cool vs. warm fluorescents?

I'm new to DG and I've read several posts on lighting for germination and seed starting. Many of you swear by using a cool fluorescent and a warm fluorescent in tandem, but I can't seem to find a "warm" fluorescent anywhere. I'm getting this fixture with this light, but I want to add warm fluorescents:

http://www.lowes.com/lowes/lkn?action=productDetail&productId=163689-337-0605121020&lpage=none&pad=true
http://www.lowes.com/lowes/lkn?action=productDetail&productId=132655-3-24406&lpage=none

I've started my own seedlings in the past, but they always tend to come out weak and spindly, and are slow to thrive (or die!) in my garden. I usually use 2 cool white fluorescents an inch or two above the plants in a sunny room with bottom heat and humidity control.
Any suggestions as to why my plants aren't thriving or where I can find a "warm" fluorescent? Does "warm" just mean a full spectum light? Thanks!

Hi turtle girl
Full spectrum would be both warm and cool. Lowes probably has warm bulbs. They're usually sold as bathroom and laundry room bulbs. Look for a number on the package with a capital 'K' after it. Warm color temperature bulbs have a 3,000 something number (or lower...) This site explains cool and warm color temperature, and it'll give you an idea what the 'K' number means.


http://www.lightbulbsdirect.com/page/001/CTGY/ColorTemp

About your seedlings, I don't know, somebody will come along with more help, I'm sure.
Go Terps!

Or you can buy a bulb that says it is for plants. it's a bit more, but you'll be sure to get the right spectrum.
I bought a Sylvania soft white mini 19 W CFI for my desert rose (A. obesum) and it's bursting forth with leaves. GE and Sylvania and Philips have info on their websites too.

Thanks for the advice! I think I'll eat the expense and try all full spectrum bulbs this round. If it gives me healthier plants, it'll be worth it.

Oh geez, I missed the Murlend ref altogether! As a Balmorean (in exile) and Johns Hopkins alum (who summered in Westminster, them was the good old days), Blue Jays all the way. Need a repeat of the undefeated lacrosse season. got my goalie stick ready.....

Welcome to DG! :-)

Tom DeBaggio (herb grower supreme) and others have said that cool florescents are just fine for seedlings... that's what I use, and I've had excellent results. I'm not arguing with the folks who like the mix of warm and cool lights or the "grow lights," because different things work for different people, but I'm not sure your past seedlings have failed to flourish because of a lighting problem... Cool florescent tubes an inch or two above the seedlings should make them very happy. Before you spend $$ on grow lights, let's see if there's anything else that could be causing the problems you've seen.

Although they're great for many things, not all seedlings love bottom heat... For example, tomatoes should come off the heat mat after the first seed has sprouted, or you'll end up with spindly, leggy seedlings. What are you growing with bottom heat?

What kind of potting mix are you using? Are you using a mix with peat moss or coir, perlite, etc, or are you using garden soil? Are you adding fertilizer, moisture crystals, or other things to your mix?

How are you watering (from the top or from the bottom by putting water into a tray that the pots sit in), and how often are you watering? Do you get seedling death like damping off (sudden death due to any of a variety of pathogens), or do your seedlings just look wimpy?

I've posted a bunch of information here about things I do when starting seeds.... maybe something in it will be helpful to you. http://davesgarden.com/forums/t/589725/

Has this become the Murlind hang-out on DG? How'ya doin, Critter?

I only use the cool ones for starting seedlings.


This message was edited Feb 9, 2007 5:56 AM

Great link, Critter!


This message was edited Feb 9, 2007 5:56 AM

Prism, I agree, although I know that the "warm" bulbs have their advocates even for seedlings.... I just don't think the light source is the cause of turtle girl's problems with her seedlings.

BB, thanks, I'm doing fine -- but I need to get started sowing seeds! I've got a bunch of wintersowing to do (turtle, see the wintersowing forum for an explanation of that term and an intro to another exciting way of starting seeds), plus I need to start a few slower things like impatiens and torenia.

Prism, glad you found some good info there... most of what I do, I learned from Tom DeBaggio's books, and the rest I picked up here on DG!

The lumens (brightness of the bulb) are more important than the spectrum. A bulb used for more than a year is much weaker than a new one (try a new and old one side by side) lumen ratings are usually on the box the"plus" bulbs are usually rated higher.

Hey All!
Thanks for all your input. I've got everything set up now and will be sowing seeds this weekend. I bought the Lowe's wire shelves with three Agrosun double 4-foot fixtures and Agrosun full spectrum bulbs (40 watt, 2200 lumen, 6400K color per bulb). I also got a couple of the HydroFarm Hot Houses with heat mats. The humidity domes on these things are flimsy and cheap, considering the cost, but I think they'll work out okay. I'll probably start with shorter humidity domes until my seedlings get bigger so I can get the lights closer, then switch to the taller Hot House domes. I'll let you know how it works out.

Critterologist--I think I found my previous probem: I looked at my old lights. They were WARM white and too old. I was also moving my plants to a large SE facing window when they got too big to fit under my lights (2-single tube 3 ft. bulbs). I'm hoping this was the cause of my problem.
In answer to your questions: I'm growing a large mix of vegetable, herbs, and beneficial flowers...FAR too many to list. :-) I only use heat to help germinate seeds that need 75+ degrees for germination, then turn it off once that is achieved. I used to use plain peat for seed starting, but this round I'm going to try the Miracle Grow seed starting mix with your suggested sterilization technique (thanks!). I always bottom-water and have never had many problems with damping off or die offs. My seedlings always just looked wimpy, though I think this was due to my afore mentioned lighting problems.

Claypa and BBinnj-- LOL...actually, the turtle girl reference is to my profession, though I did get my bachelors from UMD (go Terps!). I'm a Wildlife Manager who is currently working to study and protect Eastern Box Turtles. I love my job!

That setup looks very familar - same one as mine but I have two sets of lights for every shelf. Guess it depends on how many flats you are going to stick under there. I also rotate my flats cause one side is next to a window and grows faster.

What did you sow?

-Kim

Can I use a full spectrum light, the kind you buy at the craft stores (I got mine at JoAnn Fabric), for seed starting? I bought this light for drawing, but it has always reminded me of growing something in a clandestine corner, but that's just me, LOL.