Most useful lighting for highschool greenhouse

[Aaron]

The new greenhouse will soon be completed (15 x 57) not including a 15x57 "prep room" in the second floor of my high school. We are planning on a Murray-esq flood drain system with a raisable double bunkbed system. I thought the T5 HO lights would be best for the widest variet of plants and best for not burning students. I'm interested in the communities thoughts on the subject.

[TCLynx]

Well I noticed that the growing power lower "bunks" had simple florescent shop lights installed under the top bunk.  Since they were only growing water cress in the lower bunk it seemed to work fine.  The stuff up top got sun.

 

If using florescent lighting for anything other than just minimal supplement the way growing power is, I highly suggest making the lighting fixtures adjustable so you can place them as close to the plants as possible and raise them up as the plants grow to get the best growth.  this of course means the plants under a fixture need to all be about the same size and you need lights over pretty much the entire footprint of the growing space.  If the lights are more than a few inches from the leaves, they are only minimally effective.

[Aaron]

Ok, I like your thinking on this!  I will make it a point to get the lights below the top bunk and leave the top ones open to the ambient light of the greenhouse.  I am still interested in the T5 HO's until I can look at the UV output / cost / interchangability of the set up.  I know normal florescent lights have little to no heat index which is a primary concern considering the students.  Thanks!  

TCLynx said:

Well I noticed that the growing power lower "bunks" had simple florescent shop lights installed under the top bunk.  Since they were only growing water cress in the lower bunk it seemed to work fine.  The stuff up top got sun.

 

If using florescent lighting for anything other than just minimal supplement the way growing power is, I highly suggest making the lighting fixtures adjustable so you can place them as close to the plants as possible and raise them up as the plants grow to get the best growth.  this of course means the plants under a fixture need to all be about the same size and you need lights over pretty much the entire footprint of the growing space.  If the lights are more than a few inches from the leaves, they are only minimally effective.

[TCLynx]

yea, little/no worry with burns from a florescent

 

[Chi Ma]

I'd get them for above the grow beds too Aaron. School is usually in session when the days are shorter and overcast. 

Aaron said:

Ok, I like your thinking on this!  I will make it a point to get the lights below the top bunk and leave the top ones open to the ambient light of the greenhouse.  I am still interested in the T5 HO's until I can look at the UV output / cost / interchangability of the set up.  I know normal florescent lights have little to no heat index which is a primary concern considering the students.  Thanks!  

[TCLynx]

Well, if you are gonna put any lights way up high and not impede larger plants in the top beds or block what little natural light there is, I would recommend a few of the Metal halide or HPS lights up high for winter supplementation.  Since they would be in the peak, they wouldn't be dangerous to the kids.

[Aaron]

Thanks guys!  Tomorrow I'm going to recommend using regular t12 florescent lights (which are in abundance at our school) and save our money. Thanks for the advice all!

[Chi Ma]

They are phased out T12 in July of 2010. T12 ballasts will no longer be produced and they will stop production of T12 bulbs by 2012.

T12 Phaseout

[Aaron]

Oh crap!  Good to know so is it T5 HO or bust?  Keep in mind this is in a glass greenhouse that will have abundant light.  This is only supplemental lighting for the short darker days in winter.

Chi Ma said:

They are phased out T12 in July of 2010. T12 ballasts will no longer be produced and they will stop production of T12 bulbs by 2012.

T12 Phaseout

[Chi Ma]

No. You can use T8. T5HO is just the future :)

Aaron said:

Oh crap!  Good to know so is it T5 HO or bust?  Keep in mind this is in a glass greenhouse that will have abundant light.  This is only supplemental lighting for the short darker days in winter.

 

[Aaron]

Peter. FYI the greenhouse is in south jersey. Maybe a few metal halides high up wouldn't be so bad for supplemental light but it comes down to my grow bed set up. If I do bunk bed I will need t5 or t8 on the bottom. If I do a single level Grow bed the metal halides will do the trick.

[Aaron]

just got out of meeting where we were told that the school is installing high pressure sodium lights that are permanently mounted to the ceiling!  There will be a huge gap between the tops of the plants and the lights.  We will get 10 ballasts though.  I think this is bad news!

[TCLynx]

Since it is just for supplement, I don't think it is so bad.  HPS lights are used in hydroponic lighting through they are more commonly used for fruiting stage of growth.  Perhaps do some research into what lamp color temperatures are available for the fixtures they are installing.

Aaron said:

just got out of meeting where we were told that the school is installing high pressure sodium lights that are permanently mounted to the ceiling!  There will be a huge gap between the tops of the plants and the lights.  We will get 10 ballasts though.  I think this is bad news!