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View Full Version : Grow light time-of-use question.


Want Them All
12-21-2009, 12:28 PM
I have my light set up to run 15 hours/day, from 7 PM to 10 AM. I'm curious about the effect of having the plants exposed to light in an "abnormal" cycle. In nature, they get light during the daylight hours, but now when it's supposed to be dark, they get light, and the rest of the time, it's dark in my garage, when it's daylight hours outside the house. My reasons for having my light on from 7 PM to 10 AM are twofold:

[1] From 6PM to noon, my electricity rates are the lowest, I'm on a tiered arrangement with the electricity company, not a flat rate.

[2] At night it's colder, so the grow light, in addition to providing the light for growth, also keeps the plants warm (78-83 F)

Do you think the plants will have trouble adapting to the natural cycle of day & night once springtime comes and they go outside?

Thanks,

jwmahloch
12-21-2009, 02:22 PM
I dont think it will harm your plants to have the grow light on at night. I have my grow lights on during the day on a timer set for 14 hours. I think the most important thing in the spring is to gradually move plants back to the sun outside (harden off). It depends on the plant. Banana plants really dont seem to mind the change from inside light to full sun outdoors but some palms and tropicals plants need to be hardened off. Good luck

Want Them All
12-21-2009, 02:52 PM
Thanks Jeremy,
the plants in queston are plumerias.

Dean W.
12-21-2009, 06:33 PM
Great question! I don't think it will harm them either.

I bought a couple of grow lights today. Maybe I can keep my Caldomin leaves green and use the other to start some seeds in a few months (haven't decided yet).:2722:

jwmahloch
12-21-2009, 08:05 PM
One thing I have learned with the grow lights is: get the plants as close as possible to the light. and it doesnt harm banana leaves to touch floressant lights.

I actually have 2 banana plants that are up to my ceiling in my basement, taller than the grow lights. I have been just guiding the leaves in the right direction and they are ok for now. The 2 plants are still putting out new leaves every 2 weeks about 3 feet long. I have backed off a lot on the water.

Want Them All
12-21-2009, 10:13 PM
You're OK to have your plants close to the light because your lights are fluorescents. Mine would burn, I have HID light, quite hot to the touch.

serial_killer
12-22-2009, 01:16 AM
If you had it in a cool tube with proper ventilation it wouldnt be to hot to touch the plants. I have a 400W HPS in a 6 inch cool tube with a 250CFM exhaust fan and I can lay my hand on the glass directly under the light, its warm but at no point does it become uncomfy, I could hold it there all day if I wanted. Bigger light = more CFM.

jakesebastin
06-21-2012, 08:44 AM
I do not think it will harm your plants. Generally each and everyone have the grow light on at night. The most important thing in the spring is to gradually move plants back to the sun outside.

cincinnana
10-28-2019, 03:44 AM
Now's the time to set those timers.:woohoonaner:

paulorph
10-28-2019, 07:31 AM
Now's the time to set those timers.:woohoonaner:
Sad but true. Took plants in at Moms house into basement with grow lights and time. Do a 11 or 12 hour cycle. They will miss the outside....