Get a Harvest Every 2 Weeks

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LoudBlunts

Well-Known Member
al, what is the importance of keeping water temps down?

do you control your the temp of the water in all of your res'?
 

Al B. Fuct

once had a dog named
Ok thanks for the help. Figured I'd try a 50/50 mix for a start then go from there.
Sounds like a plan. Let me know how you go. :)

al, what is the importance of keeping water temps down?

do you control your the temp of the water in all of your res'?
High water temp, above about 26-27C, will reduce the dissolved oxygen capacity of the water.

I don't control my res temps. My roots are not dangling in the res. Moreover, I feel no need to check them as there's no way for my tanks to get any warmer than the air temp. The air from the very small, rubber diaphragm type (as opposed to piston type compressors which do generate a fair amount of heat) pumps is not appreciably warmed nor do my also very small water pumps introduce any significant amount of heat, given they are only running between 6 and 10 total minutes per day, in two runs.

Water temp measurements are not terribly necessary in flood systems given the thermal dissipation capacity of already damp absorbent media and other factors like the tanks being below the trays, shielding them from direct light exposure. However, temp control can be critical in NFT, DWC or aero systems where the roots are constantly exposed to a flow of nutes from the res and where larger air and water pumps or exposure of the nute reservoirs to light may introduce a significant amount of heat to the nute solns.
 

panhead

Well-Known Member
I trim off all branching, not just leaves, on the lower 1/3 of the plant. I do this twice, once at the end of wk1 of flowering and again sometime around the end of wk3. The idea is not to allow any branches more than about 1" long.

After wk4, the plants usually stop any vegetative growth; they stop growing vertically and stop sending out branches, instead just bulking up the flowers.

You're basically growing a single stalk with buds attached directly to the mainstem. Fan leaves which are above the lower 1/3 should be preserved as much as possible. These are the plant's solar powered food factories and it is in your interest to keep them going as much as you can up to harvest.
Hi al,dig this,i know you trim everything including fan leaves on the lower 1/3rd of the plants & ive read your reasoning for trimming the fan leaves also, but i ask is trimming the fan leaves really nessacary,in my rooms ive went to great lengths to emulate your system only using soil,ive also went to great lengths to control humidity,circulation & temp's,here's what im getting at,i can keep my rooms temps at a constant 72 to 80 degrees at the canopy or any temp in between,i can also hold the humidity levels at the canopy to 40% & at the plant base to 50% without even using the dehumidifier's.

With me being able to keep the humidity levels this low & stable & still be able to lower the humidity level even farther by running the dehumidifiers would you think leaving all the fan leaves will benifit the plants growth & flowering.

So far ive been trimming everything including the fan leaves on the lower 1/3 rd of the plants but reading your last few pages about why you do this got me thinking,if i could save these lower leaves without creating a humidity problem that it might be a great benifit.

Btw,i check my plants every other day when i visit the garden for mites,powdery mildew & bud rot.
 

Enigma

Well-Known Member
Very good information here.. the trimming of the plan about a 1/3 of the way up is critical as they will be "stealing" nutes from the plant where than can be better used. Unless of course you have supplimented light to the sides of the plant.
 

LoudBlunts

Well-Known Member
Sounds like a plan. Let me know how you go. :)



High water temp, above about 26-27C, will reduce the dissolved oxygen capacity of the water.

I don't control my res temps. My roots are not dangling in the res. Moreover, I feel no need to check them as there's no way for my tanks to get any warmer than the air temp. The air from the very small, rubber diaphragm type (as opposed to piston type compressors which do generate a fair amount of heat) pumps is not appreciably warmed nor do my also very small water pumps introduce any significant amount of heat, given they are only running between 6 and 10 total minutes per day, in two runs.

Water temp measurements are not terribly necessary in flood systems given the thermal dissipation capacity of already damp absorbent media and other factors like the tanks being below the trays, shielding them from direct light exposure. However, temp control can be critical in NFT, DWC or aero systems where the roots are constantly exposed to a flow of nutes from the res and where larger air and water pumps or exposure of the nute reservoirs to light may introduce a significant amount of heat to the nute solns.
so with that said...do you have a cheap alternative to chillers?
 

jaytee211

Active Member
great setup...im trying to build a similar setup so i have a few questions:
how many gallons are necessary for a 3' x 3' tray?
what do you recommend for watering cycles for the first few weeks up until harverst?
how many airstones or bubble wands are needed in the reservoirs for a 3' x 3' tray?
 

Al B. Fuct

once had a dog named
i ask is trimming the fan leaves really nessacary,
[...]
With me being able to keep the humidity levels this low & stable & still be able to lower the humidity level even farther by running the dehumidifiers would you think leaving all the fan leaves will benifit the plants growth & flowering.
[...]
So far ive been trimming everything including the fan leaves on the lower 1/3 rd of the plants but reading your last few pages about why you do this got me thinking,if i could save these lower leaves without creating a humidity problem that it might be a great benifit.
If your plants are anything like mine, the fan leaves attached on the lower 1/3 of the mainstem would account for 4-6 leaves. I haven't tested the theory but I'll take a punt and suggest that preserving 4-6 fan leaves vs the potential restriction in airflow isn't a good trade. I think there's a greater benefit to all plants in improving air circ than what each will gain by preserving 4-6 lower fan leaves.

Keeping a broad air path open beneath the mass of buds, restricted only by the stems, gives a nearly direct path for air from circ fans to get to all parts of the flowering mass. Ideally, you want to see circ fans make every leaf in the room flutter once at least every 30sec or so.


Very good information here.. the trimming of the plan about a 1/3 of the way up is critical as they will be "stealing" nutes from the plant where than can be better used. Unless of course you have supplimented light to the sides of the plant.
Thanks for the thanks. :)

I don't think that the nutrient usage is as big an issue as the air circ restriction of leaving the lower fans on.

Supplementary light isn't generally useful. Hanging CFLs or common tube fluoros beside overtall plants which are lighted from above with HPS is a bit like bolting a model airplane engine on the front bumper of your Ferrari. If the plants are so tall or dense that lower areas are suffering from low light, they haven't been pruned sufficiently or they were vegged before flowering. If a clone is just chucked from the clonebox in to the 12/12 area with no veg time in between, it will find its own best height by wk4. That finishing height will depend on the size of the lamp used for flowering. 1000W HPS lamps produce plants which finish about 33-36" (1m) tall, stopping gaining all their vert height in wk4 of 12/12.

so with that said...do you have a cheap alternative to chillers?
yeah... ice cubes!
DUUUUHHHHH!!
Well, heh, there you go. :D

Me, I'd be tempted to put a 8-10m long coil of 1/2" copper or aluminium tubing in an old bar fridge or tuckerbox freezer and pump nutrient soln through it and back to the res. That'd cool it! A thermostat with a remote sensor in the nute soln could switch the bar fridge on & off as needed.

However, I've seen Peltier effect coolers in the past, intended for fitting through the wall of a res tank, which I strongly suspect would be more efficient than a loop of copper tube in a bar fridge, certainly mechanically simpler.

If your res tanks run too warm, work out how the heat is getting in them and try to break that path. You may need to get pumps that permit mounting outside the res so that their motors cannot be in contact with the nute soln. Tanks can be insulated against exposure to direct light with pandafilm. If the thermal path is via very warm air temps caused by lighting, you'll be looking for a way to get those air temps down- cooltubes are very cost effective.

great setup...im trying to build a similar setup so i have a few questions:
how many gallons are necessary for a 3' x 3' tray?
what do you recommend for watering cycles for the first few weeks up until harverst?
how many airstones or bubble wands are needed in the reservoirs for a 3' x 3' tray?
My trays are pretty close to 3'x3', just a tick smaller (820mm^2). Each tray has a 125L (33 gal?) tank. When the trays flood (flood level 50mm), about 1/4 - 1/3 of the 125L tank volume is up in the tray. The volume of the 820mm x 820mm x 50mm flood area is 33.62 litres.

Your watering intervals will depend on a few factors; the media you're using, air temps and how effective your ventilation system is. If you have
a mountain of ventilation capacity, you may find that the increased evaporation causes a need for more watering cycles.

Of course, you'll only need to water during lights-on. With Fytocell media, I find I can flood the flowering plants 2x per lights-on cycle, at lights-on and again 2 hours before lights-off. My flood cycle durations vary as I have different sized pumps. Takes about 3-5 mins for a tray to be filled to the overflow tube level, depending on the pump in that particular tank. The small, cheap pumps are of course the slowest.

Flood systems can tolerate loss of tank aeration a lot better than DWC or similar systems, so a redundant or hot standby air pump and stone probably isn't necessary... 1 pump and stone per tank will do.

However, I would strongly recommend that you keep a couple spare air pumps (or replacement diaphragms/flapper valves for rebuilding) on hand for the day that the one you're running now craps out. The diaphragms in these cheap pumps are usually natural rubber, which will dry-rot and perish in about 12-18 mos of continuous service, or faster if there's an ozonator in use in the area. O3 will advance rubber dry-rot dramatically.
 

potroast

Uses the Rollitup profile
It'd be a pretty good guess to say that the sort they sell and hence the sort I have is 'absorbent.'

I'll look into sourcing some repellent type floc and have a try. :)

I remember hearing about some kinds of rockwool used for construction, maybe insulation, and that you shouldn't use it for hydro. First off, I'd want to know what they put into it to make it repellent.

HTH :mrgreen:
 

bigal10

Active Member
do you think someone needs to set up a A/C unit. I am considering buying a portable AC unit at the hydro store. :blsmoke:
 

Al B. Fuct

once had a dog named
I remember hearing about some kinds of rockwool used for construction, maybe insulation, and that you shouldn't use it for hydro. First off, I'd want to know what they put into it to make it repellent.

HTH :mrgreen:
Good point, pottie. However, the Grodan product is marketed for horticulture, not building insulation. I would hope there's nothing bioactive in it. Wouldn't hurt to get a look at the MSDS for the product.

300W Titanium Aquarium Heater Digital Controller MX1000 - eBay (item 380004113039 end time Mar-12-08 20:00:00 PDT)

alternative al?

im not sure....but im kinda puzzled on how an aquarium heater can keep things around 64F (rough estimate of 18c)

what you think? worth a shot?
Dunno, do you need to heat or cool your tank? This device is a thermostat for a heater.

This is the Peltier Effect (PE) cooling device I was talking about. PE devices are stacks of semiconductor material that have the ability to move heat directionally from one side of the device to the other, depending on the direction of DC current flow. If you reverse the current to the IceProbe, it will warm the water. I'd inspect the specs for the device closely before investing in one. Find out how much water it can be expected to cool. Get ready to go back to your HS science to work out how many joules you need to shift to get the temp you want.

The bar fridge & metal tubing coil thing may not be so nutty when you figure the IceProbe consumes only about 50W and costs about $USD110. I bet I could shift a lot more joules through the bar fridge and I bet I could get an old one for about the price of the IceProbe. I could cool another tank with a second coil in my old fridge.

do you think someone needs to set up a A/C unit. I am considering buying a portable AC unit at the hydro store. :blsmoke:
If you're going to get a portable AC unit, get a split system type that has a compressor unit that goes outside (or at least outside the grow). These are HUGELY more efficient than the one-piece portables that duct waste heat out a window through a dryer-vent sized (120mm) flex hose. Most newer 1-piece portables recycle their condensate to improve cooling, some give you a way to add distilled water. If you look at a 2nd hand unit, assure that tap water was never used in the unit. The minerals will crust up the evaporator and make it useless. The cheapest and most effective 'portable' aircon units are the old standard window mount types.
 

Al B. Fuct

once had a dog named
One note about A/C- conventional wisdom says it sucks a lot of power and is very expensive to run. Ya know what? Conventional wisdom is spot on. A/C is a LAST RESORT measure and portable A/C units are the very last in your line of options. The least efficient single unit portables would be working hard to cool a grow with a non-cooltubed 400-600HPS. A/C becomes your only choice when the air you can draw in is already hotter than your 24-26C range, such as is the lot for the poor sods in Queensland, Tejas and S Cowlifornia.

Cooltubes are a big bang for the cooling buck and should be considered long before A/C. If you can get intake air no warmer than 23-24C, run cooltubes, locate ballasts outside the room's airmass and have otherwise adequate ventilation, you stand a pretty good chance of maintaining the 24-26C range, even in a fairly small (500cu ft) room running a couple 1000W HPS.
 

cmak40

Well-Known Member
One note about A/C- conventional wisdom says it sucks a lot of power and is very expensive to run. Ya know what? Conventional wisdom is spot on. A/C is a LAST RESORT measure and portable A/C units are the very last in your line of options. The least efficient single unit portables would be working hard to cool a grow with a non-cooltubed 400-600HPS. A/C becomes your only choice when the air you can draw in is already hotter than your 24-26C range, such as is the lot for the poor sods in Queensland, Tejas and S Cowlifornia.

Cooltubes are a big bang for the cooling buck and should be considered long before A/C. If you can get intake air no warmer than 23-24C, run cooltubes, locate ballasts outside the room's airmass and have otherwise adequate ventilation, you stand a pretty good chance of maintaining the 24-26C range, even in a fairly small (500cu ft) room running a couple 1000W HPS.
hey al i got air comin fresh from out side and headin back out, i do have cooltubes available but i live in the north and temps go from -10c in winter to +30c in summer. will really good circulation b good enuf to keep the temp kind of stable? i dunno if i should use the cool tubes because its cold rite now and the room could get probably down to 10-14c at nite with no light on.
 

Al B. Fuct

once had a dog named
hey al i got air comin fresh from out side and headin back out, i do have cooltubes available but i live in the north and temps go from -10c in winter to +30c in summer. will really good circulation b good enuf to keep the temp kind of stable? i dunno if i should use the cool tubes because its cold rite now and the room could get probably down to 10-14c at nite with no light on.
I can make some general suggestions but without seeing your op in entirety, it's hard for me to tell you what your ultimate solution is.

If you are keeping your temps bang-on between 24-26C in your winter, you can do without cooltubes. However, when summer comes for you, your conditions will probably change.

I'm going to be in your boat in about 3.5 months. The ambient air available to draw into my op drops to as low as 10-12C. I will be adding "Y" pipes to the inlet and exhaust from my cooltubes. With the appropriate air path for the season blocked off, the Y pipes will permit either sourcing and dumping air outside the op (as it is now in my summertime) or sourcing and dumping air within the grow op airmass to provide heat to keep the room above 16-18C.

I rely on my dehumidifier to add a little bit of heat to the room during lights-off in winter. Keeps the lights-off temp at least above 16C.
 

stickyicky77

Well-Known Member
If your plants are anything like mine, the fan leaves attached on the lower 1/3 of the mainstem would account for 4-6 leaves. I haven't tested the theory but I'll take a punt and suggest that preserving 4-6 fan leaves vs the potential restriction in airflow isn't a good trade. I think there's a greater benefit to all plants in improving air circ than what each will gain by preserving 4-6 lower fan leaves.

Keeping a broad air path open beneath the mass of buds, restricted only by the stems, gives a nearly direct path for air from circ fans to get to all parts of the flowering mass. Ideally, you want to see circ fans make every leaf in the room flutter once at least every 30sec or so.




Thanks for the thanks. :)

I don't think that the nutrient usage is as big an issue as the air circ restriction of leaving the lower fans on.

Supplementary light isn't generally useful. Hanging CFLs or common tube fluoros beside overtall plants which are lighted from above with HPS is a bit like bolting a model airplane engine on the front bumper of your Ferrari. If the plants are so tall or dense that lower areas are suffering from low light, they haven't been pruned sufficiently or they were vegged before flowering. If a clone is just chucked from the clonebox in to the 12/12 area with no veg time in between, it will find its own best height by wk4. That finishing height will depend on the size of the lamp used for flowering. 1000W HPS lamps produce plants which finish about 33-36" (1m) tall, stopping gaining all their vert height in wk4 of 12/12.





Well, heh, there you go. :D

Me, I'd be tempted to put a 8-10m long coil of 1/2" copper or aluminium tubing in an old bar fridge or tuckerbox freezer and pump nutrient soln through it and back to the res. That'd cool it! A thermostat with a remote sensor in the nute soln could switch the bar fridge on & off as needed.

However, I've seen Peltier effect coolers in the past, intended for fitting through the wall of a res tank, which I strongly suspect would be more efficient than a loop of copper tube in a bar fridge, certainly mechanically simpler.

If your res tanks run too warm, work out how the heat is getting in them and try to break that path. You may need to get pumps that permit mounting outside the res so that their motors cannot be in contact with the nute soln. Tanks can be insulated against exposure to direct light with pandafilm. If the thermal path is via very warm air temps caused by lighting, you'll be looking for a way to get those air temps down- cooltubes are very cost effective.



My trays are pretty close to 3'x3', just a tick smaller (820mm^2). Each tray has a 125L (33 gal?) tank. When the trays flood (flood level 50mm), about 1/4 - 1/3 of the 125L tank volume is up in the tray. The volume of the 820mm x 820mm x 50mm flood area is 33.62 litres.

Your watering intervals will depend on a few factors; the media you're using, air temps and how effective your ventilation system is. If you have
a mountain of ventilation capacity, you may find that the increased evaporation causes a need for more watering cycles.

Of course, you'll only need to water during lights-on. With Fytocell media, I find I can flood the flowering plants 2x per lights-on cycle, at lights-on and again 2 hours before lights-off. My flood cycle durations vary as I have different sized pumps. Takes about 3-5 mins for a tray to be filled to the overflow tube level, depending on the pump in that particular tank. The small, cheap pumps are of course the slowest.

Flood systems can tolerate loss of tank aeration a lot better than DWC or similar systems, so a redundant or hot standby air pump and stone probably isn't necessary... 1 pump and stone per tank will do.

However, I would strongly recommend that you keep a couple spare air pumps (or replacement diaphragms/flapper valves for rebuilding) on hand for the day that the one you're running now craps out. The diaphragms in these cheap pumps are usually natural rubber, which will dry-rot and perish in about 12-18 mos of continuous service, or faster if there's an ozonator in use in the area. O3 will advance rubber dry-rot dramatically.
The coiled copper in the nute tank that you are referring to for a chiller is used in brewing ALE. It is called a wort chiller and a premade one and can be purchased at a brew supply shop. How they are used in brewing beer is that the 3/8 coiled copper tubing is put into the vat of beer wort and chilled water is circulated through the copper. The water circulating through the copper acts as a refrigerant medium and removes the latent heat form the beer wort to cool it quickly. It would work the same for your nutes. My 2 hobbies are brewing Ale and growing ganja. Hops Beer Wine Brewing Supplies Equipment and http://www.strandbrewers.org/techinfo/ Hopefully one day i will find a way to combine the two and make a super ganja brew.. lol.
 

Al B. Fuct

once had a dog named
The coiled copper in the nute tank that you are referring to for a chiller is used in brewing ALE. It is called a wort chiller and a premade one and can be purchased at a brew supply shop. How they are used in brewing beer is that the 3/8 coiled copper tubing is put into the vat of beer wort and chilled water is circulated through the copper. The water circulating through the copper acts as a refrigerant medium and removes the latent heat form the beer wort to cool it quickly. It would work the same for your nutes.
Cool! That wasn't exactly what I had in mind, but it's pretty darn close. I was thinking about pumping the nute soln itself through a coil of tubing which had been placed in a fridge, instead of placing the coil in the nute soln. Thought about 1/2" tubing as that's the ID of most aquarium pump outlets and garden hose.

The wort chiller would pretty obviously do the same thing, but not circulating the nutes, rather an intermediate coolant soln. I think it may be more somewhat more efficient to directly cool the nute soln rather than exchange heat with a coolant soln, but surely either would work.
 

LoudBlunts

Well-Known Member
so on a 1000watter what cfm size fan do you recommend?

i used to use a 4" on her....i think it was somewhere around 200cfm, do you think i should upgrade if im in hotter climates? especially in a cab huh?
 
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