Lighting questions for tomato growing

[tomatodude]

Hope I'm in the right forum. Also this is about tomatoes not marihuana, but that's not extremely relevant.

I want to start growing tomatoes indoors during winter and I'm pretty sure natural light would be insufficient. I'm assuming lighting theory is the same for all plants - in other words the spectrum/wavelengths used, PAR, etc. If not please correct me.

I have read somewhere the following about tomatoes:
200 foot candles - start to photosynthesize
500 foot candles - minimum to support flower and fruit
1000-2000 foot candles - recommended for flower and fruit

I am not 100% positive that is accurate, but wasn't able to find any data like this about tomatoes. If anybody knows for sure or how I could find out for sure, let me know please.

Tomatoes have a light requirement of minimum 8h of light/day, ideally 12+ hours.

A few details about my situation:
1. Electricity cost is high, so I need a low wattage solution
2. I plan to keep doing this every autumn/winter/spring so I prefer a higher investment and lower operating cost than the opposite.
3. I'm confident I can build whatever system I need myself as I am a handy dude.
4. Ideally I want to keep it at or under 100W. Max 200W.

I was thinking to go with CFL initially because is cheap to buy and cheap to operate. Looking at lumen and lumen/watt specs I found it is inefficient compared to ~400W HPS/MH lamps. Also not as efficient as LED projectors in the 30W-100W range (the kind used for stage lighting). So thought that maybe buying something like this would be better:

Proiector cu LED 100W

That's 7200 lumen, 100W. So 72lm/W.

The other idea was to use fluorescent lights placed vertically (several of them) around the plant(s). Maybe in a setup like this (top view):

o......o......o
...+......+
o......o......o

Where 'o' is a fluorescent tube and '+' is the center of the plant. So 2 plants with 6 lights (that would sum my targeted 100-200W) around them vertically. Maybe 2 CFL's on top too. That would provide a design that allows light to reach all leaves of the plants not just the top ones. The tomato plants I will grow get very tall - up to 2 meter. Around the whole thing I would build a DIY growth tent from aluminum foil to reflect light.

Now, there are many light types and probably differ in certain ways. Obviously more is better, but I have the cost (wattage) constraint. So I am trying to find the solution that has a not very high investment cost and low operational cost (ideally 100W, max. 200W).

Also saw this post here:

CFL lumens

The guy talks about PAR and difference between PAR and lumens. Also he talks about a setup he did using LEDs but gives no details about it. He just says it is more efficient. This is my first post so I can't PM him to ask him. If one of you guys could let him know about my post in a PM, I'd appreciate it. I could use his input on this and details about his system.

So hopefully you help me figure out the most efficient lighting solution for my tomatoes.

Also how do you find the PAR of a light bulb? never saw that listed in the specs, not even on manufacturer's site.

Also, does the CRI (color rendering index) matter? From what I understand plants use only a certain range in the spectrum which is rather small. Is that true?

Also, what are your thoughts on LEDs with specific wavelengths that are the ones used by the plants? Is it just fluff and the plant would miss other wavelengths or what?

Thank you very much for your time.

 

[Rald]

You should probably refer to Tomatoville® Gardening Forums

Its strange you'de join a cannabis forum looking to get information on growing 'maters.

 

[small420]

Im sure most here can answer all the questions. I would use what you have planned but put a 250w hps overhead when producing tomatos (flowering). Cost would only be at most 20 bucks a month.(I think)

 

[Hosebomber]

For the first few years of my research in LED lighting I used tomatoes as they are very closely related (in growth rate, properties, and needs) to MMJ. We could use a little more information about the grow area that would help us suggest what lights would be best for you.

How large is your grow area?
What other resources for growing do you have readily available in the room?
What do you not have access to or very little access to?
What kind of venting options do you have?
How many DIFFERENT power circuits do you have access to?

In pure light output visibility (lumens) LEDs are currently the highest lumens per watt at 170+. HPS produces roughly 130 to a max of 150 lumens per watt. The best CFLs produce 70 lumens per watt. Tubes are slightly lower than that.

Plants do not use the human eye (lumens) to grow. While the lumen data does give us some information about how much light is being produced it is irrelevant as a term for plant growth. For that you need the PAR value. You will not find this on 90% of lighting you purchase at the store. Generally speaking you will only find PAR values on grow light bulbs only (and even then most of them do not give you that information). You can extrapolate that information by seeing that the Kelvin color of the light is, but it will not give exact details.

MMJ is a high light plant. Tomatoes are a moderate light plant. You can produce good growth with ~40 watts per square foot of HID. You will need at least 60 watts of CFL and/or tube florescent light to cover the same area. Since this is a MMJ grow site I'll give that information again.

LED = 35+ watts per square foot (of good quality panels)
HPS = 50+ watts per square foot
CFL = 65+ watts per square foot

Length of the room x width of the room gives you the square foot.

If you need more exact information, please be as precise as possible in your grow room details.

 

[buddman52]

leds suck

 

[Hosebomber]

leds suck

I'm guessing you bought a cheap 1/4watt led UFO off ebay that failed to grow for you.
You may want to take a look around any forum in the world and find out that people are growing great quality buds at or above the magic 1 gram per watt rate that the HPS people call you a good grow when you finally reach it. There are a few 1.2 gpw grows (with LEDs) on this forum alone.

Your lack of information and refusal to learn will cause you to fall behind the times in the very near future. LEDs do take different grow methods than CFL or HPS. However, better results can be achieved through LEDs with the current tech.

 

[buddman52]

i did not say you can't grow weed with leds i have magnum+ leds thy were very picey $900 a lamp 3 watt bulbs
just did work for me and i have been growing for 17 years so i do what works for me

 

[Hosebomber]

i did not say you can't grow weed with leds i have magnum+ leds thy were very picey $900 a lamp 3 watt bulbs
just did work for me and i have been growing for 17 years so i do what works for me

That may be your issue. That light is very poor quality 3x1 diodes. While each diode is technically a 3 watt diode it is three 1 watt diodes in a single chip. Likewise, they drive them at less that 40% power. Their listed wavelengths are close to being correct but just enough off to not be very effective. Then there is the ridiculous claim that their 357 watts can replace a 1000 watt HPS. Two of them MIGHT come close to replacing a 1000 watt HPS, IF they corrected their spectra AND they were using actual 3 watt diodes. In their current state I believe it would take at least 3 if not 4 of them to follow through with that claim. By that point you are already using more wattage, spent 15-20 times the cost and are getting close to the heat of a 1000 watt HPS anyway.

While I have no issue with people using HID lighting to grow (I actually use one as well, be it mostly for side by side testing), I do have an issue with people making comments that LEDs suck. 99% of the time that comment is made it is because: 1) They purchased a poor quality light, 2) Believed some bullshit marketing lie about xxx watts replacing a 1000 watt HPS when it's nowhere near realistic, 3) Is a newbie grower that messed up every other aspect of the grow, 4) a HPS only grower that didn't take the time to research or ask questions about how growing with LEDs is different than HID lighting. Nearly all failed LED grows fall into one or more of those areas. Most people wont admit it, however, a 10 minute read through their grow journal will give you all the information to figure out the problems.

 

[mik50]

That may be your issue. That light is very poor quality 3x1 diodes. While each diode is technically a 3 watt diode it is three 1 watt diodes in a single chip. Likewise, they drive them at less that 40% power. Their listed wavelengths are close to being correct but just enough off to not be very effective. Then there is the ridiculous claim that their 357 watts can replace a 1000 watt HPS. Two of them MIGHT come close to replacing a 1000 watt HPS, IF they corrected their spectra AND they were using actual 3 watt diodes. In their current state I believe it would take at least 3 if not 4 of them to follow through with that claim. By that point you are already using more wattage, spent 15-20 times the cost and are getting close to the heat of a 1000 watt HPS anyway.

While I have no issue with people using HID lighting to grow (I actually use one as well, be it mostly for side by side testing), I do have an issue with people making comments that LEDs suck. 99% of the time that comment is made it is because: 1) They purchased a poor quality light, 2) Believed some bullshit marketing lie about xxx watts replacing a 1000 watt HPS when it's nowhere near realistic, 3) Is a newbie grower that messed up every other aspect of the grow, 4) a HPS only grower that didn't take the time to research or ask questions about how growing with LEDs is different than HID lighting. Nearly all failed LED grows fall into one or more of those areas. Most people wont admit it, however, a 10 minute read through their grow journal will give you all the information to figure out the problems.

Can you recommend some quality panels? Advanced? Blackdogs new 5w panels? You seem to know your stuff so thanks in advance.

 

[Hosebomber]

As far as sponsors on this site go, Advance LED is by far the best. There are a few new products out that I haven't been able to test yet though. I've spoken with the people from one of the other companies you mention and they do not seem to grasp the basics of plant growth on a technical level. That's just my personal opinion of course.

A DIY panel is the best option IMHO. If you have the knowledge and ability to make your own panel designed to fit your grow room you will get the best results.