Lighting comparison of seedlings under 3500 COB vs T5HO - light green/dark green

[lunarman]

I have some plants at 12 days. All of them had about 5 days under T5's but then I moved some under my autocobs. All pics below are from the same environment and had the same mega crop based feed and are same strain. I can see that the ones under autocobs are lighter green. Its visible in the pictures too. I also have some other plants that look like they might have spotting from calmag def but my camera phone died so no pictures of those yet. LED light height is 20 inches. T5 was about 5 inches. These pics were taken using the same lighting conditions.

I have not used GL's CalmagPro yet for this grow because I had too much N last grow in flower so I decided to gradually add Calmag to this grow.

Is this pretty much normal and to be expected when using COB LED lights? And the solution is to start using calmag now?

autocob plants

T5 plants

 

[Mizzo81]

My guess would be with more light the plant is also using more energy and if they had the same feed then the cob girls would benefit from a stronger solution most likely will result in faster growth also.

 

[Mizzo81]

Poorly worded lol I’m no English professor but you get the idea I’m going after.

 

[lunarman]

My guess would be with more light the plant is also using more energy and if they had the same feed then the cob girls would benefit from a stronger solution most likely will result in faster growth also.

So you think its low N for the COB plants. I am using a pretty high dose of megacrop. 4 grams per gallon. So for the T5's thats ok, but I would need more for the COBs. Is that why they say to feed more Calmag if using LED lights? is it because of a higher energy grow from brighter lights?

I added GL's CMP to by bucket of feed solution and fed some to all the COB girls. CMP has pretty high N.

 

[Mizzo81]

possibly. If they’re gonna stay in the same arrangement try stronger for the cob girls little more calmag.

 

[mcpd_refugee]

Is the light color temperature the same for both lights?

 

[MesaBoogie]

I'm pretty new and only on my first grow with cobs, but I think you have the cob to close at 20" for the age of the plant. I'm just looking how the edges of the leaves are starting to curl up. When I see that I always back off the lights. And I agree with what others have said and cal mag. I started at 30" from seed and have slowly brought it down and let the plant grow into it. I am on day 40ish and am now at 18" from the tops.