Jump to content

Proper Lighting


Recommended Posts

Quality refers to the actual wavelengths the lights provide to the plants. Light may look white to us, but is in reality made of many different wavelengths as seen in rainbows or when light strikes a prism. It is the red and blue parts that the plant uses for energy and growth, so these need to be provided by indoor lights. Terms you may see for light bulbs that provide these are “natural”, “full spectrum”, or “balanced.” They cost more than the usual incandescent bulbs that mainly provide red light to plants, or the cool white tubes that mainly provide blue light.


I do not know what brands are best or specs. I think you need seperate lighting for growing and buding stages, not just less light.

post-16055-031026900 1281066897_thumb.jpg

Link to comment
Share on other sites

Trying to understand what lighting is best at different stages of growth as well as introducing the change to the plants. Also, would be nice to have a light to plant ratio.



First I would recommend picking up a copy of the book "Marijuana Horticulture: The Indoor/Outdoor Medical Growers Bible" by Jorge Cervantes (note there will be a new edition coming out this year or next). It will become your best friend when it comes to these types of questions.


Typically speaking during veg mode the plants use a bit more of the blue spectrum, and during flower more of the red (around 6500 Kelvin for veg, and around 3000 Kelvin for flower).


As for your request of light to plant ratio, there is no simple answer to that question. It depends on a few factors, what method of growing, what strains, how much height you have to use, stage of the grow, and personal preferences. All things being equal, I guess the easiest answer to your question would be saying that if you figure out how much sqare footage (or square meters) you are trying to cover you can figure out how much light you want as a baseline. Many folks recommend going with 25 + watts per square meter for veg, and 35+ watts per square meter for flowering. I would recommend aiming on the more is better.



Hope that helps a bit.


Edited to add: The only part of flowering (budding) stage that could be considered to need less light would be that you will be going dark for 12 hours a day.

Link to comment
Share on other sites

In my reading, I frequently come across this topic and the general rule of thumb for light to plant ratio is, 60watts per sq foot for optimal (you can produce good medicine with WAY less then that! lol)


But, as was said earlier... There is no right number or simple answer.


Example -


If your grow is a ScroG (Screen of Green) you don't want "sweet spots" of light. A nice even spread of lighting works best.


Your reflector or hood will be a huge impact on how much light you find yourself needing..

Before you buy equipment, research it a little. A hood that is 90-95% reflective and has a nice even light distribution will serve you much better then a lesser product.


Different Light for Different Stages -


Blue light in veg is important. I have seen a few people who use a HPS through Veg and just add in some blue spectrum 300CFLs as side lighting.


For flower, I like to have red and blue spectrum.. seems to produce a more dense bud.


This what I use.


Veg -

first 7-10 days they are under 200w CFLs (5200k)


then for the rest of veg, i use these bulbs


A MH bulb that has also has a good bit of red light.


Flower -






The best hoods I have come across are these -



I can Scrog 4 plants very comfortably under 1 light. Good for a 4x4ft - 5x5ft area, good even light coverage.


Sorry I tend to start rambling after a bit.. :)


The above is just my opinions, different things work for different people!


Best of luck.



Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


  • Create New...