Plants get lanky when I switch to HID from T5 in Veg

ButterflyEffect · Nov 17, 2020

My girls are under an 8 bulb T5 HO until the final week or so, then they go around a 315. I make the switch to get them prepared for flower since I run vertical rooms.

My problem is I lose all of the great node stacking that I had prior. The branching is very leggy and the spacing is very tall. I also noticed that on a few of them I had yellowing on lower fans that seemed like Mg. Could be N, I'm not the best with deficiency detection yet. The ones that did were Cinderalla XXX and Cheese.

I'm in hempys and I feed with Jacks 321 @ 1.5 EC. pH 5.8

Also, the bulb is a Phillips 942.

Thanks in advance!

Creeperpark · Nov 17, 2020

If they are leggy its because they need more light. If you are using an old bulb you should get a new one and that will fix it. If you are using a complete fertilizer, then you shouldn't have a deficiency. If you can use pure water it would be best. RO or rain, water fortified with cal-mag before you add nutrients. Post a photo

ButterflyEffect · Nov 17, 2020

Creeperpark said:
If they are leggy its because they need more light. If you are using an old bulb you should get a new one and that will fix it. If you are using a complete fertilizer, then you shouldn't have a deficiency. If you can use pure water it would be best. RO or rain, water fortified with cal-mag before you add nutrients. Post a photo

Thanks for the reply. Very appreciated.

It's a newish bulb and doesn't get much use. It's putting out significantly more light than the T5s that they were under, so I'm not thinking it's a lack of light.

I was wondering if the sharp increase in light intensity created a need that wasn't being met. They balance out once they get into flower and get through stretch. Just this small period of time.

I use rain water exclusively and the Jacks is the hydro formula which increases Mg, i believe, to compensate for RO or rain water.

I didn't get a pic of them when they were ion veg, but I'll grab one and see if I can't get one that'sd representative of what's going on.

Again, thank you very much!

RockinRobot · Nov 17, 2020

Well by my estimate 8 T5HO = 8 x 54w = 432W and you dropped to 315W CMH. Need more light.

ButterflyEffect · Nov 19, 2020

RockinRobot said:
Well by my estimate 8 T5HO = 8 x 54w = 432W and you dropped to 315W CMH. Need more light.

The 315 is vertical while the T5s are horizontal. I've been running vertical for about 5 years now and how the light is dispersed is much more powerful in a 360 degree bare bulb configuration as opposed to the T5s with a reflector. In fact, I can only keep them around the 315 for 10-14 days due to the growth rate. That's why I was wondering if they were deficient in something due to the increase in intensity.

RockinRobot · Nov 19, 2020

ButterflyEffect said:
The 315 is vertical while the T5s are horizontal. I've been running vertical for about 5 years now and how the light is dispersed is much more powerful in a 360 degree bare bulb configuration as opposed to the T5s with a reflector. In fact, I can only keep them around the 315 for 10-14 days due to the growth rate. That's why I was wondering if they were deficient in something due to the increase in intensity.

Even so the T5's are actually more efficient than the CMH. They give off more light and less heat for the same wattage. CMH has better overall spectrum but not the most efficient bulbs.

ButterflyEffect · Nov 19, 2020

RockinRobot said:
Even so the T5's are actually more efficient than the CMH. They give off more light and less heat for the same wattage. CMH has better overall spectrum but not the most efficient bulbs.

Agreed. I do like the effect the T5s have on the plants, it's just the lack of penetration that bugs me a bit. I primarily place them around the 315 to prepare them for flower where they're placed around 2 stacked 315s.

I run 315s due to the spectrum and low heat. I just don't have the electrical headroom for more AC at this point. I chose vertical due to a lack of height and overall room square footage. I could've made it work horizontally, but I run perpetually with 3 flower rooms.

Thanks for the help!

RockinRobot · Nov 19, 2020

ButterflyEffect said:
Agreed. I do like the effect the T5s have on the plants, it's just the lack of penetration that bugs me a bit. I primarily place them around the 315 to prepare them for flower where they're placed around 2 stacked 315s.

I run 315s due to the spectrum and low heat. I just don't have the electrical headroom for more AC at this point. I chose vertical due to a lack of height and overall room square footage. I could've made it work horizontally, but I run perpetually with 3 flower rooms.

Thanks for the help!

Understand the concept of vertical grows and definitely relate to AC cost.

Another cause of your stretch could simply be the spectrum change. CMH is a full spectrum bulb and I'm betting your T5 are veg bulbs with LOTS more blue. The lower amount of Blue could cause stretch.

ButterflyEffect · Nov 19, 2020

RockinRobot said:
Understand the concept of vertical grows and definitely relate to AC cost.

Another cause of your stretch could simply be the spectrum change. CMH is a full spectrum bulb and I'm betting your T5 are veg bulbs with LOTS more blue. The lower amount of Blue could cause stretch.

That's a really good point. The T5s are 5K, iirc. The 315 is a 942(4200k).

I'm curious if there's something I can do to keep it at bay. It negates all of the node stacking from the T5s. Of course, once I get into flower things balance out.

RockinRobot · Nov 19, 2020

ButterflyEffect said:
That's a really good point. The T5s are 5K, iirc. The 315 is a 942(4200k).

I'm curious if there's something I can do to keep it at bay. It negates all of the node stacking from the T5s. Of course, once I get into flower things balance out.

I run 6500k bulbs in veg so 5000k not as bad but definitely more blue than the CMH. I wouldn't worry too much as they're gonna stretch when you flip anyway.

Rembetis · Nov 19, 2020

Hey man, I think you are on the right track with a nute deficiency. The intensity of the CMH is more so photosynthesis is going to kick it up a gear. They will use up N and K too. Lower fans going yellow is a good sign that N is low.

Are you getting floppy stems?

ButterflyEffect · Nov 19, 2020

RockinRobot said:
I run 6500k bulbs in veg so 5000k not as bad but definitely more blue than the CMH. I wouldn't worry too much as they're gonna stretch when you flip anyway.

Thanks. I'm trying to dial things in and this is one of several points of contention that I'm trying to work out.

ButterflyEffect · Nov 19, 2020

Rembetis said:
Hey man, I think you are on the right track with a nute deficiency. The intensity of the CMH is more so photosynthesis is going to kick it up a gear. They will use up N and K too. Lower fans going yellow is a good sign that N is low.

Are you getting floppy stems?

I am. Growth rate seems to be about double from under the flouros. It just spreads those nodes so far apart, too.

I'm at 1.5EC. Maybe go to 2.0? I'm starting to hit them with Ca from 12/12, as I know they like more from then to mid-flower, but it could just be they're hungry.

Rembetis · Nov 19, 2020

If I remember correctly the floppy stems are from low K. It tends to drop off under those conditions.

ButterflyEffect · Nov 20, 2020

Rembetis said:
If I remember correctly the floppy stems are from low K. It tends to drop off under those conditions.

Correct from what I've learned. I'm going with them having a case of the munchies.

Thanks for the direction. On to the next

f-e · Nov 20, 2020

I have always found a plants frame and leaf stems elongate when switching to HID's. I think if you overlay a graph of each lamps output, the HID's obvious heat will show up as more output above 660nm. People in labs have found that energy at this end of the spectrum is responsible for this area of plant morphology.

I use this now. Under LED's I add incandescent lighting if I need to see some stretch. This is certainly more light causing stretch rather than less, but it's not the lumen count that matters, or even the umol/J measures. It's the extra 'out of band' illumination at the far reaches of red and into infrared. Observation offers most of the evidence but some specific reasons have been found. It's real.

Have you also noticed that without the extra red radiation your plants don't show so pronounced leads. No Christmas tree looking plants where the main head or heads are ahead of the rest. The branches don't arrange themselves like a tiered society. The stretch and lead responses governed by the far red spectrum are muted. The plants grow more like round bushes than tall tree's. Outdoor plants are taller more traditional shapes. HID plants stretch. All 3 shapes governed by the far red end of the spectrum. Perhaps with some relationship to the blue present

In my early days I thought it the blue regulating this. Indeed it's a well known tale. Comparisons between Mercury and Sodium growth patterns seem to confirm it. I think the truth is Sodium is a heater with a wide red range but the Mercury (or more recently MH) is more like bands of light. I would have to overlay them to examine this idea but I tend to look forwards and just don't have the time or need to further support these thoughts. I just settle on the red stretching and know it's true as I have used it as a mechanism to fill a few gaps. Causing a sea of green to grow pronounced leads.

To me, what you're seeing is normal.

ButterflyEffect · Nov 21, 2020

f-e said:
I have always found a plants frame and leaf stems elongate when switching to HID's. I think if you overlay a graph of each lamps output, the HID's obvious heat will show up as more output above 660nm. People in labs have found that energy at this end of the spectrum is responsible for this area of plant morphology.

I use this now. Under LED's I add incandescent lighting if I need to see some stretch. This is certainly more light causing stretch rather than less, but it's not the lumen count that matters, or even the umol/J measures. It's the extra 'out of band' illumination at the far reaches of red and into infrared. Observation offers most of the evidence but some specific reasons have been found. It's real.

Have you also noticed that without the extra red radiation your plants don't show so pronounced leads. No Christmas tree looking plants where the main head or heads are ahead of the rest. The branches don't arrange themselves like a tiered society. The stretch and lead responses governed by the far red spectrum are muted. The plants grow more like round bushes than tall tree's. Outdoor plants are taller more traditional shapes. HID plants stretch. All 3 shapes governed by the far red end of the spectrum. Perhaps with some relationship to the blue present

In my early days I thought it the blue regulating this. Indeed it's a well known tale. Comparisons between Mercury and Sodium growth patterns seem to confirm it. I think the truth is Sodium is a heater with a wide red range but the Mercury (or more recently MH) is more like bands of light. I would have to overlay them to examine this idea but I tend to look forwards and just don't have the time or need to further support these thoughts. I just settle on the red stretching and know it's true as I have used it as a mechanism to fill a few gaps. Causing a sea of green to grow pronounced leads.

To me, what you're seeing is normal.

Thanks for this. I could've sworn I read something here regarding what you're explaining. I guess it could be worse, I could be using an HPS instead of the CMH which at least has less of the far red!

Is there anything nutrient-wise that can be used to mitigate the effect?

noknees · Nov 21, 2020

ButterflyEffect said:
I do like the effect the T5s have on the plants, it's just the lack of penetration that bugs me a bit. I primarily place them around the 315 to prepare them for flower

around the 315? like vertically? if not, how so?

if you're going straight from all horizontal to all vertical, it could just be the sea-change of the orientation of the light.

maybe some mild to moderate top-lighting (horizontal) with a cool spectrum would help? LED strips with dimming? might help during the stretch in flower too.

playing with some strips might be clever anyways (transition from t5 to LED)

sbeanonnamellow · Nov 21, 2020

Under the t5's you can get the lamps right on top of the plants, they don't have much room to grow because the lamps are right there in their face so they stack nodes.

When you switched to the CMH it's assumed that there's more distance from the lamp to the plants now, so they are going to fill that space in and stretch out more. Something to consider. Much love

f-e · Nov 21, 2020

ButterflyEffect said:
Thanks for this. I could've sworn I read something here regarding what you're explaining. I guess it could be worse, I could be using an HPS instead of the CMH which at least has less of the far red!

Is there anything nutrient-wise that can be used to mitigate the effect?

The elongation has ties to K but any efforts here are looking for stunting. I wouldn't chase that goal. Maybe a little more N with it's links to foliage and it's suppression of K.. But I don't believe you would get what you want from it.

Just moving a plant can cause it to morph a bit. Moving one and changing the light is a strong combination. You could offer the plant a side salad with it's dinner but there is no way of making it eat it.

It is us that must adapt, rather than the plant. If the stretch is hitting the roof, then flower them smaller or put them on a lower shelf. Give them the room they will take. Ultimately you may find a plant unsuitable for your methods. I have a project within an 80cm ceiling height at the moment. So I can forget my super silver haze beans. I must use things that only stretch 100-150% and flower them when there is space for them to do so(on the net).

Somewhere down the line you could invest in LED lighting. Everything else has had it's day. Using the same light source for the entire process won't lead to so many surprises. Allowing you to better asses the outcome while still in early veg.

Edit: If you want to try something unheard of, then blue leds below the plants could conceivably alter their perception of what a shift to the red across the plant looks like. You can buy a set of decorative blue led lights in Walmart like places for $10 at this time of year. Then cram the bundle under a single tree to see if it does anything for it. I did this with green before stringing them around my room as night lighting.

Plants get lanky when I switch to HID from T5 in Veg

Well-known member

Well-known member

Well-known member

Active member

Well-known member

Active member

Well-known member

Active member

Well-known member

Active member

Active member

Well-known member

Well-known member

Active member

Well-known member

Well-known member

Well-known member

Member

Well-known member

Well-known member