i have a grow box in my house. i upgraded to some higher wattage CFL bulbs.
im using two 42-watt warm white CFL's. totaling 5400 lumens of light for the plants..
im currently growing lemon balm, a few different coleus plants, chocolate mint, spearmint.. an unknown wild flower i picked and cloned.. and some kind of rubbery plant a snagged a cutting of from lowes :P

my plants are stretching. growing funny & ugly. and the leaves on the lemon balm have dead brown edges.. i read that using only warm white light can cause this due to not getting enough of the blue spectrum.. i also read that "warm white" is better for more mature plants.. but i have mature plants, and they were fine until i got these warm white bulbs. now their doing the same thing...

should i replace them with "cool white" or "daylight" bulbs?
ive heard daylight is the best. but i think i might need more blue spectrum to help fix these plants.... these are pictures of the lights (not as yellow as the camera made them look), how it made my chocolate mint grow, and what its doing to my lemon balm leaves.. (i guess you have to click on the image to see the full view)... but suggestions?

I don't have enough experience to say this from my own observations, but what I read agrees with what you said: insufficient blue light can sometimes cause elongation.

But that might be caused by either a too-red spectrum, or just plain not enough brightness. I think that adult plants usually need more brightness than seedlings, but others on this thread have MUCH more experience than I do.

>> two 42-watt warm white CFL's. totaling 5400 lumens of light

I have less light than that and my seedlings don't stretch out too much even though I think I have marginal overall brightness. I aim my CFL bulbs to cover 3-4 1020 trays. How much area are your 5400 lumens spread over?

I do think that adding or replacing one or both warm bulbs with daylight or "cool" or "bluish" bulbs would help you.

oh i just have them in a small plant box i built using cheap partical board lol.

its about a 3 foot square box, lights are about 2.5 feet from the tops of the plants.

heres a picture of it... kinda sad i know, but for now its all i can do. i had to make it because i dont have an extra closet haha..

"Improvised" is great! And reflectors are smart. I don't think that seedlings and plants care very much about "fancy" and "pretty".

The reflecting glare makes it LOOK like a lot of light!

At first I was going to speculate that the brown/necrotic leaf edges were caused by dry indoor air, but the way that box is enclosed suggests plenty of humidity. Is there enough air circulation to keep it cool?

BTW, I use sheetrock/gypsum board/drywall under my trays so that when I use a heating mat, I don't lose heat straight down. I mostly start seeds during cold weather, and that room is very cold.

haha thanks rick :D

and yea i dont think it gets too dry in there.. i also mist them pretty often. at least 3 times a day..when i dont have much else to do but look at my plats :P
not sure if misting them too much is bad or not...

it does get cold in here sometimes.. i live in the worst room in the house when it comes to getting cold. i live with family.. and they give me the sun room with 6 windows in it that leak -_-

it gets down to 60 degrees in here in the coldest days of winter.. but the plant box usually stays about 5 degrees warmer than the rest of the room. i keep a thermometer in there.
hard wood floors and a cold basement under me does make the floor very cold.. but the plants being in that box, they are ontop of partical board, and part of an old air mattress i cut up to use for the bottom of the plant box lol..

i probly could use a heat mat though. im just out of work right now and things are rough...
i have to wait 2 more weeks til i can get some new lights that dont make my plants into vines :P but thanks for the post rick. and thanks for the welcome post in my other posting :]

I'll just jump in here for a minute.
While you are out of work, spend some time doing research.
Use the key words 'diy heat mat with rope lights' and you will see several folks who have made this.
Be careful not to buy the 'cool' type lights; you want the ones that get warm/hot.

There is a good discussion in the comment section on this page:
https://www.google.com/imghp?h...

Good luck with everything. I keep my drafty place cold in the winter and I just wear lots of layers.

Just a couple of thoughts on your pictures, have you tried moving the lights closer to the plants? I know for seedling growth, the lights need to be as close as 6in. to the plants. Do it gradually and see if it starts to help.

When I used grow lights, I always used 'daylight'. No problems. They need the full spectrum, as close to sunlight as you can make it, not just more blue or red . . etc.

The closeup of your mint leaf with the burnt edges, could that be fertilizer burn? When the 'weather' is cooler, the plants grow slower, so if you haven't tapered back on fertilizer as it cooled off you might try that also.

Plants only use a relatively narrow part of the visible light spectrum with one peak around 430nm (red) and the other around 660nm (on the border between blue and violet). If your lights aren't putting out those parts of the spectrum, the plant is essentially sitting in the dark, no matter how bright the lights are.

well i dont think the plants are sitting in the dark when it comes to spectrum, the do grow towards the light, so im pretty sure the lights are making them grow :P
but somethings wrong for sure... and fertilizer burn?? i dont think so.. i mean its regular miracle grow potting mix, and they did fine until i got them under these lights.
but thank you for your comments guys.... so daylight bulbs would be the best eh?
instead of one cool white, and one warm white bulb??

Alex:

Can you share the plants you are interested in growing. I can always spare a spider plant, and a succulent or two. I think your grow box is pretty great actually. If you put reflective material on the surface beneath your plants the reflective light will be a nice boost. Share what plants you are hoping to grow, I know If I have something I will gladly share.

@lauriebasler, this thread is 3 years old and Alex hasn't posted on the site since Nov. 2014.

Only when I have searched too long for info I really need, do I get caught in this stupid mistake. This post distracted me, something about Alex pulled at my heart strings and mamma bear came out. I would love to how Alex is today. I realized it was old too late. but thank you.