When I was a beginner gardener, I made a lot of mistakes and spent too much money on products that were supposed to ensure success in the garden but didn’t.
This was especially true with anything involving indoor plants or indoor gardening, particularly with starting seeds.
I learned to keep things simple and to invest only in products that truly made a difference because it respected what plants needed to grow.
Correct lighting is one of those things.
You have to buy the right lights in order to see your seedling establish roots, sprout and begin to leaf out.
Nothing was more frustrating and discouraging than trying to start seeds indoors under lamps with the wrong type of bulbs!
To save you time, money and heartache, I presented on “Grow Lights 101” recently on the Home & Family show on the Hallmark Channel.
Below is an informal transcript of the segment with a little added information that was not mentioned on camera because of time constraints.
Before I share my opinion on what bulbs are best for starting plants, let’s take a look at some essential facts so you can understand the process of imitating sunlight with bulbs.
Although you can use any kind of light bulb to supplement light to a plant, not all light bulbs provide the specific light spectrum that plants need to grow.
Watch my garden video segment on Indoor Lighting on the Home & Family show in the video above.
UNDERSTANDING LIGHT COLOR OR SPECTRUM (KELVIN TEMPERATURE)
If you were to look at sunlight through a prism, you would find a full spectrum of colors ranging from infrared (red) to ultraviolet (blue).
Through the process of photosynthesis, a plant absorbs the sun’s light and transforms it into life sustaining energy in order for it to grow, fruit and flower.
Plants are also very specific about what they need in order to thrive during the different phases of their growth cycle.
Color spectrum or color temperature is measured in Kelvin units, designating colors as “warm” through “cool.”
Bulbs with an output of 3500K or lower on the scale will have an amber hue (red/orange).
Bulbs between 3500K-4100K will have a white hue (cool white).
Bulbs in the higher 4200K+ range will have a more blue hue which is similar to or exceeds that of sunlight.
To make things easier for the consumer, lighting companies have adopted the custom of labeling their packages for bulbs as “warm white,” “bright white” or “daylight.”
This is their Kelvin For Dummies shortcut so you don’t have to read the scale on the back of the package that discloses the Kelvin units for the bulb!
Kelvin units are printed on the box, so look for them when buying grow lights.
Seedlings need to absorb blue wavelength color during the beginning of life.
The blue spectrum is responsible for leafy, green growth, typical of emerging plants, especially herbs and vegetables.
Many gardeners in cold winter areas who want to start vegetable plants indoors need to know about this.
Vegetable plants that grow fruit tap into the red spectrum in sunlight, providing the necessary punch (not sure if pun is intended or not) for fruit to set and mature.
FULL SPECTRUM LIGHT?
Needless to say, artificial light provided by bulbs usually do not mimic the full spectrum of color (at least not the bulbs I recommend to beginner growers).
Light bulbs for indoor growing provide a specific spectrum of light needed for a stage of life of the plant.
Buy a bulb with a cool or “blue” color spectrum.
Buy a bulb with A red/orange color spectrum.
LIGHT INTENSITY OR BRIGHTNESS: LUMENS
Don’t shop for bright lights based on wattage; that’s old school!
The number of “lumens” is what you should be paying attention to.
The higher number lumen rating, the brighter a bulb will be.
With the introduction of energy efficient bulbs, watts only indicate how much electricity it takes to run a bulb, not how bright it is!
You can now have a bulb with a high lumen rating and small watt indication.
Now that the basic color spectrum facts are disclosed, I’ll move on to the bulbs that are recommended for starting plants indoors.
WHAT LIGHT BULBS WORK BEST AS PLANT GROW LIGHTS?
There are more than four different types of light bulbs available for growing plants indoors, but I’m focusing on the most common and affordable ones.
Two of these bulb types are on my “don’t buy” list, while the other two are on my “do buy” list.
DON’T BUY THESE BULBS FOR GROWING PLANTS INDOORS!
Halogen lights provide bright light but also give off excessive heat which can burn plants.
Steer clear of halogen lights unless you are in need of a torch!
Incandescent light bulbs have had their time to shine since Thomas Edison invented them over 130 years ago.
Although Edison’s invention was brilliant, the inefficient use of electricity has sparked innovations in the lighting world.
Incandescent light bulbs give off too much heat for the small amount of light they provide.
They are also plant scorchers!
Energy use is measured in WATTS, and incandescent lights use too many!
Don’t be swayed by the low price tag for these bulbs.
It’s a fire sale!
(I can’t believe all the puns I was able to work in for incandescent bulbs).
Goodbye incandescent lights, I’m turning you off in my indoor garden!
BUY THESE BULBS FOR GROWING PLANTS INDOORS!
LED LIGHTS (LIGHT EMITTING DIODES)
Long story short version:
LED lights use less energy and stay cooler than the other two light bulbs and come in full spectrum light or isolated blue or red color range.
Yes, LED lights are more expensive than all the others mentioned above, but they are longer lasting and use up to 60% less energy.
HIGH OUTPUT FLUORESCENT LIGHTS (HO Fluorescent)
Either a T-5 fluorescent light bulb (the long, skinny shop light type bulbs) or a compact florescent bulb is a winner for starting seeds under lights.
- HO fluorescent lights come in different light spectrums to allow for customization of light spectrum.
- HO fluorescent lamps emit very little heat, allowing you to hang the fixture very close to the plant canopy.
- T5 bulbs have an outstanding 24,000 hour life expectancy (one year is 8,760 hours).
THE HYDROFARM JUMP START GROW LIGHT KIT!
This is my pick for the beginning gardener who wants to start their plants indoors.
I like HydroFarm products so much that I called them up and asked them to sponsor a giveaway on the Home & Family Show!
They enthusiastically agreed to provide 5 winners with grow light kits!
The reasons I like the Hydrofarm Jump Start Grow Light for beginners:
- Easy to assemble with no tools
- Price is under $90 for a four-foot setup including lights- you can grow many plants under these lights.
- Uses energy efficient T-5 HO Fluorescent bulbs
- Adjustable light height
- No brainer, just add plants
If you aren’t up for a setup like this, you can always buy HO compact fluorescent bulbs and put them in a clip on shop light.
HOW LONG SHOULD GROW LIGHTS BE ON ?
Length of light time depends on what you are growing.
Most vegetable seedlings need 14- 18 hours of light per day to establish roots and grow primary leaves.
I recommend you use an automatic timer unless you want to be connected at the hip with your indoor lights!
Timers run anywhere from $10 for a “one station” setup to more for more sophisticated systems.
HOW FAR DO YOU KEEP FLUORESCENT LIGHTS FROM STARTER PLANTS?
Your non-heat-emitting HO fluorescent bulb should be placed 2-4 inches from plant top.
As plants grow, lift the lights up using the pulley system of the Jump Start Grow Light kit.
You’ll know that you placed the lights too far away from plants if they grow spindly instead of full and leafy.
WHY USE GROW LIGHTS?
Besides winning the admiration of curious onlookers, using grow lights to start your plants indoors offers many benefits:
1) Grow plants throughout the cold winter and get a leg up on spring vegetable plants.
2) Grow plants that are out of season or that you are overwintering indoors and need more sunlight.
3) Grow plants in dark rooms like a garage or basement.
I hope this primer on using grow lights for your indoor plants has helped you understand how to select bulbs.
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Very illuminating post, Shirley! 🙂 I’ve had a big Hydrofarm sodium light fixture in the basement for years, for overwintering tropical and tender plants, with a florescent shop light fixture on a table next to it for seed starting. It’s not the best but it (sort of) does the job. I think having it next to the sodium light helps somewhat. I’d sure love to win one of your giveaway Jump Start Grow Light kits! My seedlings and I thank you for the opportunity!
Thank you for reading the post and commenting. I do think the sodium light helps your fluorescent illuminate things for the better.
Good luck in the drawing!
I’ve started making a flower garden in the house. I had to learn how to grow my garden to quickly and save time. And I have used LEDs. Wow. !!! and the results were amazing. My flower garden grow faster using fluorescent bulbs and save a lot of money