CXB 3590 CB Build

I have no experience on what cobs are easier to install. The 3590s are really easy with the cob holders. As for power tools the only thing used was a cordless drill.

benbud89 said:

I love this thread. Its a shame theres no fastforward button to get to the nug shots! Im planning to build a fixture myself. Trying to get an idea of what COBs are easier to install, since I dont have many power tools around. Good thread!

Click to expand...

I would have to say the Bridgelux vero is more convenient because they have integrated holders, the Cree CXA/CXB require a separate COB holder but with either choice you will need at least a power drill and tap or you can always take it to a local machine shop and get them to do it at a cost of course. The other choice and some people won't recommend it is to attach the cob to heatsink with your thermal paste and use kapton tape to help hold it in place. Last but not least you can use a thermal epoxy but don't expect to remove the COB once it's installed. The last two methods require no power tools.

Noticing some brown spots and browning of the leaf veins on the plants. The fact that its showing on the top of the plants points me towards a calcium Defeciency.

Raised the intensity of the lights to 550w and seen that it got noticeably worse over 24 hours. Today i dimmed it back down to 450 and raised the lights slightly.

What have people noticed when the intensity of the cobs is too much? The plants are mostly healthy just not used to experiencing a Defeciency.

Yes, I have read that about the veros. I am going to buy a power drill. Originally I thought I would need an advanced one to drill in the heat sinks, but it does not seem like it. Is that true? On another note, where did you read about heat sinks? Im having difficulty finding precise information about those, its all data sheets about COBs that people care the most for ! I only have a small room, so I am trying to find the best way to make a light with 6 cobs to shed light on six square feet with 30-40 watt/sq foot

@benbud89 here is a good place to start

https://www.rollitup.org/t/heatsinks-for-diy-led-lamps.851907/

Quick update Day 1 of 12/12 was yesterday. When we checked back from the 6th of august to todays date, the Growth has been crazy good.

Were not 100% happy with the plants as weve had alot of leaves with cholorosis which i can't get under control. We thought it was cal mag, but would love for any body elses opinion on it. Im also thinking maybe too much light? But again these are just guesses at the moment. Theres a couple pictures attached of the damage on the leaves.

bruce786 said:

Noticing some brown spots and browning of the leaf veins on the plants. The fact that its showing on the top of the plants points me towards a calcium Defeciency.

Raised the intensity of the lights to 550w and seen that it got noticeably worse over 24 hours. Today i dimmed it back down to 450 and raised the lights slightly.

What have people noticed when the intensity of the cobs is too much? The plants are mostly healthy just not used to experiencing a Defeciency.

Click to expand...

i think its tricky to interpret how plants respond to over radiation. im rotating plants around in my space which is about 10sqft with over 600 w draw of cxbs and veros. just 3 plants in there. One of em has been been supercropped on nearly every branch, big stretch, buds are within 4-5 inches of 2 x 50w 3590 no problem at all. next plant is squatier under 4 x 80w vero 29, about 14-16 inches space. Its real frosty and foxtailing, third plant under cxb is looking pale where light is brightest but dark green towards edges. There is a 46" t5, 54w uvb covering all three.
All of em flowering strongly. Its my first run with this rig.

I keep hearing about much higher nutritional needs when the radiation is prolonged and intense. I have been feeding, watering much more in this grow.

Coming from an organic soil perspective I chalk it up to "generally hungry" rather than trying to address a specific deficiency. It might show up more in the immobile nutrients because the plant will sacrifice fan leaves to steal the mobile nutrients and move them to the apical meristems that are receiving highest intensity.

So to address it in soil I water in EWC, blackstrap and fish hydrolysate but the real solution would have been for me to cook more nutrient into the soil in the first place. I cannot say how to address it for hydro though.

As long as they get access to sufficient nutrients they will adapt, push right through it and yield great.

larger containers are you friend. min 5 gals. I was using all 7s for a while but 10 and 15s are working for my setup.

For sure. I usually use 5g but this round added a 10g to test

What nutrients are you using, and at what EC? Do your other plants have this problem with the same feeding? What is the pH?

If you put your hand level with the canopy, does it heat up?

One of the most common problems on RIU is feeding too low EC in fear of burning babies (ha). Another common problem is using urea based nutrients like jacks classic under the assumption that "if it's soluble, it's good for hydro". Urea based formulas always lack calcium by design.

Just throwing out pie in the sky guesses here. All I can say definitively is "something's not right".

Nutrients Advanced Sensi A+ B
Cal Mag Self mixed ( Calcium Nitrate, Magnesium Sulphate, iron EDTA)
Ive had them on 950-1000ppm. Ive never had this defeciency in veg. So i do believe its something to do with the LEDs. I.e the plants unable to keep up with the growth.

The canopy is definetly not hot from the cobs.

Thanks for the suggestions.

bruce786 said:

Nutrients Advanced Sensi A+ B
Cal Mag Self mixed ( Calcium Nitrate, Magnesium Sulphate, iron EDTA)
Ive had them on 950-1000ppm. Ive never had this defeciency in veg. So i do believe its something to do with the LEDs. I.e the plants unable to keep up with the growth.

The canopy is definetly not hot from the cobs.

Thanks for the suggestions.

Click to expand...

I get this problem week 3-4 of flower and only when I use led. I believe its cal/mag deficiency, raise the light it will help.

thisusernameisnottaken said:

I get this problem week 3-4 of flower and only when I use led. I believe its cal/mag deficiency, raise the light it will help.

Click to expand...

Hey man, thats when i normally see this defeciency, I can never shake it. Thats why i was so suprised to see it during veg.

bruce786 said:

Hey man, thats when i normally see this defeciency, I can never shake it. Thats why i was so suprised to see it during veg.

Click to expand...

The problem is when you are in week 4 of flower and you dont have green fingers and get this defeciency, there is no time to correct it. Also nitrogen toxicity is another problem i get with leds.

thisusernameisnottaken said:

The problem is when you are in week 4 of flower and you dont have green fingers and get this defeciency, there is no time to correct it. Also nitrogen toxicity is another problem i get with leds.

Click to expand...

Do you grow in soil? Ive never had a N Tox but i will bear that in mind.

bruce786 said:

Do you grow in soil? Ive never had a N Tox but i will bear that in mind.

Click to expand...

Yes but next time I want to try coco my cal/mag nute have to much nitrogen, I think this product just gives me problems. Buy the cal/mag nute without nitrogen 0-0-0 and control the nitrogen with either veg/blom nute.

I can also say that I have slightly increased the amount of magnesium sulfate in my own mix and noticed a significant improvement in leaf color and health.

Unfortunately, there are no forms of calcium for hydro that don't also contain nitrogen. Calcium nitrate is the only viable candidate, and thus the best choice. That being said, adding calcium will only antagonize magnesium uptake so if you already have enough calcium, it's best to avoid adding more. If you do have a magnesium deficiency, it would be better to only add magnesium, or even reduce calcium.