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HPS to LED?

Snook

Still Learning
I've decided to downsize my OP, not that it was BIG to begin with. 4 plants to 2 and going to try LED again.

My question is,:can I transition form a 1K HPS to a 400 watt LED in the middle of bloom (as long as leaf temps are kept in line) without stressing them to hermi?
 

draztik

Well-known member
Veteran
I've decided to downsize my OP, not that it was BIG to begin with. 4 plants to 2 and going to try LED again.

My question is,:can I transition form a 1K HPS to a 400 watt LED in the middle of bloom (as long as leaf temps are kept in line) without stressing them to hermi?

I suggest you do not switch to LED mid flower. If it were me I would finish this run with the HPS and start with LED next run. You won't be happy with the results by switching to LED mid flower.
 

Tangwena

Well-known member
Veteran
I used to use CMH then switched LED quantum boards which I still use because they are cheaper to run.
I did notice an increase in resin with the LED's but it came with a reduction in Psychoactivity compared to the CMH.
But not enough to make me switch back but its there.
 

HempKat

Just A Simple Old Dirt Farmer
Veteran
I suggest you do not switch to LED mid flower. If it were me I would finish this run with the HPS and start with LED next run. You won't be happy with the results by switching to LED mid flower.

I agree with this but only because I'm a big believer in not making any changes during the flower period unless absolutely necessary.
 

Creeperpark

Well-known member
Mentor
Veteran
If you want to learn the answer to that question for your own personal horticulture experience, you have a perfect opportunity with this run. However, if you just want to get the best out of the plants for your jars, then I would finish the run with HPS.

Also, if you are using RO water and not fortifying it with enough Cal Mag, you can experience leaf burn from the switch. Most plants need the extra calcium for stronger cellular protection from LEDs vs HPSs. 😎
 

Snook

Still Learning
I suggest you do not switch to LED mid flower. If it were me I would finish this run with the HPS and start with LED next run. You won't be happy with the results by switching to LED mid flower.

This is my worry about switching (draztic&hempcat). Less psycho activity (Tangwena) doesnt make me happy. More Ca, (Creeperpark) good tip to look out for.

OTOH, cronosyncs' answer 'no problem'.. is what I'd like to experience.. but yes, experience is what it's all about though Creeperpark.
I get the new light 7/19.. I'll do more research and maybe see a couple more member responses. Leaning to screw worrying, just do it. Thanks all.
 

buzzmobile

Well-known member
Veteran
I have a 9 plant grow with a weekly harvest of one plant. I used 1KW MH in veg and 1KW HPS to flower for many years. I watched several growers switch to LED and I jumped in about 3 or 4 years ago with a couple of Fluence Spydrs. Once I added more Cal Mag in veg and early flower things improved. Much less heat than HPS and bud weight increased. I switched mid-flower without any sort of hermie consequence. The 9 plants are spaced one week apart in the flower room. They were in all stages of flower from Week 1 to Week 9.
 

hayday

Well-known member
Veteran
I do perpetual as well and switched with a roomful of plants in various stages.No problems became of this except cooler temperatures. I had to warm the room some
 
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f-e

Well-known member
Mentor
Veteran
Evidence suggests our plants are just photoperiod. The LED will give a more summer-like spectrum, but that doesn't seem to be a flowering trigger. There will be different morphology triggers, but work with the IR you will loose, never seems to amount to anything regarding flowering response. The big change will be heat and how it influences fluid movements. Seen as Calcium issues mainly.

All this aside, I have had plants sensitive to the slightest changes. I would go ahead and change it though, for the knowledge.


No... actually. I changed my mind. It's going to be easier, much easier, to adjust your environment in veg. Where you don't have a ticking clock. I don't know your room well enough to say go ahead now. It's safer in veg, where you can win them back around after correcting any issues. In flower, you just don't have time

I would only change now, if you have major heat issues and a heatwave coming
 

Switcher56

Comfortably numb!
Evidence suggests our plants are just photoperiod. The LED will give a more summer-like spectrum, but that doesn't seem to be a flowering trigger. There will be different morphology triggers, but work with the IR you will loose, never seems to amount to anything regarding flowering response. The big change will be heat and how it influences fluid movements. Seen as Calcium issues mainly.

All this aside, I have had plants sensitive to the slightest changes. I would go ahead and change it though, for the knowledge.


No... actually. I changed my mind. It's going to be easier, much easier, to adjust your environment in veg. Where you don't have a ticking clock. I don't know your room well enough to say go ahead now. It's safer in veg, where you can win them back around after correcting any issues. In flower, you just don't have time

I would only change now, if you have major heat issues and a heatwave coming

That there...
 

exploziv

pure dynamite
Administrator
Veteran
I want to ask for enlightment on that one. How does it work and what can we do to prevent those "ca issues"?
 

abuldur

Member
Changing light during the grow will delay things ,the plant will have to adjust to the brutal change in spectrum and temp.
As for the calcium issue under leds it seems to be a coco related problem.
When i whent back to growing in pure hydro (clay peebles and waterfarms constant irrigation) all problems vanished.
 

f-e

Well-known member
Mentor
Veteran
Like sand in the waves, Calcium movement is almost a side effect of fluid movement within the plant. Fluid movement that is driven by moisture loss. The speed of which is governed by the opening of the stomata, the pores mostly under the leaves. These pores must govern both fluid and air movement.

Under HID's, or the sun, The pores open, to loose moisture, for cooling reasons. Basically the plant sweats.
LED is a cold light. It doesn't cause the stomata to open. Slowing the fluid movement that carries the Calcium around. This also limits co2 intake, but that's just a side note.
Adding fans may not aid fluid loss, as the stomata can just close further as the plant doesn't want to loose moisture because of a draft.
We have to run the room hotter, which helps. Also have more Calcium around, to get swept along.

I'm looking at another idea. Humic Acid. It seems to get moved around by other means, and carries calcium with it. Early days on that learning curve though.


I have no formal training in this area, so much of what I say is open for correction or expanding upon if deemed important
 

f-e

Well-known member
Mentor
Veteran
Changing light during the grow will delay things ,the plant will have to adjust to the brutal change in spectrum and temp.
As for the calcium issue under leds it seems to be a coco related problem.
When i whent back to growing in pure hydro (clay peebles and waterfarms constant irrigation) all problems vanished.
I'm forming a similar opinion. Where substrates high in Calcium are used, some good yields are being seen. Pebbles are a lot of calcium but I'm unsure what a waterfarm is.
 

exploziv

pure dynamite
Administrator
Veteran
Thank you for sharing f-e!
I had and have ca problems under leds. But problem is I have them at 28-29 C as well, so I guess it's maybe from ph or different thing than what you are describing? Or maybe I have too much ventilation and plants protect themselves from drying out by closing stomata? Another reason to leave the laziness aside and mount that PWM control on the ventilation fans.
Thank you again! You sure helped me understand more of this Ca problem.
 

Snook

Still Learning
As usual, there are pros (the yess') and the cons (the nos), thank you all for your input. The LED is coming next week it'll be short of 20 days bloom.. 40+ days to go.. I'd like to go with the yess' but chicken shit me would be very unhappy for any harvest delays or.... seed production by mishap.. think waiting for next run will be prudent.. but in my world anything could change in the blink of an eye (i'd say in a NY minute but so happy I left that state long ago).
 

abuldur

Member
Waterfarms are basic hydroponic units made by general hydro ,water mouvement is driven by air pump.
A combination of various acids(nitric,citric,phosphoric)also seems to help with calcium assimilation.
 

f-e

Well-known member
Mentor
Veteran
In calcium nitrate, the nitrate does some of the carrying work. I heard the roots take in the nitrate, which carries the calcium right to that point. Tap calcium is often made available as the Nitric burns off the carbonate and then the calcium-nitrate is formed. Phosphoric is about half as effective, and it doesn't totally dissolve and go off to do other jobs as effectively. Though this has gains in pH stability. It's not all bad.
 
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