO4K2 dilution have a ph of 4). Its the only potash compound i know that is acid. But ive think that maybe when in the solution the potash sulphate can react and affect strongly the ph. Probably i dont know it until i try, but anybody has experience using SO4K2?

knna