Slow growth since switching to LED

  • Thread starter Weedgrower
  • Start date
  • Tagged users None
W

Weedgrower

30
18
Hi everyone,

I am having a problem since switching from 2 X 600 HPS to a lumatek zeus 1000w. I'm in a 1.5 X 1.5 X 2.2 (H), 20 liter pots with Coco pebbles 60 40.

I have done over 15 grows under HPS and understand the grow speed to be the same everytime, the only thing I have changed is the light. pH 5.8 every time, I'm currently at 1.6 EC 6 weeks in from seed. I'm feeding Canna a and b currently at 1.6 EC. Aptus boosters and CA mg.

Usually I would have tall plants 1 week into flower by now however I'm still in veg but instead I have much smaller plants than usual and they are all different strains.

I have my light 60cm from the plants on 50% I'm not getting any replays from lumatek customer service. I've looked at the par map for this light but lumatek only has a par map for 100% power so can't be sure if it's the correct umol is being distributed.

I'm 90% sure the difference I've noticed is down to the light. I'm thinking is the light too high\low in vertical height or in power.

And advice would be great so Tia.
 
PXL 20220517 015612807
PXL 20220517 015319240
PXL 20220517 015310214
Mikedin

Mikedin

523
93
Not sure about the issue 1k watt led seems like not enough to me I’m at 3k w which is supposedly equal to 2x 600w HPS over 4’x4’ of grow space using LED (about 500 true watts)

What are the true watts of the light pulling from the wall?

Either way your plants look healthy as hell!
 
growsince79

growsince79

8,574
313
Hi everyone,

I am having a problem since switching from 2 X 600 HPS to a lumatek zeus 1000w. I'm in a 1.5 X 1.5 X 2.2 (H), 20 liter pots with Coco pebbles 60 40.

I have done over 15 grows under HPS and understand the grow speed to be the same everytime, the only thing I have changed is the light. pH 5.8 every time, I'm currently at 1.6 EC 6 weeks in from seed. I'm feeding Canna a and b currently at 1.6 EC. Aptus boosters and CA mg.

Usually I would have tall plants 1 week into flower by now however I'm still in veg but instead I have much smaller plants than usual and they are all different strains.

I have my light 60cm from the plants on 50% I'm not getting any replays from lumatek customer service. I've looked at the par map for this light but lumatek only has a par map for 100% power so can't be sure if it's the correct umol is being distributed.

I'm 90% sure the difference I've noticed is down to the light. I'm thinking is the light too high\low in vertical height or in power.

And advice would be great so Tia.
You went from 1200w to 500w and your plants are growing slower. Makes perfect sense.
 
Heywood

Heywood

592
143
Some of it is just going to be a learning curve and getting it dialed in.
I saw @Aqua Man mention earlier today that LED's are about 30% more intense than HID.
I just tagged him, he'll more than likely pop in with some advice.

I just looked at the specs of that light.. that thing is a beast.

I am in the start of week 5 of flower with my SpiderFarmer SE5000 and at 16" height above the tallest buds at 95% power. (480W)
 
Aqua Man

Aqua Man

Staff
Supporter
25,090
638
Ill go back and finish reading the original post to see what i can but here is part of the issue.

Those LED ARE MAD powerful…. I do see some lights stress so backing them off is your number 1 concern right now no matter what other contributing factors are involved until we get this sorted. But i can assure you that they will never need to run over 80% and likely much lower.

So you probably notice your plants are staying shorter and an increase in the density and overall leaf surface area… this is because of the spectral difference. Your stretch will be reduced but overall bud weight will be higher and the buds much tighter and denser… this is spectral due to the photo morphology. I can get deeper into that later if you like.

Also under LED because of the spectral difference and photo morphology the plants will benefit and id go so far as to say need more Ca, Mg and K. It changes the structure of the plants and therefore slightly the nutrient ratios desired.

You are 100% right its the light. But it’s all beneficial so long as you don't over do it which 99% of new growers and growers switching from HID do. Its just hard to wrap your head around how powerful these lights actually are.

As @Heywood mentioned they put out over 30% + more photons per watt than the most efficient HID on the market today.

What intensity and height are they currently at?
 
Aqua Man

Aqua Man

Staff
Supporter
25,090
638
Not sure about the issue 1k watt led seems like not enough to me I’m at 3k w which is supposedly equal to 2x 600w HPS over 4’x4’ of grow space using LED (about 500 true watts)

What are the true watts of the light pulling from the wall?

Either way your plants look healthy as hell!
Those are equivalent watts his are true watts… much much different
 
Aqua Man

Aqua Man

Staff
Supporter
25,090
638
Looking at the pics back the light off to 75 cm and run 18/6 i bet by the end of tomorrow that light stress is gone cause they dont look to bad and i think your just pushing them a bit hard
 
Aqua Man

Aqua Man

Staff
Supporter
25,090
638
Also light drives transpiration so you may see a need to water more often due to the larger leaf surface area (increasing overall transpiration) and increased transpiration rates
 
W

Weedgrower

30
18
Not sure about the issue 1k watt led seems like not enough to me I’m at 3k w which is supposedly equal to 2x 600w HPS over 4’x4’ of grow space using LED (about 500 true watts)

What are the true watts of the light pulling from the wall?

Either way your plants look healthy as hell!
I was told led has a more intense light. When I look at the umol chart it has a great ppfd map and with 8 bars in its close to 1000 umol over the canopy, so my thinking is a plant in veg needs 300 to 550 umol so following the lumatek chart 50% power would equate to around 500 umol at 56cm. Right?
 
Screenshot 20220322 170859 Office
W

Weedgrower

30
18
Lower the lights and put to 60%
I can only go up in increments of 25%. I had my lights lower and I thought that was the reason for no tall growth, so I highered the light and I feel like they grew quicker
 
W

Weedgrower

30
18
Ill go back and finish reading the original post to see what i can but here is part of the issue.

Those LED ARE MAD powerful…. I do see some lights stress so backing them off is your number 1 concern right now no matter what other contributing factors are involved until we get this sorted. But i can assure you that they will never need to run over 80% and likely much lower.

So you probably notice your plants are staying shorter and an increase in the density and overall leaf surface area… this is because of the spectral difference. Your stretch will be reduced but overall bud weight will be higher and the buds much tighter and denser… this is spectral due to the photo morphology. I can get deeper into that later if you like.

Also under LED because of the spectral difference and photo morphology the plants will benefit and id go so far as to say need more Ca, Mg and K. It changes the structure of the plants and therefore slightly the nutrient ratios desired.

You are 100% right its the light. But it’s all beneficial so long as you don't over do it which 99% of new growers and growers switching from HID do. Its just hard to wrap your head around how powerful these lights actually are.

As @Heywood mentioned they put out over 30% + more photons per watt than the most efficient HID on the market today.

What intensity and height are they currently at?
Ok thanks for the reply, you mentioned that you can see light stress, how would I identify that on my plants?

I'm currently on 50% power 60cm above the canopy. I started the seedlings at 25% and the same height after the seedling stage I upped to 50% and maintained the 55-60cm from the canopy.

After week two I didn't really move the light away and let the plants grow closer for the next week they did 0 vertical growth so I figured moving the light up and then the growth continued up but slowly.

As you can see on the ppfd chart if you remove 2 bars of the light at 100% power you get a very healthy spread of light. So I am on 50% same hanging height knowing my plant can take in up to 550 umol/m2/s in veg I'm hoping that at 50% power will provide around 500 but can't be sure without a umol meter, them things are expensive. I know I can get a par meter and do a conversion to get umol however I don't really want to do that as I'm not convinced of the accuracy.
 
Screenshot 20220322 170859 Office
W

Weedgrower

30
18
Looking at the pics back the light off to 75 cm and run 18/6 i bet by the end of tomorrow that light stress is gone cause they dont look to bad and i think your just pushing them a bit hard
Ok they are currently 18\6 and ye my thinking was if i want them to go up I move the light up so they can stretch to reach it, but I didn't want to do that incase the fact was too little light and therefore would be even more negative impact on them. I'll move them up now.

I managed to speak to a guy for 5 mins from lumatek and he said what people are doing with these lights are... 25% for seedlings 50% for veg, 75% for first half of flower and 100% for the second half of flower with 8 bars in to maximise the fact the plant can take in 1000umol when flowering
 
W

Weedgrower

30
18
Also light drives transpiration so you may see a need to water more often due to the larger leaf surface area (increasing overall transpiration) and increased transpiration rates
What your describing is exactly what I've experienced. Small dense plants with huge leaves, I had to remove quite a few insanly large fan leaves that umberellad the whole plant to allow the light to get to all the nodes
 
F

FriendlyFarmer90

8
3
You might want to look into the digital controller from lumatek. It costs a pretty penny but gives you so much more control over the light. You can change the intensity with 1% increments. I use the 600w pro version of the zeus and since ive had it ive stressed and burnt my plants everytime. These lights are pretty crazy. I recall that for the 1000w they advise the use of co2 also otherwise you cant even run it full blast unless its far away from the canopy which dont make sense either.
 
W

Weedgrower

30
18
You might want to look into the digital controller from lumatek. It costs a pretty penny but gives you so much more control over the light. You can change the intensity with 1% increments. I use the 600w pro version of the zeus and since ive had it ive stressed and burnt my plants everytime. These lights are pretty crazy. I recall that for the 1000w they advise the use of co2 also otherwise you cant even run it full blast unless its far away from the canopy which dont make sense either.
Yeah I didn't even know that controlled existed I'll check it out, yeah it's more like co2 compatable as you can get a ppfd of 1600 umol if you use all 10 bars, I have 8 in and thinking about it that math doesn't add up, I put the 2 bars back in and gain 60% extra ppfd. You only need to introduce co2 if you plan on utilising more than 1000 ppfd which if you look on the bottom pic I can get a great ppfd of 1000 (co2 not necessary) with 8 bars in at 65cm
Screenshot 20220322 170859 Office
 

Similar threads

G
Replies
4
Views
1K
Christos1974
C
C
Replies
8
Views
755
phxazcraig
phxazcraig
BigBlonde
Replies
3
Views
224
BigBlonde
BigBlonde
Kepp89
Replies
1
Views
202
Ponky
Ponky
Top Bottom