Lighting System for Seedlings

Hello all, thanks for clicking,

so i am in the midst of beginning my first crop and wanted to share my lighting plan in hopes some of you could assist me with some feedback and advise.

I currently have one 300w CFL , and I plan to purchase another before I start, which I was going to give the seedlings up until the vegetation stage where I'll be adding a MH or HPS [still undecided]. Do you think 2 x 300w CFL's would be a little over powering for the baby seedlings or the contrary? Also, at what distance above the seedlings would be recommend? I am also unsure of how many plants I am going to have although I estimate around 5

Once I am into the vegetation stage, what would you recommend for the vegetation and flowering? I know its advised MH for veg and HPS for flowering but I am working within a budget, so would ideally like to use the same light throughout veg and flowering, with also the CFLs on each side of the grow. I have heard 600w can also be a little too hot for the tent, so would 2 x 400w MH or HPS make a sufficient difference?

Thanks again in advance for the advise.

You could start with one of the CFL's when they are seedlings and as they get bigger throw in the other 300w cfl. It probably wouldn't overpower them to use both at first but it's also probably not needed.

How big is your tent? I run a 600w in a 4x4 and it get's pretty hot, but I have an aircooled hood to keep it cool cause I also run a 400w in same tent for side lighting.

you can get a switchable ballast with both HPS and MH bulbs for about $150.00 all day long on e-bay. For seedlings I have 2 150w cfls one for each of the 2 gurlz I grow per cycle. I keep them about 2" above the plants. I go into veg under 400w after about a week.

robbzilla said:

You could start with one of the CFL's when they are seedlings and as they get bigger throw in the other 300w cfl. It probably wouldn't overpower them to use both at first but it's also probably not needed.

How big is your tent? I run a 600w in a 4x4 and it get's pretty hot, but I have an aircooled hood to keep it cool cause I also run a 400w in same tent for side lighting.

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Agreed ...tent size would be good info...And, I also use a cooltube with booster fan. my tent is 20" x 36" x 60"

robbzilla said:

You could start with one of the CFL's when they are seedlings and as they get bigger throw in the other 300w cfl. It probably wouldn't overpower them to use both at first but it's also probably not needed.

How big is your tent? I run a 600w in a 4x4 and it get's pretty hot, but I have an aircooled hood to keep it cool cause I also run a 400w in same tent for side lighting.

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Thanks for your reply,

My tent dimensions are 120x60x180 [cm]. Does the air cooled hood make a huge difference? And do you think you would see a substantial difference in yield between 600w & 400w. Thanks again

To directly answer your question though, yes, an aircooled hood makes a big difference with a 600w, not so much with a 400w though unless you're in a small space. 400w's are pretty cool though

I do my seedlings under a 15 watt T8

300 watts is a lot for seedlings

robbzilla said:

Wait a minute, maybe I'm not converting right, are you saying your space is 10x5x15 (feet)? If so that is huge and a 600w, or a 400w, wouldn't cover that space. A 600w can facilitate roughly a 4x4 space, and a 400w does a 3x3 space, so neither of those individually is going to give you a good end product. An easy way to figure out how much lighting you want is to calculate what it would take to get 50w's per square foot. With a space that big I'd either section it off, to make something a little smaller, or start looking at doing a much larger set up for your grow.

To directly answer your question though, yes, an aircooled hood makes a big difference with a 600w, not so much with a 400w though unless you're in a small space. Either way, your space is huge so unless you want to parcel out an area that's smaller you're going to have to look in to a bigger grow set up.

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120x60x180 centimetres, sorry for the confusion. It's quite an intimate space. So would you recommend getting a cooler for a space this size?

sunchild_sc said:

120x60x180 centimetres, sorry for the confusion. It's quite an intimate space. So would you recommend getting a cooler for a space this size?

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Yea my bad dude, I was way off with converting. Yea so for that space a 600w would be overkill, even a 400w is kind of big for the space but if you got a hood you might get away with it. How many plants are you looking at growing? Are they for personal use? What's your budget like for lighting? There may be better options for you space than HID lighting depending on the answers to those questions

I use a 400w mh as a min. Why because I like to waste power hahaha

Easiest way to get an idea what will work veg / seedlings use 2000 lumens per square foot.
Flowering needs 2250 - 2500 lumens per square foot.
Example 4feet X 1.5feet X 2000 lm/sqft = 12,000 lumens
Caution - small spaces can be hard to control as temperatures can change quickly - frying plants.

Too much light can make buds less flavourful by suppressing turpenne production.

robbzilla said:

Yea my bad dude, I was way off with converting. Yea so for that space a 600w would be overkill, even a 400w is kind of big for the space but if you got a hood you might get away with it. How many plants are you looking at growing? Are they for personal use? What's your budget like for lighting? There may be better options for you space than HID lighting depending on the answers to those questions

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Thanks for replying, Im looking to grow 5 upwards if my space allows it, and for monetary purposes mainly. I am on a budget but don't mind spending a little more if it will aid me and I have the right information, as I am still a newbie above all. I was also looking at grabbing an air cooled reflector and filter too this week.

Considering the space would you suggest one 400w? I was thinking as length ways is 120cm I could at least fit two side by side, and if I only use one 400w because of heat purposes, will this be enough to reach 5+ plants?

Thanks for all the info robzilla!

sunchild_sc said:

Thanks for replying, Im looking to grow 5 upwards if my space allows it, and for monetary purposes mainly. I am on a budget but don't mind spending a little more if it will aid me and I have the right information, as I am still a newbie above all. I was also looking at grabbing an air cooled reflector and filter too this week.

Considering the space would you suggest one 400w? I was thinking as length ways is 120cm I could at least fit two side by side, and if I only use one 400w because of heat purposes, will this be enough to reach 5+ plants?

Thanks for all the info robzilla!

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Yea I wouldn't recommend anything bigger than a 400w in the space you have. It should handle 5 small to medium plants fine. You could also look in to LED lighting though if you have the budget. Usually easier in a smaller space since they'll generally run cooler than HID lighting. If you're set on HID lighting though, which is fine, then you'll more than likely want a hood/exhaust set up to keep temps in line

check out a 315watt LEC (light emitting ceramic). will outperform a 400hps easy and runs very cool too compared to hps/mh. works great for veg and bloom.

My buddie has a small 2 ft wide by 3-4 ft long by 3 ft high tent n he has 3 med size plants in it with 2 of the 300 watt CFLs n his plants are short n bushy a 400 watt hps would work awesome in a smaller space but the do put off heat so a air cooled tube might work better well good luck

robbzilla said:

Yea I wouldn't recommend anything bigger than a 400w in the space you have. It should handle 5 small to medium plants fine. You could also look in to LED lighting though if you have the budget. Usually easier in a smaller space since they'll generally run cooler than HID lighting. If you're set on HID lighting though, which is fine, then you'll more than likely want a hood/exhaust set up to keep temps in line

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Okay, my mind is telling me to get one 400w HID. Would I need to change the light spectrums for each stage with an LED or would it cover the whole grow? Thanks again bro

rkymtnman said:

check out a 315watt LEC (light emitting ceramic). will outperform a 400hps easy and runs very cool too compared to hps/mh. works great for veg and bloom.

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Thanks for replying. I haven't heard of LEC lights, do you think you could link me to a/some product/s

LED would cover the whole grow but if you're thinking about going with HID I say go for it. I've grown with HID for years and love it. You could look in to the LEC bulbs too, like someone mentioned above, they do run a lot cooler

sunchild_sc said:

Thanks for replying. I haven't heard of LEC lights, do you think you could link me to a/some product/s

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you can buy a kit less reflector for around $200. or a fully assembled for about $400.

here's one source: http://growershouse.com/sun-system-lec-315-light-emitting-ceramic-mh-fixture-240v

robbzilla said:

LED would cover the whole grow but if you're thinking about going with HID I say go for it. I've grown with HID for years and love it. You could look in to the LEC bulbs too, like someone mentioned above, they do run a lot cooler

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Yeah I do feel more sided with HID, the gentleman/lady above me just sourced me some LEC's and they seem a little out of my budget. I think I will stick with HID.

on a tangent, I'm a little confused with something at the moment,

I am just looking at air filters and air cooled lights. They're separate products, the air filter being 4" and the air cooled reflector 6", would this mean they are unable to work in unison?