Philips Light for seedlings question

[jhouse]

Hi all,

I started seedlings this year (various tomatoes, jalapenos, basil) after not gardening for several years.

I got out my "lighting rig", the bulbs still work -- I am very confused after reading about different lights for seedlings and distance from plants etc.
I have a 72 cell self watering kit, am using 2 lighting systems with 2 bulbs in each, placed a few inches apart to cover the 72 cells. Almost all the tomato seeds have germinated. The window is a west facing (little bit south), and gets pretty strong sun in late afternoon, so I lower the blind.
If anyone can shed some light on this for me, I would be very grateful
The info on the bulbs:

Philips F40T12/C50 SUPREME 40 WATT

[PhilaGardener]

Sounds like you are off to a great start.



Just keep those 40 watt tubes directly over and as close to the foliage as possible without touching and you should be fine! Raise the lights (or lower the plants) as they grow. It's harder if you want to mix sun and fluorescents, as it is hard to get the seedlings to grow straight.


Good luck!

[xellos99]

Always use natural light as much as possible, especially direct sun.

I would turn the lights off at any time there was direct sun.

You would need some seriously massive high intensity lights to do even a fraction of what direct sun puts out in lumens.

It has been very sunny for a few days in my country and the growth was incredible.

[Koala Doug]

Your florescent bulbs are T12s - those haven't been made for about five year now, so any available tubes are old stock. Keep an eye on the seedlings potentially getting leggy from weak (old) light. If that is the case, buy one of those remaining T12 tubes for your plants.



For T12s, you can put them within a couple of inches from the plant tops without too much worry. But when the sun directly hits that window, I'd keep the shades up as the springtime sun would be a better source of energy for the plants than the florescent tubes.

[Worth1]

How many people here know what the number means with T 12 T 8 and T 5 tubes?

[xellos99]

Originally Posted by Worth1

How many people here know what the number means with T 12 T 8 and T 5 tubes?

Distance between the pins I think.

Like T5 has 5mm gap ( I think )

[asaump]

T nomenclature is the diameter of the tube.

[Greatgardens]

Tube Diameter in 1/8":
T12 = 1.5"
T8 = 1"
T5 = .625"

[Worth1]

Everything you ever wanted to know about these critters.
https://en.wikipedia.org/wiki/Fluorescent_lamp_formats

[jhouse]

Well, I did get a new lighting system -- found a Hydroponic store in Dayton and purchased a Sunblaze brand high output rig, 6 lights that are T5, supposedly 30,000 lumens.
Oddly can't seem to find info on this system and how far to place the light from the seedlings, the fella at the shop said at least 12" away or more as I might burn the seedlings.
I'd welcome any further input, thanks for the info so far!

Re direct sunlight -- the only sunlight available is late afternoon sun and it gets so warm through the window I'm afraid it might burn the seedlings? Or at the least they will lean a lot. Wonder if the new lighting would be almost as good as sunlight at this point?


Jan H.

[xellos99]

Originally Posted by jhouse

Well, I did get a new lighting system -- found a Hydroponic store in Dayton and purchased a Sunblaze brand high output rig, 6 lights that are T5, supposedly 30,000 lumens.
Oddly can't seem to find info on this system and how far to place the light from the seedlings, the fella at the shop said at least 12" away or more as I might burn the seedlings.
I'd welcome any further input, thanks for the info so far!

Re direct sunlight -- the only sunlight available is late afternoon sun and it gets so warm through the window I'm afraid it might burn the seedlings? Or at the least they will lean a lot. Wonder if the new lighting would be almost as good as sunlight at this point?


Jan H.

I think it is like checking a baby bath water, you put your hand there and if the temp is comfortable for you then likely it will be comfortable for the plant.

[jhouse]

wow so simple and so smart thanks.I knew temperature was a factor but wasn't sure about the brightness of the light as well

[Worth1]

Originally Posted by xellos99

I think it is like checking a baby bath water, you put your hand there and if the temp is comfortable for you then likely it will be comfortable for the plant.

Never washed a baby in my life but my hands are like leather and can handle some real heat.
At least for me I would have to use a thermometer.

[xellos99]

Originally Posted by jhouse

wow so simple and so smart thanks.I knew temperature was a factor but wasn't sure about the brightness of the light as well

I will tell you a trick

You put a fan aimed at the side of the plants.


And it blows the heat away so you can put the lights closer for faster growth.

[jhouse]

what temp would be optimal, like 75 degrees or so?

thanks for the fan tip!