Compact Flourescent Light (CFL) bulbs: How to us CFL bulbs for growing weed

Wondering how you can use compact flourescent light bulbs (CFL bulbs) for growing weed?

While it is possible to use CFL bulbs to grow marijuana, it is not recommended. The load light intensity of these bulbs is not capable of producing a fool, dence crop of buds on growing weed plants.

There are a few cases though where CFL bulbs can be useful for the marijuana grower. Here is a guide outlining several ways that CFL lightbulbs can be used for growing marijuana.

Cloning: How to use CFL light bulbs to clone marijuana

Using CFL lightbulbs to grow marijuana clones is a common approach. CFL bulbs produce almost no heat in the light is gentle enough to avoid damaging delicate clones before their rooting systems have fully developed.

It is recommended that if you’re looking to grow marijuana clones with CFL lightbulbs, you buy the high wattage CFL bulbs that are specifically made for this purpose.

Of course there are workarounds available. Because phones don’t require a lot of bright light, it is possible to break up a series of 100 W CFL bulbs  in order to make an adequate light for the clones.

Just using a single 100 W CFL bulb probably doesn’t have enough light to really facilitate good growth in marijuana. If not enough light  is present, phones will tend to stretch between nodes. This results in a taller, leggier plant with less bud sites to develop.

It is important that if you were using a small amount of CFL bulbs to clone your marijuana plants, that you pay very close attention to look for signs of not enough light. If you do notice notice signs of not enough light on your young plants, try to take action quickly. It is important that your clones develop a solid root structure and maintain enough light throughout the vegetative cycle in order to facilitate great bud development during flower. You don’t want to risk stunted development at any point of the growth cycle.  Attempting to vegetate and flower marijuana using only CFL lights isn’t recommended.

Mother plants: how to use CFL bulbs to grow mother plants

If you are using CFL bulbs to clone marijuana, the chances are you’re either running a continuous perpetual harvest cycle or you are taking cuttings from a mother plant to get to clones.

Using CFL bulbs to grow mother plants of marijuana has the advantage of limiting amount of heat produced that you need to deal with in the mother room. It also really cuts down on electrical usage.

The problem is that light intensity off of CFL bulbs is not enough to grow dense, bushy plants during vegetation. Nodes will be spaced further apart with lower light intensity. Since mother plants are kept permanently in the vegetation cycle, your mother plan will have less formation of growth tips that eventually form into new clones.

This may not be a big deal assuming that you have enough ceiling height to let your plant grow tall, and that you’re not looking to take many clones that frequently.

If you are going to use CFL bulbs to grow marijuana mother plants, it is important that you make sure to have a lot of them if you are planning on running with the kind meant to replace incandescent bulbs in your home. You’ll need to string quite a few together in order to make right enough area for your plant to develop properly, and they’ll need to be close to the plant for best results.

Bottom line – while it is possible to grow marijuana mother plants using CFL lightbulbs it isn’t recommended. You would get much better results using small wattage metal halide and HPS bulbs for flowering the mother plants. For confined spaces or small mother rooms, you can use LED lightbulbs to reduce heat and electricity usage similar to a CFL bulbs would do but with better overall results assuming you get the right LEDs for growing marijuana.

Using CFL light bulbs to flower marijuana plants

It definitely is not recommended to use CFL lightbulbs to flower marijuana plants. The plants will grow but they will be very leggy due to lack of light intensity. But development will be similarly affected. There will be less budding sites, and buds will be sparse and wispy. Yes, it is possible. But…

Rather than trying to figure out how to use CFL bulbs to flower marijuana plants, it would be better to invest in a grow light more suitable for the flowering cycle of weed. Small wattage HPS high pressure sodium bulbs are a better choice then using CFL’s in tiny grow areas for flowering plants. If you are concerned about the heat output or overall electrical usage associated with HPS bulbs, you could also use LEDs for flowering with great effect.


If you’re thinking of using CFL light bulbs to grow weed plants, You would best to be use using those CFL’s during the cloning stage when the low light intensity of CFL’s would be beneficial to small marijuana plants just starting to root. You can use CFL’s to grow marijuana seeds as well.

It isn’t recommended to use CFL light bulbs for growing marijuana during the vegetative or flowering stages. The lack of light intensity means the resulting plant will not be thickly populated with budding sites, and any resulting buds will be thin and wispy and not have a lot of mass to them.

It’s also possible to use CFL bulbs for marijuana mother plant grow rooms, assuming that you have space for a taller plan with less growth tips that can be later cut for clones.

Just keep in mind that it takes just as much work to grow really nice marijuana with the right lighting that it would take to grow fairly poor marijuana using not enough light intensity from CFL bulbs. Do yourself a favor and do some research before you grow and the rewards will speak for themselves.