How Many CFLs Per Plant?

When purchasing CFL bulbs for your cannabis garden, wattage should always be taken into consideration. For maximum yields, at least 150W worth of bulbs is required per plant for maximum productivity; this equates to 6 small 23-26W bulbs or 4 medium 40-42W ones.

Knowing the difference between wattage and lumens is equally as essential; oftentimes the labeled wattage on packages can be misleading.


There are various lights you can use to grow marijuana, each offering their own set of advantages and disadvantages. Some growers swear by HID (HPS/MH), others prefer LED technology or CFL bulbs while still others use both approaches together for optimal results. Whatever kind of lighting system you decide upon for your marijuana plants, be sure to understand exactly how many watts each plant requires in order to see success.

Wattage refers to the power consumption of bulbs and is measured in watts per hour. The value should typically be printed on their package or somewhere easily accessible for easy reference; higher wattages use more energy and generate more heat, with increasing wattages using more electricity while creating heat emissions. To know if a bulb is efficient enough, dividing its lumen output by its wattage value gives an indication of this information.

For small spaces, low wattage CFL bulbs tend to be the best solution, providing great light penetration while helping keep your grow tent cool. For larger spaces however, higher-wattage bulbs might be necessary in order to avoid overheating your grow room.

CFLs may not be the most energy-efficient lighting option available, but they’re still an economical solution for smaller spaces or those without enough money to buy more costly HPS and LED bulbs. Plus, when coupled with a timer they can help adjust to meet the various stages of plant development more effectively.

Keep in mind that CFLs don’t produce as much light as other forms of illumination, so using a reflector or light-directing device is crucial to optimizing how much illumination reaches your plants and increasing yields. Furthermore, switching to Cool White (Daylight) color temperature once your flowers begin flowering as this provides additional blue lighting which encourages fruit production. A good rule of thumb would be using 150W worth of CFL bulbs per plant; which translates to 6 small 23-26W bulbs or 4 medium 40-42W bulbs per plant.

Color Temperature

Color temperature is a system for assigning numerical values to various colors on a spectrum, from warm (red/orange) to cool (blue). Measured in degrees Kelvin, this temperature reflects how radiative materials produce light of certain wavelengths.

Understanding the color temperature of your bulbs is vitally important for plant growth, particularly marijuana plants that require specific spectrums of blue and red light to flourish. CFL bulbs designed specifically for growing marijuana may provide this light; the best way to do this would be buying one specifically labelled for growing weed.

Wattage is another key consideration when determining how many CFL bulbs to use in your marijuana garden. A higher wattage bulb will produce brighter light output and help your plants absorb more light to increase yields and produce greater harvests; but remember, that doesn’t always equate with light output!

CFL bulbs that resemble natural sunlight, such as 6500K bulbs, are ideal for vegetating. You’ll find these at most hydroponic stores. When it comes to flowering stage lighting, 2700K bulbs emit warmer orange hues that help transition plants to adulthood stage more smoothly.

Consider looking at your bulbs’ lumens rating to gain a more accurate idea of the amount of light they will provide; this value will be listed on their packaging. Generally speaking, for best results use at least 10,000 lumens per plant in order to provide enough illumination.

Notably, plant needs vary throughout their lifecycle and, to meet them adequately, you will require more CFLs during vegging than flowering; red and blue light is needed during vegging while more yellow/green hues will help your plants bloom successfully in flowering mode. It is therefore vital that you follow your schedules closely; otherwise your plants might never reach their full potential!


CFLs can be an ideal lighting option for those wanting to grow plants in their home or office without having the space or time for setting up HID (HPS, MH), LED, or similar lights. Not only are they cheaper and generate less heat than their alternatives, they’re also much simpler for setting up. Unfortunately though, CFLs do have some drawbacks; not producing as many lumens compared with other lighting sources and not suitable for flowering plants which require greater illumination than they provide.

The number of watts consumed by your bulb is an essential element to its light output, and should play an essential part in its ability to illuminate your plant. As more light comes through with more wattage being consumed by each bulb. You should strive to use as high a wattage possible without overheating your space – the packaging usually indicates this number as an important indicator.

Consideration must also be given to the color temperature of a bulb, which is determined by its wavelengths of visible light emitted by it. An ideal grow light would emit wavelengths that closely resemble that of sunlight – this will enable your plants to absorb more usable light for photosynthesis. Kelvin measures color temperature; lower numbers represent warmer hues. CFLs designed specifically for growing marijuana should fall between 2700K to 6500K for optimal performance.

Kelvin rating is essential when it comes to both vegetative and flowering stages of plant development, since each requires its own spectrum of light. Vegetative plants require more blue and red wavelengths while flowers need orange and yellow wavelengths in their spectrum for proper flower development.

When selecting the appropriate wattage for your garden, the distance between bulbs and plants should also be taken into consideration. Too-close bulbs cannot properly illuminate plants; rather, you should place bulbs 4-6 inches from plants so as to avoid burning them out. Furthermore, reflectors can redirect some of the light emitted by bulbs onto specific parts of your garden.

Energy Efficiency

CFLs use one-fifth to one-third the electricity consumed by standard incandescent bulbs and typically last eight-15 times longer, as well as contain toxic mercury that must be handled and disposed of responsibly when they reach the end of their lives. Many companies have implemented systems to recapture mercury vapor from used CFLs for recycling; such measures might include negative pressure ventilation systems with cold traps for capture purposes; while some cities are using machines which crush bulbs into pieces before collecting glass, metals, and mercury for recycling purposes.

Energy efficiency of bulbs is measured in terms of lumens produced per watt of electricity consumed, as indicated on their packaging. As luminosity changes over time with ageing bulbs, lumens should be stated at their “peak performance,” not the start of life for an accurate assessment.

CFLs have become a key tool in efforts to reduce electricity use. Distributed directly or via programs provided by electric utilities or local governments, many organizations promote them as an efficient means to do just that. Some even require residents switch to CFL bulbs as part of an energy conservation initiative offered by their utility provider.

These groups argue that switching to CFLs could save enough electricity to offset Hg emissions from coal plants, the primary source of Hg emissions in the US. Even if every household adopted fluorescent lighting, however, any amount saved from coal plants will likely remain minimal.

Another issue with these claims is their assumption that all energy saved will come from coal-burning power plants; while some will, other forms of electricity produce negligible amounts of mercury compared to this estimate; as a result, CFL use will likely save far more Hg than anticipated by these estimates.

Noteworthy is the fact that one CFL emits mercury at levels much higher than California standards allow; approximately 500 billion pounds of fish could be contaminated each year based on one CFL alone!

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