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Are CFL Grow Lights Effective?

Posted July 5th, 2016 by Robin Nichols in

CFL Grow LightCan you grow with CFL Grow Lights? The simple answer is yes. The complicated answer is it depends on what you’re growing and what you are trying to achieve. Most beginning indoor gardeners want to grow in the cheapest and easiest possible way. This makes sense, nobody wants to buy more than they need and waste their hard earned money. But before you can get started a grower needs to decide what they will be growing.

Uses for CFL Grow Lights

CFL Grow lights are great for many things, for instance a 125 watt CFL is great for starting seeds or cuttings.  The 125 watt CFL keeps the seedlings from becoming leggy and has a large enough footprint that you can put more than one tray directly beneath it.

CFL grow lights can also be very effective for growing plants from seedling to full vegetative stage as well. They are excellent for growing greens and save money by using a minimal amount of electricity. However, if you are growing larger plants additional bulbs may be needed to ensure there is enough light.

CFL Grow Light Wattage

The most common CFL grow lights are 25 watt bulbs that screw into medium base sockets (your standard household bulb socket) or larger 125 watt mogul base CFL bulbs. There are other sizes as well, but these are the most common. The 25 watt CFLs are pretty small and most often used for growing single plants. Typically you’ll start the seedling with a 25 watt, wait until it grows a little larger, add another, rinse and repeat. It normally requires four 25 watt CFLs to grow a healthy medium size plant.

There are larger CFLs available but the price compared to the wattage output normally makes them less attractive to use. For example, a 125 watt CFL is normally priced $30-40 range, while a 200 watt sells for $60-70. The price per watt of the 125 watt is significantly lower than the 200 watt. You’ll have to make a one-time purchase for another socket or reflector if you need more than a 125 watt, but in the long run you’ll save!

Spectrums of CFL Grow Lights

CFL Grow Lights typically have two spectrums – 6500k for grow and 2900k for bloom. Small CFLs like a 25 watt are usually only available in 6500k. The 125 watt models are normally offered in both 6500k and 2900k, but occasionally you may see a dual spectrum bulb that contains components for both.

Can I use CFLs for the Bloom Stage?

Technically a CFL grow light can be used for the blooming stage, but you need to understand what results you are trying to achieve. A single 125 watt bloom CFL will not produce a great harvest, but if the yield isn’t that important and you’re comfortable taking the “something is better than nothing” approach they will work. However, if a larger harvest is important then it is best to go with at least two 125 wayy bloom CFLs for a single plant. The overall quality can be good using either method, but a single 125 watt will not provide a big yield or density.

Final Verdict

CFLs have their uses, and you can grow a full plant for seed to harvest under them, but they may not be best for all stages of growth. CFLs work well for starting seeds or cuttings as well as the early vegetative stage, but for large plants and the flowering stage it is best to use high intensity lights like HID (MH/HPS) or LED. Don’t be discouraged if you decide to use CFLs, just don’t expect extremely high yields. If using a CFL is the only option, by all means use one, because growing something is definitely better than not growing anything at all.

Background information for this article was provided by Rogue Hydro. Learn more about them at RogueHydro.com.

Want more information? Try these articles:

7 Keys to Success with LED Grow Lights

Comparing T5 and T8 Grow Lights for Indoor Gardening

Lumens and Grow Lights

The Advantages of Using a Combination of LED and HPS Lights

Why High Intensity Discharge (HID) Grow Lights Remain Popular

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