Hello and thanks everyone for this awesome resource. Ive been trying to do my homework but am lacking some understanding. Its more rocket surgery than I expected lol so thanks in advance for your time and help. My plants are blue dream autoflowers and i have 3 in seedling stag about 3 inches tall. Lighting wise I have 3 150 watt full spectrum leds set at 18 inches off each plant. using apps on my phone i measured to top of seedlings and numbers are. PPFD=160 Lux=11215 DLI=22.47. Im running lights 20 hours a day. Do I need to lower lights to raise PPFD or will i burn them up. Also I figure ill need better lights so any suggestions for a light setup under 500$ to grow 3 plants. Also im not growing in a tent do plan to put reflective material around them in short future. Thank again to anyone who can help. Sorry if I seem ignorant because I am.
yes lowering the lights will raise PPFD…it will also increase the heat on the canopy so you will need a fan to circulate .
I like and use the Marshydro line of lights
I have a Mars hydro and qb board with driver and dimmer they are great lights to start with
Go for HLG, Mars, or Spider Farmer. You will want a light built with Samsung LM301 series diodes.
Ok thank you. I was worried about lowering them down and burning them up. Also thank you for the equipment suggestion. im having a hard time understand the LEDs as far as what kind of wattage I need. was just going of ones that had lots of reviews but pretty sure I dont have enough light. Also ive looked at some charts for the suggested amounts of light is it ok to exceed them? one chart said for seedlingsp suggested DLI was 10-15. is it ok to exceed that numner or is that where ill burn them up. ill be sure to keep a fan running
Generally, 200 watts of quality lighting per plant.
Also lighting depends on size of grow space
Ok thank you for pointing out what diodes I need. i have seen several with the samsung diodes and have looked at the spider farmers. would i be better off buying 3 1000w units or 1 3000 watt unit? I do intend to keep them close together.
Any light that claims to be 1,000 or 3,000 watts is fraudulent advertising. There is no such thing as a 3,000 watt LED. They don’t exist. Many of these lights have a purple hue. We call them burples, and they should be avoided. They are all over Amazon, and the companies are known to manipulate their ratings.
Times two on the SF with the Lm301.
I’m using it I my first small tent grow, Mary loves it.
Lost in the Sixties
That is good info to know. TY ill avoid the ones claiming the high wattage. probably just buy direct from the spider farmer place. Ive seen them recommended several times.
The best way to make sure you are getting a good light is to insist that the light you are buying is built with Samsung LM301b or LM301h diodes. These are the 2 most recent generations of diodes.
During the seedling & early veg stage one light should be adequate. It of course depends on your lights actual draw power. For seedling and during early veg I use a 64w chilled mini. It is a high quality light and its 64w is plently.
Spider Farmer is producing good lights but when you start comparing them to other mass market lights I think you find they are one of the more expensive $ per watt lights.
You may find this interesting. Lights are ranked on 3 year cost to deliver 750 avg ppfd for 3 years.
looks like you have received lots of replies to answer your questions…the light is THE most important part of your setup…get the best you can
That is a very informative and helpful chart. Now that I have a little better understanding of the lights and what to look for quality wise, I realize that my 500 dollar light budget may not support 3 plants. Im just taking it up as a hobby so dont want to to spend to much. Lot of info to wrap my head around. In many cases the more I read the more confused i get. This chart seems like some good straight forward info. Ive learned a lot by this thread already TY
I think one will …
yes very helpful community. Ive learned more from this thread than i have all week trying to read and understand myself
The size of a light relates to the space it needs to cover and not necessarily the number of plants. For a tent, you look for a light that covers it corner to corner during flower. Something with an minimum average PPFD of 700. With photo period plants you need a little more juice because lights are on only 12 hours. In an open space I think you will want a little more light than compared to an enclosed space. You don’t get the benefit of reflected light. If you match the avg. PPFD and the light’s flower footprint to a light using good components you will be fine and capable of producing quality buds.
Welcome to the community! Theres a lot of great help. My 2 cents are when lowering the lights put your hand at thecanopy height palm facing down if the back of your hand feels warm its too close.