Four foot two T8 bulb fixture coverage

Salaam · February 17, 2021

Hello all,

It's been a few years since I started seeds as a novice and I have a question for those more experienced. I have 4 ft long 18 inches wide shelves that I'm planning to cover with a pair of 4ft T8 bulb fixtures. Each fixture has two bulbs, making for a total of 4 bulbs for one shelf. The total width of the two fixtures is about 10 inches. Will these two fixtures adequately cover the 18 inch wide shelf, or do I need a third fixture per shelf?

Also, does anyone have experience with lights like https://www.amazon.ca/gp/aw/d/B07RRV...WZ95494&psc=1?

simmran1 · February 17, 2021

Salaam, I don't have experience with LED's like shown on the link, but the coverage is 3x3 feet.
I think with your shelves being 4x1.5 ft you'd be better off with your original plan to use the T8 lamps. Of course they should have a kelvin of 5000k +/-.

The shop light reflector, or shade comes into play as well, but I see no reason why 4 lamps of the right lumens and spectrum wouldn't be perfect for your shelves.

GoDawgs · February 17, 2021

I have 18" wide shelves and hang two T8 shop lights over each shelf and they work just fine for me. I use one 3000k and one 6500k tube (not LED) in each fixture to try to provide a wider light spectrum. It does mean turning trays of plants around every day as they slightly lean toward the stronger tube but I don't mind as I use the time to check watering and plant health. Been using these for years.

Granted, I place the plants in a line directly under each fixture and don't cover the whole shelf with plants so you could say there's some unused area. But I've never tried doing that so I can't say plants in the middle wouldn't have enough light. There would be room for a third fixture if the fixture had a narrow reflector.

Salaam · February 18, 2021

Thanks all. I think I have exactly the same shelf as you, GoDawgs I'll use two fixtures (four bulbs) per shelf and if the plants on the edges of the shelf aren't doing too well, I'll try and make some room in the middle or something.

I'm considering the LED lamp not for these shelves, but for a folding table for additional seedlings, or for moving some seedlings that have grown too tall for the shelf setup or that are not getting enough light in the shelf setup.

I hope I have somewhere to plant all these seedlings if everything works out!!

KarenO · February 18, 2021

Very similar to what I use for seed starting and I find it works well. I have mine set up in front of a large south window and find that helps considerably as well. Even with the lights on all day, the seedlings lean toward mother sun. They know

KarenO

Salaam · February 18, 2021

Karen, the one and only year I started seeds they were next to the south-facing window and I think they benefited quite a lot. Alas now they'll be in my garage with not too much light from the door window.

NathanP · February 19, 2021

I use maxlite LED tube lights with either 2 or 3 fixtures per shelf, depending on what I am growing. Tomatoes should do fine with just two. Mine are a slightly lower lumen version of this.

https://www.amazon.com/MaxLite-Linka...3784324&sr=8-3

February 17, 2021	#1
Salaam Tomatovillian™ Join Date: Mar 2012 Location: Ottawa, ON Posts: 128	Four foot two T8 bulb fixture coverage Hello all, It's been a few years since I started seeds as a novice and I have a question for those more experienced. I have 4 ft long 18 inches wide shelves that I'm planning to cover with a pair of 4ft T8 bulb fixtures. Each fixture has two bulbs, making for a total of 4 bulbs for one shelf. The total width of the two fixtures is about 10 inches. Will these two fixtures adequately cover the 18 inch wide shelf, or do I need a third fixture per shelf? Also, does anyone have experience with lights like https://www.amazon.ca/gp/aw/d/B07RRV...WZ95494&psc=1?

February 17, 2021	#2
simmran1 Tomatovillian™ Join Date: Nov 2008 Location: Iowa Zone 5 Posts: 305	Salaam, I don't have experience with LED's like shown on the link, but the coverage is 3x3 feet. I think with your shelves being 4x1.5 ft you'd be better off with your original plan to use the T8 lamps. Of course they should have a kelvin of 5000k +/-. The shop light reflector, or shade comes into play as well, but I see no reason why 4 lamps of the right lumens and spectrum wouldn't be perfect for your shelves. __________________ Tomatovillain

February 17, 2021	#3
GoDawgs Tomatovillian™ Join Date: Feb 2018 Location: Augusta area, Georgia, 8a/7b Posts: 1,685	I have 18" wide shelves and hang two T8 shop lights over each shelf and they work just fine for me. I use one 3000k and one 6500k tube (not LED) in each fixture to try to provide a wider light spectrum. It does mean turning trays of plants around every day as they slightly lean toward the stronger tube but I don't mind as I use the time to check watering and plant health. Been using these for years. Granted, I place the plants in a line directly under each fixture and don't cover the whole shelf with plants so you could say there's some unused area. But I've never tried doing that so I can't say plants in the middle wouldn't have enough light. There would be room for a third fixture if the fixture had a narrow reflector. Last edited by GoDawgs; February 17, 2021 at 07:08 PM.

February 18, 2021	#4
Salaam Tomatovillian™ Join Date: Mar 2012 Location: Ottawa, ON Posts: 128	Thanks all. I think I have exactly the same shelf as you, GoDawgs I'll use two fixtures (four bulbs) per shelf and if the plants on the edges of the shelf aren't doing too well, I'll try and make some room in the middle or something. I'm considering the LED lamp not for these shelves, but for a folding table for additional seedlings, or for moving some seedlings that have grown too tall for the shelf setup or that are not getting enough light in the shelf setup. I hope I have somewhere to plant all these seedlings if everything works out!!

February 18, 2021	#5
KarenO Tomatovillian™ Join Date: Oct 2012 Location: Vancouver Island Posts: 5,931	Very similar to what I use for seed starting and I find it works well. I have mine set up in front of a large south window and find that helps considerably as well. Even with the lights on all day, the seedlings lean toward mother sun. They know KarenO

February 19, 2021	#7
NathanP Tomatovillian™ Join Date: May 2013 Location: RI Posts: 183	I use maxlite LED tube lights with either 2 or 3 fixtures per shelf, depending on what I am growing. Tomatoes should do fine with just two. Mine are a slightly lower lumen version of this. https://www.amazon.com/MaxLite-Linka...3784324&sr=8-3