Want some blue light - 250watt MH retrofit or supplementary CFL?

[Imhotep]

Hi everyone!

I have a small (1.3m x .6M x .4M) autoflowering grow closet with a 250 watt HPS. I get good yields off this setup, but my plants sometimes look pretty sick and tend to get really lanky. I have to keep raising the light to avoid bud burn, which means that only the very top of the plants are getting the best light.

I briefly considered replacing my HPS bulb with Ceramic metal halide, but have decided against it due to their scarcity in the UK and high price.

Now I'm left thinking one of two things:

1. Get a 125watt maxibright 6500K CFL + lead (£30). I thought I could use it exclusively for the first few weeks of veg and then switch on the HPS and keep the CFL as a supplemental side light. This would pretty much even out the cost of the extra electricity and add blue through throughout the entire grow instead of just veg.

2. Get a Powerplant 250watt Metal Halide retrofit bulb (£15) and run it for the first 3 weeks before swapping it out for the HPS when flowering begins. There would be no difference in electricity use as I could only have one bulb on at a time.

What do people think is the best option?

Obviously, the MH retrofit bulb would be half the price of a CFL and lead, but I've heard retrofits aren't always too great. Also, most of the really bad plant stretch seems to happen in early-mid flowering when the MH wouldn't even be on. Would vegging under MH prevent this, or is it be better to have a less intense blue light running throughout?

Thanks in advance.

 

[Scrogerman]

Hey bro,
yeah your barking up the right tree, Blue light will help reduce stretch, while red end promotes it, learn to LST, Scrog, those tecs will help you controll stretch, even with just HPS.(you can play stretch to your advantage actually )
I use spectrum adjusted/enhanced HPS, like growlux, & train/Scrog my plants, never have a height issue, but theres a bit to learn with it.

Id even go with running MH through first part of plant stretch(wks 2-4 of 12/12) if plant/strain stretch was a major concern, as is with Sati's, haze's etc. even then id be training, pinching, crushing(a type of HST) which also helps halt stretch!

I use CFL's myself, both to start & as suplimental, but theres alot to consider, your prolly better off learning to train & get spectrum adjusted HPS lamps. if you can keep the cab cool combos are fine, so is running MH the way ive sugested!

Still havent run CMH but i do want to, after seeing the spec/results!

G'Luck

 

[Imhotep]

Hi Scrogerman,

Thanks for the advice. There's a lot of interesting stuff you've mentioned.

I've heard about enhanced spectrum bulbs, but read that they add only marginal amounts of blue light. Still, I need to replace my HPS tube soon, so I'll probably try one out.

LST sounds interesting. I'll have to read up on how to do it.

Could you elaborate on CFL considerations a bit? I thought you pretty much just hang them up a couple of inches from the plants? I guess there's increased heat to consider - I can't seem to find any solid details on how much a 125watt CFL would kick out.

MH Retrofit does look tempting, and it's very inexpensive.

Thanks again! I've got plenty to think about.

 

[Scrogerman]

Hey man, LOL!

 

[Scrogerman]

heres a couple of links for ya:

https://www.icmag.com/ic/showthread.php?t=115377

http://www.angelfire.com/cantina/fourtwenty/yor/lightres.htm

btw, for the money the spec/enhanced adjusted HPS lamps are very good IME. Still if i still had my MH/Super MH units i would run them tbh. (veg through to most of stretch, say end wk3 of 12/12 then wack in HPS).


G'Luck!

 

[Scrogerman]

I see your problem, 250w HPs has a 2x2ft approx light footprint, your cab is 1.3m long, so you want to supp with CfL, yeah that'll work fine, but not as good as 2 AC'd HPS lamps. Either way you'll win!

250w kicks ass in little cabs with the right footprint: That canopy hit 1.3-1.4gpw(grams per watt)

 

[Imhotep]

Hi Scrogerman.

Sorry, I don't have a camera, but it's 1.3M High, .6M wide and .4M Deep. Here's a picture I (attempted) to draw in paint.

Sorry, I put my dimensions in the wrong order - As you can see, my grow space is pretty tall (although the plants still manage to stretch almost to the entire height.. grrr..), but I don't have much width or depth to play with. It's only slightly wider and deeper than my 250 watt HPS reflector. I also have a 6" fan and a 120mm extractor. I don't have exact temps but it seems warm, but not too hot in there.

The annoying thing is, the plants get good light and I can keep the HPS quite close, but once the stretch starts I get one or two main stems on each plant shooting straight up, forcing me to move my HPS further and further up, away from the main body of the plants.

I've also been reading about LST and that sounds like it might be an answer, although I'm a bit limited in how much I can spread 'em out. Thanks for those links, I've just looked at them and they look very useful - bookmarked!

 

[Scrogerman]

always measure LxWxH, always bro(lenght x width x height), its confusing otherwise & my posts are wasted energy, you wont need supplimental CFL in that shape at all. Just use the 250, spectrum adjusted lamps & your stellar. or get MH for veg & stretch like ya said before.

2ft x 1.333ft = 2.6ft2, if my crap math serves your over 90wpsf there, which is plenty more than enough(i think my math is right there?) 250w's / your square area(2.6ft2) = 96wpsf, fkin loads, you need nothing else but either MH for veg & stretch reduction-maybe. Instead you can train, lst. timing will be the important bit with such a tent. Id just wack in a growlux or sunmaster & your away!

theres some threads about that disscuss blocking farRed light to reduce stretch using FR Light filters, if my memory serves, ill check that out for ya, might be worth a read if it aint over your head. its interesting anyway, but me i just train, its simple tec & very effective.

I would/could pull 10oz's outta that tent with a 250w HPS & a bit of training, not a botha, what more do ya need!


G'Luck bro!

 

[Imhotep]

Hi Scrogerman!

Thanks for the great advice. Sorry again for getting the dimensions wrong, didn't mean to waste yer time.

I'll either get an adjusted spectrum lampr or an MH and I'll definitely start LSTing on my next grow. Cheers!

 

[Scrogerman]

No worries, im just as much at fault for expecting you to know how we write up dimensions on this/these sites lol!

one of these or ive seen growlux 250 for £9: http://cgi.ebay.co.uk/250W-DUEL-SPECTRUM-SUNMASTER-BULB-HPS-HYDROPONIC-/370430760357?_trksid=p4340.m263&_trkparms=algo%3DDLSL%252BSIC%26its%3DI%26itu%3DUCI%252BIA%252BUA%252BFICS%252BUFI%252BDDSIC%26otn%3D8%26pmod%3D320674085663%252B320674085663%26po%3D%26ps%3D63%26clkid%3D245297877032063535

You could get a MH lamp too, nothing to stop ya there, but you dont really need em anymore imo, these are good enough

Oh yeah ill just add, that the plants grown in the above pics was with a super son-t plus lamp(HPS) iirc, see it did not matter about heavy blue or red end of the light spectrum because the plants were trained properly.

G'Luck man!

 

[Scrogerman]

Sorry, I put my dimensions in the wrong order - As you can see, my grow space is pretty tall (although the plants still manage to stretch almost to the entire height.. grrr..), but I don't have much width or depth to play with. It's only slightly wider and deeper than my 250 watt HPS reflector. I also have a 6" fan and a 120mm extractor. I don't have exact temps but it seems warm, but not too hot in there.

The annoying thing is, the plants get good light and I can keep the HPS quite close, but once the stretch starts I get one or two main stems on each plant shooting straight up, forcing me to move my HPS further and further up, away from the main body of the plants.

I've also been reading about LST and that sounds like it might be an answer, although I'm a bit limited in how much I can spread 'em out. Thanks for those links, I've just looked at them and they look very useful - bookmarked!

get a little hygrometer bro, you need one & they dont cost much, they measure temp & RH,.. then consider buying a cooltube, well i would! or AC hood of your choice.

5" Exhaust, is overkill but sounds like you'll need a bit of overkill. maybe consider a fanspeed controller too!(AC hood will fix you up)

Yeah, on the stretch, thats how it goes(strain dependant). there are several tecniques to stop or help plants reduce stretch(light spec being one), the stem pinch/Crush tecnique would help you here(HST), dont bother with DM Bushmaster or similar products with paclobutrizol(sp?) that stop stretch, theres easier/safer ways to help halt stretch, Training & Timing being the best way!

Training & timing are all you need to master really! moving lamps up is pretty standard too, & is the norm. learn to train & get you timing(switch to 12/12) right & you need to change nothing, not even your lamp! best thing ive said to you here bro ! still go with the sunmaster/growlux though i would!

 

[Imhotep]

Cool - I'll pick up a dual spec when my HPS is ready to be replaced. Will also get myself a hygrometer, as the local growshop sells a decent looking one for a tenner.

On my last couple of grows, I've pulled about 5 and a half ounces total off two plants. I've always been well happy with that, but I just worked out my current GPW (I'm assuming the calculation is simply grams divided by wattage of lights) gives me a GPW of 0.62.

Even with such a small space, my setup is clearly far from optimal. If LST and a dual speccy light can help me get to .8 or more GPW then it'll all be worth it! And without needing to buy expensive stuff like CFLS.


Thanks again for all the help, Scrogerman! I'll let you know how my next grow goes. If I could +rep you, I would.

 

[Imhotep]

Ack! Got myself a hygrometer and it's reading about 31 degree C after a couple of hours of the cupboard being shut.

Looks like the first thing I'll need to buy is a more powerful fan!

Currently I'm using a 120mm 47 CFM extractor fan. Think I'll probably increase that to a 200mm, 80+ CFM fan to try and get temps down to a stable sub-30 degrees.

I was planning on building a simple carbon filter, but that will reduce my current CFM even more, so I'll definitely have to upgrade my ventilation system first.

 

[Scrogerman]

Id get a Aircooled Hood in that case, like a cool tube, that will get ya temps to where you need them, surly make it easier for you to manage temps & get ya light closer to ya plants. OK it'll need its own dedicated exhaust fan but better than trying to add a 200mm, thats unessasary for you. Theres plenty of grows about on IC with similar working space/area as you, id check out what people are doing for ideas, that'll help. I can pick up a small cooltube for £30-35, not too bad.

G'Luck man!

 

[Imhotep]

Hiya,

Thanks again for the advice. I had a look at some aircooled reflectors and noticed they plug in to the ballast, but my ballast and reflector seem to be wired directly into one another - no plug.

Also, my hygrometer's reporting that the room my grow cab is in can get up to 28-29 degrees when the HPS is on. I'm trying to cool a hot place with only marginally cooler air, not ideal... I'm also getting huge drops in temperature at night, down to just 13 degrees in the cab last night.

I was mulling this over when the obvious solution struck me - on my next grow I'll just flip the light cycle. I'm growing AFs, so it's 18/6. I usually have the lights on between 6am and 12pm, so I'll just swap to 5pm - 11am.

This way my lights will be keeping the girls warm during the cold, cold night and not frying them during hottest part of the day.

I'll see how this effects temps and go from there.