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How to set up a basic closet grow space

Printed From: Sensi Seeds Shop
Category: Sensi Seeds
Forum Name: Indoor Growing
Forum Discription: Questions and answers about indoor cultivation
Printed Date: 17 November 2019 at 05:25

Topic: How to set up a basic closet grow space
Posted By: farmer mick
Subject: How to set up a basic closet grow space
Date Posted: 15 November 2006 at 18:19

I’m writing this specifically for new gardeners interested in growing weed in small spaces for their own personal use. Firstly, I’d like to say that the following is based entirely on my own experience and other growers may have further information or tips to add. I hope someone, somewhere finds it helpful.

This system is designed for use with one 250w High Pressure Sodium light, which uses relatively little electricity and generates relatively little heat. It is a very simple system that does not require a lot of equipment, but which works very well if done properly.

This guide is also very basic and deals mainly with setting up a grow space, so it does not go into detail about growing plants, watering, nutrients, pests, diseases, hydroponics, soil, harvesting, drying, etc. You can find that information elsewhere on the forums.

Happy growing...

1. If building your own space, try to locate it in a dark place that does not get very hot or very cold. It’s probably easiest to do this in the attic or basement.

2. Start by building a frame from 2inch x 3inch beams, then nail plywood or heavy cardboard all around it, with a door on one side to allow access. Make it around 3ft x 3ft in size, with a height of up to 6ft or 7ft, depending on the available space.

3. You will need to make the space as airtight as possible, with no gaps anywhere that allow outside light to leak in.

4. If you’re converting a closet, the basic structure is already there, so just do whatever you can to cut out any light leakage.

5. Line the inside of the space with reflective material like mylar, white plastic or titanium white paint (flat not glossy).

Setting up the light:

1. Fix two hooks at the top of the space on either side of the room and hang a long chain between them. You can hang the grow light from this chain, and use the links in the chain to raise the light upwards and downwards depending on the size of the plants.

2. It’s better to put the ballast (the box that regulates the current in the light) outside the grow room. What I’ve done is cut a small section off the bottom corner of the door, just enough to fit the cable running from the light to the ballast. The ballast stays outside the room and the wire runs through this gap so that, when the door is closed, no light is escaping from or entering the grow space.

3. You will also need a good quality timer plug to control when the light switches on and off. These can sometimes have internal fuses that prevent surges of electricity like those produced by high-intensity lights, so you might also need a ‘relay’ to eliminate this problem. You can buy these at most good electrical stores.

4. Different lights are normally recommended for the various stages of a plant’s growth (ie seedling, vegetative growth and flowering). However, in my experience, a 250watt HPS can be used for all stages of a plant’s growth, without any major adverse effects.

Setting up ventilation and climate control:

1. The most important piece of ventilation equipment is an extractor fan. In a room measuring 3ft x 3ft, a 4inch (100mm) bathroom extractor works just fine. Cut a hole the same size as the fan somewhere near the top of the grow space and install the extractor, with ducting (flexible tubing) to carry the air from the grow box to another area (preferably the attic or outdoors).

2. Cut another hole the same size somewhere near the bottom of the grow box to allow fresh air to be pulled in.

3. If light leakage through this hole is a problem, cover it with a dark mesh (you can make your own from black tights) to reduce the leakage as much as possible.

4. An ordinary fan should also be used to move air around the grow space 24 hours a day. This promotes the health of the plants, helps reduce the risk of mould and also strengthens the branches and stems. If possible, hang it on the wall of the grow space, blowing between the light and the tops of your plants.

5. You should also get a thermometer and hang it inside the grow space, around the same height as the tops of the plants. An electrical thermometer that also shows humidity levels is the best.

6. Plants will grow well at between 20 Celsius and 30 Celsius, with 25 or thereabouts being ideal. If the temps are too high, a larger extraction fan should solve the problem. If they are too low, you might need a heater, or else use a timer to turn the extractor on and off at regular intervals, thereby retaining more of the heat from the lamp inside the grow space.

7. Humidity should be between 40% and 50%. If it is too high, a larger extractor fan or a dehumidifier should solve the problem. Low humidity can be solved through putting the extractor on a timer or by installing a humidifier.

8. You will need to experiment to find the best way to keep the temperature and humidity within the correct range, but a I find a 250watt HPS in a room packed with plants tends to keep both within safe limits all on it’s own.

9. If smell is a problem, you can attach a carbon filter to the extractor fan, which is probably the most effective solution. Alternatively, you could put an ozone generator or de-ionizer in the area where the air from the grow box is being extracted to.

Growing plants:

1. A 250w light is most suitable for growing smaller plants. In a 3ft x 3ft space, you can easily grow nine plants ( 3 x 3) to a height of around 2ft or 2.5ft each.

2. Start the plants in small pots at a distance of around 3ft from the light bulb, using the timer to ensure the light stays on for 18 hours every day and switches off for the other six hours.

3. If you’re growing from seeds, wait until the plants have a couple of sets of serrated leaves, then move them to within 2ft of the light. You can do this with cuttings as soon as they have taken root.

4. As soon as the roots fill the small pots, transfer the plants into larger ones, 10litres minimum.
5. Once the plants begin to grow strongly, move them within 1ft of the light, but keep the fan blowing across the tops to make sure they don’t get burned by the heat of the lamp.

6. When the plants reach 9-12 inches in height, use the timer to change the photoperiod to 12 hours light and 12 hours dark every day. This will trigger flowering. You must make sure that there are no light interruptions during the dark period, or else bud-production will be hampered.

7. Within 6-9 weeks, depending on the strain, you should be harvesting several ounces of bud, enough to last you until the next crop is finished!

This is what can be achieved with one 250watt HPS: - -

Posted By: john_squat
Date Posted: 15 November 2006 at 20:46
wicked stuff Farmer Mick!
Thats sure to come in useful for a lot of people!

Posted By: holistic
Date Posted: 16 November 2006 at 00:33
nice 1 m8

Posted By: TheWeeD
Date Posted: 16 November 2006 at 02:12
    Cheer's for that from a newbee grower give good referance gide for us beginers.

Posted By: john_squat
Date Posted: 16 November 2006 at 21:19
"5. When the plants reach 9-12 inches in height"
Is this all? I was under the impression that they had to be bigger than that before commencing flowering cycle. So how much would you expect a plant to grow (height-wise) during flowering?

Posted By: farmer mick
Date Posted: 16 November 2006 at 23:17
They will double or triple in size after the lights are turned back to 12/12, depending on the strain and the phenotype. A lot of Sativa strains will grow even more than this and can be put into flower when very small.
If the pots aren't big enough, it will stunt the growth during flowering and lead to unhealthy plants and poor harvest. I've edited the original post to make it clear that plants should be grown in pots at least 10litres in size.

Posted By: Sticky
Date Posted: 19 November 2006 at 10:27
Always loved your work farmer jim.

Its the fact you go to the trouble to share your knowledge, which i have always thought accurate and current.

Hi everyone goodluck with your cupboards they can produce some great results, due to the light being boxed in and intesified, i once grew a Hog and cut it back to 2 arms it went of and i did it with a 423w  sont t .  so go for it, and good luck.

Sticky so high

Posted By: Nick
Date Posted: 26 November 2006 at 04:59
    Hey Mick,

Finally got all the materials. Well, most of them. And my available space got smaller. It's now only a 26x24 inch area. I have six foot structure members but it looks like a damn coffin! I'm a little concerned it's going to be too top heavy. Allowing 2-3 feet from my HPS light, and say, a foot off the floor for the container. I'd like to grow at least a three footer or more. There's 6 feet! Teather lines don't appear possible. Well maybe. That's all I see. You? Would 5 feet high be too small / close to the plants?? Thanks Dude.

San Diego

Posted By: peter_spliff
Date Posted: 26 November 2006 at 13:24
5 feet would be more than enough cupboard is approx 5 feet and havent come close to running out of space height wise but i have only been growing indicas so far.but even with a raging sative the top cola could be tied down to allow it more growing space.also if budburn were to become a problem u cud get a cool tobe or a heat shield to reduce or deflect the heat frm da bulb.happy growing          pete

Posted By: Nick
Date Posted: 26 November 2006 at 15:35
    I've heard that cool tubes refract the light which is not good. Anyways, I already have a 250w HPS. What's the closest I can safely grow from it?? I thought I heard something like 2-3 feet from the light. Is that the closest? And in a 2x2 foot area I'm very limited to number of plants, but want top yield.

Posted By: farmer mick
Date Posted: 26 November 2006 at 19:03

With a 250w HPS, you can safely grow plants to within one foot of the light, even closer if the ventilation is good in your grow space. I have grown plants to within 8inches of my light without any burning, but only with buds that are to one side of the bulb and not directly below it. Any buds growing directly underneath the bulb are likely to get burned if they get within 10-12inches.

Some tips:
1) Grow the smallest plants directly below the light and keep them at a distance of 12inches. Keep the larger plants to the sides of the grow space.
2) Hang a fan on the wall of the grow space so it blows directly underneath the light and above the tops of the plants. This will dissipate the heat from the bulb, without affecting the intensity of the light.
PS. My grow space measures 30x24 inches, with a height of around 60inches between the light and the floor. I can grow six plants to around 30inches, while keeping the pots on a table around 18inches off the floor.

Posted By: Nick
Date Posted: 28 November 2006 at 17:23
What's the best way to make your box "AirTight"??
I'm not a carpenter, nor have any woodworking skills. I bought my seeds, bought materials to make box, having probs making box too top heavy, no tools, and now have misplaced my F***ing Seeds! This sucks! I need some hits.

Posted By: farmer mick
Date Posted: 28 November 2006 at 18:01
Just make sure everything fits together well, with no gaps. Also make sure that when the door of the grow space is closed, there are no gaps around the edges.
Hardware shops sell strips of plastic stuff for blocking out drafts around doors. This will do the trick, you can cut it to the size you need...

Posted By: streetkarp
Date Posted: 08 December 2006 at 21:25

Hi. First off im a student, so hopefully u can see where im coming from here. Ive become fed up off paying for green and am looking to set up growing my own crop. Im currently considering buying Hindu Kush Seeds. I have plenty of space and live in a loft room, but after having a brief look around for aparatus have discovered its going to cost me a bit to start my own crop. Minus seeds and Space to grow them (like a cuboard) can anyone give me a rough idea on how much it is going to cost me to buy the gear to do this? I'd really appreciate cheap/bargain prices. Its the lights im worried about to be honest after looking around on the internet, its looking about 100 quid for a light.Which is more than double what im willing to spend!And this is going to be a throw away opperation come july.

How much for a light and the ventillation equitment and any other bits and pieces that are needed? im guessing its going to smell quite a bit too, so any ideas?

All help is appreciated. Would be good to see what others have generally spent to start there own crops?

Posted By: john_squat
Date Posted: 09 December 2006 at 14:51
You tried Growell? Their prices are quite good. Though admittedly, the initial 1-off cost to buy the equipment (light, control gear, ventilation, tray & water pump, etc)is fairly high if your buying everything brand new.

[p.s. If smell is a problem, maybe a carbon filter would come in handy?]

I would say its more than a worthwhile investment, but if you plan on ditching it come July then maybe not...

Try if you haven't already.

Posted By: Terence Donovan
Date Posted: 14 December 2006 at 00:50
I'm spending aprox £350 for my first wardrobe grow, I'll be growing 5 plants in soil and this is about as cheap as I could budget it with fans, filter lighting etc

Posted By: streetkarp
Date Posted: 15 December 2006 at 21:37
Quick Question. The help so far has been useful. And ive found two or three great bargains online.

I have one question : I own a blacklite, which i bought last year just for ambient affect. its flourescent and is 20w and 24" long. could i use this? any thoughts?maybe buy a couple of others.they always have other uses if i ever decide to retire from growing. Just ive read on a couple of sites now, that they can be used.


Posted By: shell
Date Posted: 16 December 2006 at 20:37
farmer mick you are genius looking at your pics and reading your advice well after your help big time i am a growing virgin and a bit clueelss read your post  i got a room with a bit shelved off the side with the shelf is 4foot long 3 foot wide 4 fooot high ... the other half the room is 3 1/2 foot long 3 foot wide 8 foot high .. which would be the best 1 to use i got a 250 watt Embarrassedlight like you said and a fan is there anything else i need i got 4 sets of seeds anda book on growing callled closet cultavator i think any advice would 110% appreciated thanks far your time farmer mick shell EmbarrassedEmbarrassednot smoking

Posted By: farmer mick
Date Posted: 17 December 2006 at 12:51
You should use the part of the room that's 8ft high, it gives you more space to work with. Once you set up the light and extractor fan, you should be good to go.
A second fan to move the air around the grow room is a good idea, and an electric weather station to read temperature and humidity would also be worth getting.
After than, it's just a matter of experimenting until you perfect your growing technique.

Posted By: shell
Date Posted: 17 December 2006 at 18:04
thanks farmer mick will take your advice just seen a starter kit on e bay doyou think thiswould be useful .

Posted By: farmer mick
Date Posted: 17 December 2006 at 19:30
I don't know what a contractor is exactly, but you need two fans on top of what's on this list - an extractor fan to remove stale air from the grow room and a normal fan to blow the air around inside the room. Otherwise, you have all the soil, pots and nutrients there to grow five plants..

Posted By: shell
Date Posted: 17 December 2006 at 19:44
thanks again farmer will  bye that then and go with 5 plants to start and after the first crop and i no what i doing i may add 5 more pots  thanks i seen a bathroom extractor fan on there would that be ok it was about 12 quid

Posted By: farmer mick
Date Posted: 18 December 2006 at 00:09

That will work fine, they can be a bit noisy though, if you're a light sleeper and the grow room is near the bedroom...

Posted By: UltraHazzz
Date Posted: 18 December 2006 at 01:00
farmer mick what type of exaust fan do i reconmend
quite pleaseeeeeeeeeeee lol

Posted By: farmer mick
Date Posted: 18 December 2006 at 18:25
One of these guys should be fairly quiet, I'd imagine... I use a bathroom fan myself, you get used to the noise. -

Posted By: Nick
Date Posted: 23 December 2006 at 20:46

Posted By: farmer mick
Date Posted: 27 December 2006 at 20:28

The bathroom fan should be very easy to wire up, there's usually just two individual wires - live and neutral - which are attached inside the fan the same way as you'd wire a plug. Bathroom fans are often connected to the lightswitch, so they are usually designed for 220v-240v electrical systems. This means you can simply attach a plug to the other end of the wire and safely plug it straight into the mains.

Posted By: Nick
Date Posted: 28 December 2006 at 05:50

Posted By: shell
Date Posted: 01 January 2007 at 18:22
hey guys still new but hopefully got through the first stage but need some reassurance on next step well here goes... have just potted seeds in small pots due to their germination between kitchen paper but what now every where i read its different so am still putting them in airing cupboard in darkness but dont know when to feed  so please help am doing so well

Posted By: Nick
Date Posted: 02 January 2007 at 05:17
    Hey Buddy,
Here's how I just germed 4 out of 4 White Rhino seeds:
Doubled or tripled paper towels top & bottom. Placed them into a square Tupperware, about 3 or 4 x 5 inches. Under the faucet, I dripped water over all of it getting it very damp all the way through, but not so that water is running around the bottom of the container. Pull back the top layers of paper towels and place seeds on the bottom layers. Lightly place top layers on top of seeds and, lightly, press towels around seeds, moulding around seeds. Seal lid, burp, and place on a heating pad set to low. This will aid in maintaining constant temperature of around 72-78 degrees. I did this and two of my Rhinos germed overnight.! By the end of the next day I had all four seeds germed. That was about a week ago and today, under constant 250HPS light, they stand about 3-4 inches high and very healthy. 3rd set of leaves sprouting as I speak. Hope this helps. Do what you want with it.
Good Luck and Happy Toking!


Posted By: farmer mick
Date Posted: 03 January 2007 at 17:04
Nice work Nick. Here's to a bumper harvest!!
Shell, put the pots under light as soon as the stalk breaks the surface of the soil.

Posted By: shell
Date Posted: 04 January 2007 at 15:45
farmer mick  did that with 2 of them and they growing fine i think but another 2 are just peeking out of soil and other 3 well i carefully found them in soil but no grow do  u think i planted them too deep and wot can i do to save them thanks shell

Posted By: farmer mick
Date Posted: 04 January 2007 at 17:38

The germination failure could be down to a number of things.

Did you soak the seeds in water overnight before germination.? Did you germinate them in paper towels before putting them in the soil? Did you make sure the soil is moist, but not waterlogged? Is the temperature in the right range, 25-30 degrees?
The depth of the seed shouldn't prevent it from germinating, but the ideal depth is around one inch or so.

Posted By: Asphyx1us
Date Posted: 07 January 2007 at 18:29

I've been browsing through this forum for the past 2 or 3 days so I'm still a noobie. Although I read a lot and this guide seems to be awesome! :)
I've never ever grown plants before, so it will be hard (I think), but I'm highly interested in growing.
Currently I'm investigating the (dis)advantages, the prices of fans and all that kinda stuff you need to buy.
But I got a greenhouse in the backyard, so does this guide also applies to that? Because you have lots of sunlight coming in...
Btw. It's not a 'heated' greenhouse, or how do you call that, I meant to say that it's just a wooden shed with glass windows everywhere without a source that heats it.
There's maybe also an option to keep the plants in the attic. Not sure yet.
If I start growing, I will post my progress or something, don't know yet?


Posted By: farmer mick
Date Posted: 07 January 2007 at 19:09
The greenhouse will work fine as long as there isn't any light pollution getting in from the street or from nearby houses during the night-time. Plant seeds or clones at end March/ beginning April and they should be ready for harvest by end October. According to weather forecasts, Europe can look forward to a warm 2007, so heat shouldn't be a problem.

Posted By: Asphyx1us
Date Posted: 07 January 2007 at 19:14
Thanks a lot !

Posted By: cruzsurfer
Date Posted: 13 January 2007 at 16:09
Thanks a bunch, this is very helpfull.....

is it better to just grow them in dirt or should I try and do some kind of hydroponics?  

any help would be apreciated so high

Posted By: farmer mick
Date Posted: 13 January 2007 at 18:52 -

Posted By: -idd
Date Posted: 17 January 2007 at 17:04
Farmer Mick,
    Based on your experience, what strain do you feel is most appropriate to this setup?  Because you have 30-50cm of headspace below the light, and the plants are less than a meter high at harvest, it seems that a stockier variety would most suit your setup.  Do you pick a plant based on growth characteristics or smoking quality?

    If you had a sativa strain, would training within the 1m vertical 'light window' allow for as dense growth as a more powerful light, or would you recommend a bushier plant from the start?

    Could you recommend a handful of strains specific to the equipment you use? please include suggestions for adapting leggier strains to this setup.

Posted By: cruzsurfer
Date Posted: 21 January 2007 at 17:09">">

    I bought the cabinet at a local hardware store for 108.00 ,  bathroom extractor for 14.00 , fan 20.00  250 watt grow lux bulb which I had for a while now, had it in my closet but a horible set up..  this is US dollar so I'm sure most of you guys can get it cheaper..     I know this is going to work killer...    Thanks Mick....  

Posted By: kalani
Date Posted: 27 February 2007 at 21:58
I come from tahiti (french) and i never start a indoor grow.
U say "
a 250w light is most suitable for growing smaller plants. In a 3ft x 3ft space, you can easily grow nine plants ( 3 x 3) to a height of around 2ft or 2.5ft each."

Where i can find seeds
that obtain a height of around 2ft or 2.5ft ?
What is the variety of those seeds ?

I always grow outdoor in tahiti (weather is like hawaii). But i' like to grow indoor because the plants outdoor is to big (height about 5-6 feet).
I'm a beginner in a indoor grow.


Posted By: farmer mick
Date Posted: 27 February 2007 at 22:59

Hi Kalani,

When growing indoors, you can control the height of the plants by putting them into flower whenever you choose rather than relying on nature. If you grow Indica-dominant plants, grow them under 18 hours light and six hours dark until they're 10-12 inches tall, then change the light-cycle to 12 hours light and 12 hours dark. The plants will finish flowering at 2ft or 2.5ft.

"A rat race is for rats. We're not rats. We're human beings." - Jimmy Reid, RIP

Posted By: Frank
Date Posted: 05 March 2007 at 00:52
Great stuff mick, got me quite interested, real nice of you for taking the time mate....


Posted By: hermes
Date Posted: 27 May 2007 at 04:30
   Hey Mick
I´m about starting my first closet grow (anf firts grow ever) and got few questions. If you can give me a hand here it´ll be very apreciated.
-The closet is 6,3 x 4,11 x 1,9 fts. (H x W x D)
-I´ve got the White Label´s W. Widow and the Sensi´s Super Skunk.
I´m not familiarized with the plants´s size but I think I´ll be able to grow only 3 plants at a time with this space disposition. What is your opinion?
I´m thinking about a 400W HPS, Do you think this is too much? Would work fine with a 250W?
By the way, I´m in Buenos Aires, Argentina. What we smoke here is part of the production that´s made up north (more tropical areas of the country and even another countries too) for international trafic. This is 100% wild rised weed, with almost no human care. The only thing they do, I guess, is show up when is time and take whatever is there. So, the 95% of the weed around are polinized female and probably even some males. Still, you get to smoke some good weed but you always got some seeds on it. Before start with the Widow and the Skunk I´ll try with this guys untill have a beat of experience. Hopefully they are healthy enough to grow. If I get something from then I´ll post few pics to see if you or anyone there has an idea of what they are.
Thanks for you reading time.

Posted By: holistic
Date Posted: 27 May 2007 at 07:10
hi - hermes a 250w hps is fine for that space and welcome to sensi

Check out - Sensi Indoor Mix in Holistic's photo gallery!

Better to live one day on your feet than spend a lifetime on your knees.

Posted By: hermes
Date Posted: 28 May 2007 at 05:06
Thanks for your answer and welcoming Holistic.
One More question: most likely I´ll be able to give to the plants a couple to few hours of sun light by siting them next to a window, still indoor.
Is this a good idea or should I keep them always ander artificial light?

Posted By: farmer mick
Date Posted: 28 May 2007 at 17:01
Keep them under artificial light all the time, moving them around into different environments will only harm them.

"A rat race is for rats. We're not rats. We're human beings." - Jimmy Reid, RIP

Posted By: hermes
Date Posted: 28 May 2007 at 17:06

Posted By: deadin
Date Posted: 06 June 2007 at 18:10
   Nice one dude, will try this myself.

Again well done.

A high is life

Posted By: hermes
Date Posted: 18 July 2007 at 19:21
Hello. I need quick help!
finally Ì`ve got the local seeds germinated, they were growing allright. But a friend told me he had a great plant from a local seed and he couldn`t put it into flower. So i thought if that happen to me I will never know if I done something wrong or it was just the seed, so I decided germinate 3 Sensi`s Super Skunk.
They sprout very well and were growing next to the local ones.
Few day ago i went back home by nightand I found, locals and sensi`s, like they were melted. I didnt know what had happend. Next morning, after think a while, I realized that the only mistake that I could have was the watering. So I water them.  The locals ones came back to life,  in a matter of minutes they were loocking awesome again. But the sensi`s never got better but they didnt die... yet at list. I don`t know the reason. They seem to be fighting but I cant figure what is the problem. May be they were too youg to suport the misswatering? don`t think so, they should be dead by know but they still breading. I`ll try to put on a couple of pics of them to see if someone has an idea about it.

Posted By: hermes
Date Posted: 18 July 2007 at 19:31

I cant upload the pics. I`ll try later


Posted By: Fuzzy Dunlop
Date Posted: 18 July 2007 at 19:41
This is just a perfect way to do it..
Will be helpful for many growers...weed leaf

I grow for my own and loves it like I love to live GOOD !!

Posted By: hermes
Date Posted: 19 July 2007 at 02:04

Posted By: hermes
Date Posted: 19 July 2007 at 02:15

Posted By: hermes
Date Posted: 19 July 2007 at 02:28


GANJA  -  they died because they were not watered.


Posted By: farmer mick
Date Posted: 19 July 2007 at 18:39
No idea what caused your little tragedy, but put the healthy ones in bigger pots asap.

Posted By: Solidopc
Date Posted: 19 July 2007 at 19:14
Woah, maybe those small cups have something to do with it. Bang em in bigger pots like Farmer Mick says. I had one plant that went exactly like that, except it was allmost illuminious green, but it had gone liike that because i had damaged the stem.

Green-Thumb Growing

Posted By: hermes
Date Posted: 20 July 2007 at 05:52


Posted By: hermes
Date Posted: 20 July 2007 at 05:58

Posted By: Ganja
Date Posted: 20 July 2007 at 11:36
It's quite normal that the seedlings didn't come back when the bigger plants did.

The bigger ones hold a lot more moisture within their tissues and can survive not being watered.

The seedlings are tiny, and have no extra capacity for holding water. So, if you don't water them, they'll die.

This goes for every type of damage - bigger plants have a good chance of surviving, because they have reserves of energy food, water and foliage.

Seedlings don't.

Their entire mass - hair-thin stem, two sets of leaves and small root system - probably weighs only a few grams. That means they can hold a few millilitres of water.

------------- - Auto-flowering - Cannabis Seeds!
No growing questions by PM, please!

Posted By: gizerakos
Date Posted: 05 October 2007 at 21:14

1)why 18h not 24h lighting at he veg period?

2)how will a 400w hps cost monthly at the electricity bill?
3)can a plant sustain 2 days without watering?

Posted By: farmer mick
Date Posted: 06 October 2007 at 15:05
1. 18 hours is a more efficient use of electricity.
2. It depends on the cost of a unit (Kw/h) of electricity in the Netherlands. A 400w light uses 7.2 units of electricity every day in the 18/6 light-period and 4.8 units per day in the 12/12 light period.
3. Yes, but it depends on the size of the pot. I grow my plants in either 8litre or 12litre pots. The plants in the 8litre pots need watering every 3 days and in the 12litre pots every 4-5 days.

Posted By: blackmore
Date Posted: 10 November 2007 at 09:59
is there a noticeable and worthwhile difference between the veg of a 24/0hr  vs an 18/6hr schedule?

Posted By: Jonney
Date Posted: 29 November 2007 at 01:13

the size of your electricity bill.

as farmer mick said....18/6 is a more efficient use of electricity.

"It is possible that a certain amount of brain damage is of therapeutic value."

Dr Paul Hoch

Posted By: Nemo
Date Posted: 02 December 2007 at 21:37
Hi, just wanted to say a big thanks to Farmer Mick for this guide, having (largely!) followed your advice I am up and running with my first grow (pictures -  here). You obviously spend a lot of time and energy replying to the numerous questions in this forum, and it is greatly appreciated.So, massive thanks and all respect to you Sir, you are truely and a gentleman and a scholar!

Posted By: blackmore
Date Posted: 04 December 2007 at 15:59
Originally posted by Jonney


the size of your electricity bill.

as farmer mick said....18/6 is a more efficient use of electricity.

lets say electricity isnt a problem.

im thinking logically plants under 24/0 would be larger and more productive than 18/6.
what im unsure about is whether the 6hrs of night has a beneficial/worthwhile effect?

what say you?

Posted By: sarah louise
Date Posted: 07 December 2007 at 00:35
Originally posted by blackmore

lets say electricity isnt a problem.

im thinking logically plants under 24/0 would be larger and more productive than 18/6.
what im unsure about is whether the 6hrs of night has a beneficial/worthwhile effect?

what say you?

I'd say the flaw in your hypothesis is that you are assuming that the plant does nothing during darkness.

There are benefits to dark periods during veg growth. I may not be an indoor grower, but I do understand the basic biochemical processes involved.

Put as simply as possible~

During light periods the plant is collecting and storing and using energy products of photosynthesis for growth. (plants multi task during light periods)

During dark periods, the plant only has to concentrate on using energy products for growth. This energy is supplied via the 'dark reactions'  from energy stored during the light period. As  long as these stores aren't exhausted before the next light period begins, growth during darkness exceeds that which the plant achieves during light periods.

As these are commonly called 'dark reactions' many people believe that darkness is a prerequiste. This is untrue. They are better called 'light independent reactions' because they don't actually need access to light, only access to the products of light based photosynthesis to produce energy in a form usable by the plant.

Hope that makes sense.

Hypothetically, to capitalise on the different aspects of photosynthesis I would ~

Start seedlings under 24 hr lighting as they have little capacity to store energy for growth during dark periods and move them to 18/6 once they had grown on enough to be able to store enough energy that growth was not retarded, but enhanced by a dark period.

Maybe someone who grows indoors and has background in the biochemistry will come along and show me where the holes are in my hypothesis. joint

Posted By: Yaelandar
Date Posted: 20 February 2008 at 11:06
Hi Farmer Mick

Thank's for this really interesting topic.

Yaelandar's Set Up

As your topic is talking about set-up with a 250W i want to show you my cab.

The cab is a 60 cm large 40cm long with an height of 1.80m. The lamp is a 250W HPS. There is a RVK 125mm and also some fans and holes at the bottom of the cab for air circulation.

To highlight my comments please find a picture of the set up :

If my reply does matter you please tell me and i will remove it.

Peace Yael

------------- - Yaelandar's Growroom Northern Lights Day 81 (52 days of flowering)

Posted By: Boneprone
Date Posted: 27 February 2008 at 15:34
awesome dude. I want to get something like that geared up.

Posted By: Rendered
Date Posted: 28 April 2008 at 10:23
I did not read the whole post so sorry if this is already mentioned.

If you use a passive intake it should be slightly larger than the fan (125mm fan = about 150mm intake) sumthin like that, the important thing is that its slightly larger.
This will create a small underpressure in the room and fan will have an easier job extracting.

Posted By: cardante
Date Posted: 25 September 2008 at 17:15
Hi guys...

If I have 1.2m x 1.2m x 2m, 600W, cooltube and 125 out-fan do I need in-fan and which one?My homebox also has air holes at the bottom (on 3 sides) but they will leak light if opened...

don't want to cross-post so here's the thread

Posted By: jay jay
Date Posted: 09 February 2009 at 22:32
%3co%20high%3co%20high%3co%20high%3co%20high%3coint%3ceed%20leaf nice one mate 250 hps are £70 at growell with control gear and work  verry verry well good luck lads the jay jay fella

j allen

Posted By: jay jay
Date Posted: 09 February 2009 at 22:42
can some one tell me whots up with my plants by mid day my plants look like they are drooping   but are ok the next morning i water every day with food is it to much eney hellp plz dont whont them dyeing on me%3cry

j allen

Posted By: highline
Date Posted: 31 March 2009 at 19:12
class grow guide btw, very fukin usefull!!!
does anybody kno of a grower / helper to help me get a set up going? anybody kno 1 in edinburgh, scotland? my cupboard is 2ft x 4ft and bout 7ft tall. is that big enuf? how much will my first expense be to get set up with just a couple of plants?
toke on

never go a day without a J :D

Posted By: youngweedster
Date Posted: 16 April 2009 at 08:02
Really great guide, even for a beginner like me, it was eas yto understand and I hope I can implement it into my next grow%3ceed%20leaf

Posted By: Cabbage Patch Kid
Date Posted: 05 May 2009 at 18:17
very helpful guide, cheers. you dont see many grow room guides about.
I built my own growspace from scratch - near on all of it was from the same shop, including the extracion fan and carbon filters.
it took me the best part of 2 weeks to build and cost a little over £200 and occupies half of my garden shed.  kudos to B&Q!!
just a heads up on those carbon fiters designed for kitchens. they dont work for weed that well. %3c3c3clown  
they did work but didnt mask the smell completely and when they get moist stop working altogether. for £10 a pop i though it was worth trying them out.
 using those £15 bathrom extraction fans did work well for me but getting two would a good idea if the room is over say 1.5m³, intake and exhaust.
just my 2p. %3clunt

Thus saith the Lord, As the new wine is found in the cluster, Destroy it not; for a blessing is in it....   im actually completly atheist but its nice to know jesus approves

Posted By: ricky_sensi
Date Posted: 09 July 2009 at 00:13
Super handy guide, thanks for the information and for taking the time to put it all together %3ceed%20leaf%3ceed%20leaf

Posted By: samstranky
Date Posted: 11 August 2009 at 20:00

Posted By: Casbud
Date Posted: 29 August 2009 at 06:17
Hey guys,

I have been researching growing for some time and I think I'm ready to go as far as methodically. I have read a lot about actual growing methods and what not. Im going to be growing in my closet...hopefully. But I have some main concerns.

The first concern is getting the stale air out and fresh air in. I cant cut any holes in the door. I was thinking of installing a water closet style overhead fan, simple and seems like a good idea.

The second concern is the smell. I have no ideas other than oder eliminating type stuff that doesn't effect the plants.

The last point is not really a concern but more of a thought I plan on suspending the grow light on a chain. Is this the best method to have a heigh changing grow light?

Thanks for all the help and OP (mick i think) you rock your really helping me get my garden started!!


Posted By: DriveBy
Date Posted: 29 August 2009 at 08:24
My closets air in is easy cause theres huge draft under the door that blows canddle out plus oscillatin fan startin every 2 hours near floor suckin fresh air under the door and opposite wall upper left is out vent. Got 250W HPS and tempature is 25c at winters and 28c at summers. Can fit eight i.e norths but now three BJs and JH comin gooooooood %3cool

Posted By: yoka86
Date Posted: 15 September 2009 at 19:56
Do you think places with 26 and 27 hottest temperature without lamps turned on are good to grow ?

Posted By: naash
Date Posted: 25 September 2009 at 15:42
hi there, the first time am growing, would like to know if i can use only 2502 hps start to finish? from only seed, sprout, veg, flowering please little tips.... thanx

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