Homemade Light Grow Test

Homemade Light Test - March 1, 2008

This will be a test of a homemade light I built. Thanks to RagnarRoeck for showing me the LM317 circuitry and helping me immensely during the construction. Also thanks to Ryan at HGL for his help too.

The light is using Cree 7090XR leds - 28 Red, 8 Royal Blue. The one main difference of this light is the ability to adjust the intensity levels of the Red and Blue separately. I'm hoping once I learn the effects of different ratios and intensities, this capability will come in handy for tailoring the plants grow behavior and possibly help with different plant species light requirements. Most importantly, I'm hoping it will be beneficial when switching from vegetative stage to blossom stage. From some of my earlier testing, I think I'm seeing better blossom performance by turning down the blue much lower than in vegetative stage. In the blossom stage, I'm trying to just maintain vegetative heartiness, but limiting growth to a minimum. I feel this could help the plant expend it's energy producing blossoms and fruits, not leaves and stems....we'll see.

 The forum thread start off with an 'Instructable' design idea, but later changes to an LM317 design, so if you are interested in details, skip over the beginning of the topic until it gets into the actual schematic, parts, and part sources with the LM317 design. 




I'll be growing four Sweet Red Cherry Mini Bell peppers in my 2x2 area. Hopefully size-wise I can try to keep four of these going. The plan is to keep them as compact as possible adjusting the light ratios. The machine is DWC. Right now I have a 200PPM mixture of FloraNova Grow, Nitrozime, and Canna Rhizotonic. I will be using FloraNova as it seems to be doing a nice job with the same type of pepper plant under the UFO. Rhizotonic which is supposed to be an early root booster requires a lower EC at the start to work best. I did notice the sprouts grew fine visible root real fast, even before they broke ground. Three of the four sprouts are up. One yesterday, two this morning. The fourth one is just about ready to stand up soon.

The light is 13 inches from the top of the grow box. I have the blues all the way on and the red dimmed way down, but on some. As I've been typing this, the cotolydons have gone nice and horizontal already. I'll have to watch them closely as I don't want any stretch if I can help it.

Other things I want to do with this test include using some other light spectrum ranges. I'll be attempting to build some smaller satellite lights for testing the effects these additional spectrums may have. I have some Cree Orange, Green, Cool White, Warm White, and more Red and Blues. First thing I may start with is trying cool white on one, warm white on another, and maybe some geen or orange on a third.

Homemade Light Test - March 9, 2008

Doing well so far. Each of the four pepper plants is about the same. Two true leaves and working on 3 and four. Internodal length looks good and short so far. Root development is going well.

The plants are at about 9 days since sprout. The pictures were taken yesterday, but I didn't have time to do the post until today.

As far as light settings, the blue is all the way up and the red about half way. I really have no way of knowing exactly what the settings are (I wish I had a quantum meter). I'm just going to have to try things by eye based on the plants looks and behavior. The light is still about 13-14 inches from top of grow box.

The light is still performing well with no problems so far. Staying real cool. I do keep the fan inside the grow chamber running while the light is on. I don't think heat is going to be a problem. The cookie pan seems to be doing the trick.

The name of this light is now the "PanHead"

Homemade Light Test - March 16, 2008

Looking good so far for 16 days since sprout.  They seem to be about as fast as the fastest ones I've grown in the past so far. All four of them seem to be about balanced as well which is good for later on when I try some new spectrums in the blossom stage.

The light settings are still the same. The blues are full on and the reds somewhat turned down. Hard to say how far as I'm eyeballing the resulting 'glow' color. The camera seems to make it look redder than my eyes see it. Anyaway the goal is to try and grow a compact plant and so far so good------------------ I think.

Root-wise doing good here too. Nice white ones and they seem to be better every time I look.

The only change I made was to add just another teaspoon of FloraNova grow three days ago. I started real weak and they looked like they could use a little jolt of grow.

Homemade Light Test - March 23, 2008

So far so good. All the plants are about three inches in height now. Still maintaining even growth amongst the four.

The stalks thickened up a lot this week and the number of leaves nearly tripled. I'm happy to see a great amount of root growth took place also. The roots seem to be where the most growth took place this week.

I may have been a little weak on the nutes starting off, but it's better than too strong. I've upped it some today.

Homemade Light Test - March 30, 2008

As far as stockiness and super thick vegetation, I think I'm getting that so far. The stems are real thick and the roots are great. I do see some elongation and some misshapen leaves. The leaves are really green and healthy looking (no burns, spots, or holes), but I thinking I had possibly an incorrect ratio of some sort. The leaves are large, thick, and heavy. Possibly too much blue, which we've heard from some on the forum that this may cause auxins to change the cell structures some.

At the same time as you'll see from the photos that numerous blossoms have appreared.

I'm not panicking by any means because of the leaf shapes. The stockiness, veg, and root growth in my opinion is great. I'm hoping that this blossom oubreak isn't too soon. I've raised the light a few inches.

Have a look at the photos and feel free to give me some opinions in the forum of what you see.

Homemade Light Test - April 6, 2008

The plants did a lot of growing this week. So much in fact it's getting kind of crowded. Quite a lot of bushiness. I removed some bigger leaves from the bottom of the two front plants but haven't touched the other two yet.

Over the last week I've been slowly cranking down the blue intensity and raising the red. The reds are on full and the blue is down quite a ways. The glow is now mostly reddish. I've noticed quite a few blossoms coming out now. The blossoms are quite good size. I hope it's not too soon to try and get some blossoms to work, but I'll go for it anyway.

I'll soon have the blue all the way down (remember from the design, the blue doesn't go al the way off). I'll also be changing the tank to a bloom formula in a day or two.

Might be early, but I'm to impatient to wait any longer to see if I can get some peppers going. The blossoming seems to be responding to the increase in the red and the decrease of the blue just as I was hoping. The controls of the intensities

I'm also hesitant to show a root shot. - When I lift the cover, the roots shoot out like springs and it's a real pain too get them stuffed back in there. The roots are doing great.

Homemade Light Test - April 12, 2008

The plants reaction to the full red power and decreased blue seemed to be immediate. The buds took off and soon turned white and opened up within a couple days. The flowers are coming out strong now and have been over the last few days.

The good news is the blossoms are large in size which I hope means they have a good chance of becoming peppers. The blossom stems are very large and thick. The flowers themselves are large and none have dropped yet. I can't yet guarantee that a pepper will fruit as they are not that far along (I don't think). When the white flower wilts, the blossom tip will either start growing or the entire blossom will shrivel and fall. We should know something in a few days.

Unless it's total coincidence, the plants seem to react very quickly to the various intensities. If I add a little blue, the bushiness really increases. Some of the older leaves with the curl, etc, might mean I had the blue a little too strong or too close. The leaves are very healthy though. I have not lost a leaf yet on any of these plants. Turning down the blue and upping red really got the blossoms to start flowering. 

These early results are starting to show good canopy penetration. You can see from the photos taken of the top canopy how thick the leaves are. I'm seeing great results with the LEDs spread out on the pan heatsink. All four plants' growth seems to be nicely balanced. I think the spread of the LEDs is the reason for the good light getting into the bottom of the plants.

I know it's only one test, so caution, but I really like having the intensity controls so far and I think intensity controls are becoming mandatory for me. They also add the 'fun playing around with spectrum and ratios' factor to growing which should be listed as one of the best benefits of LEDs.

Homemade Light Test -May 26, 2008

It's been a while since the last update, sorry about that. There hasn't been too much 'breaking' news to report. I did take the plants down from four to two plants. It was way overcrowded with the four plants as they were definitely strangling each other. The two remaining plants have grown much larger and thicker and are doing well vegetatively.

I've cycled the red/blue ratios and have learned (on peppers anyway) that flowering can be triggered by full red and lower blue. You can almost see the growth stop and the budding take over. Just the opposite with full blue and weaker red. The plants will veg and bush up almost immediately. This becomes fun to play with and something that can't be done with conventional lighting to such a degree.

The main issue right now is the fruiting stage. I'm thinking my light doesn't quite have the power to fruit well. I say this because I have the same type plants right next to them with same nutrients and conditions and they are fruiting well. The only difference is the light. The peppers I have fruiting well are under a 100 Watt Superled (see Superled Blossom Test Preview photos from the main page).

Another difference is the blue LEDs used. My homemade light is running XR Royals which seem to be best for vegging in my opinion right now (although I haven't tried XR-E Royal yet). The Superled light is running XR-E Blue. It very well may be possible that XR-E blue may be better for blossoming. I did order some XR-E blues that came in. I plan to change out my XR Royals with XR-E blue to see if I can get a blossoming difference. There seems to be a distinct difference on the plants reaction to Blue versus Royal Blue. Possibly a mixture of both could even be better. I'm going to try some different things before I add more power to my homemade light.

I did manage to get three peppers to fruit so far. Not a good number, but it tells me I'm at least getting a little closer. I'm really curious to see if the XR-E blue will make a difference on my homemade light or if for fruiting performance I'll need more power.  I'm at somewhere between 10-15 watts per square foot. The Procyon and Superled lights are 18-20 or so. 20 watts per square foot may be necessary, which still isn't too bad. This would be 180Watts for a 3' x 3' which is usually supported by 400 watts or so of HID.





 

Homemade Light Test - Concluding Comments

Basically, the light did very well (maybe too well) on the vegetative stage. It had fast vegetative growth, very bushy, and real stocky stems. The roots were fine also.

It came up short on the fruiting. Blossom-wise there were plenty. Blossom size was very large. However, the fruiting was poor as only 10 on the two plants turned to peppers.

It was very interesting to see the plants react to the different ratios of red/blue that I played around with. It did seem to blossom immediately a few times when I would keep the red all the way up and lower the blue. Just the opposite the other way. The vegetative growth seemed to pick up with more blue.

Another thing I noticed was a difference in blossoming with the ratios. The one time I lowered the blue, raised the red, blossoms emerged as noted. Then, once the blossoms started to open, I turned the blue back up. This seemed to start the small amount of fruiting I had with these peppers.

I'm thinking for a future test to replace 4 XR Royals with 4 XRE Blues. Possibly also replacing some reds with some warm whites. I'm hoping the poor fruiting results is not because of sheer wattage. I'd like to experiment with different spectrums as opposed to increasing the watts first. 

As soon as I make these changes, I'll start another test.

Please feel free to make comments on the forum.