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Making the switch from HPS to LED

123 posts in this topic

Hi there @diyleduk


I would like to register my interest in the fantastic competition being run by yourselves. Very generous of you guys. 


I have only very recently just started "My first diary". Where I am covering my experience of growing out some homemade beans.


I do currently flower using hps and CMH, though I expect to see my new Lumatek Zeus 600w pro, supplied by you, arrive very shortly.


If it is OK with you you, I will continue my diary "My first diary" here.

And I will post a link here to each update. 


Please let me know if that's cool or not. 


Thanks :yinyang:

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Hey guys


Here is the link to my most recent update for 28th June 2020 for "My first diary".


Thanks :yinyang:


Hope you enjoy


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Hi there folks.


Just to let you know that I have updated my diary.

There are 2 posts and lots of photos for your viewing pleasure.


1st post Here.

2nd post(pt 2) is right below it so I won't post the link for it here. seems unnecessary to me.


Hope everyone has a great weekend, wherever you are, whatever you get up to.



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Diary update 6th of July 2020



I am documenting my experience of making the switching from HPS 600W and CMH 315W, over to LED(in bloom).


I've flowered under HPS/CMH for a number of years and every year, when summer temperatures start to rise it becomes problematic, dealing with the heat issues caused by having 915W of light in a space approx 1.2m x 1.5m.


I had been following the LED grow light market from a distance for a few years and I felt that now is the time where the technology has reached a performance/reliability/price combination good enough to make me part with my hard earned.


My light of choice is the Lumatek Zeus 600W Pro.


Since Flowering under LED was going to be a new experience for me, I decided the best course of action would be to sign-up to Uk420 for some first hand advice from those already smashing it out of the park.

It was suggested that the best way to get advice would be to start a diary.


I thought that it would be a good idea for me, this run to use some clones of what is already in bloom atm, under HPS/cheap LED combo.

This would give a direct back to back comparison of what, if any differences it makes to the taste/smell/strength or final weight, all while dealing with summer time temps.


I also germinated(3 weeks ago), some more of my own homemade beans as I find it helps, having multiple strains available in the medicine jars.


The seeds, which were created a few of seasons ago in Shumroom's garden when a Sweet Seeds Gorilla Girl hermied causing herself to seed whilst also pollenating an HSO Dedoverde Haze, a Sweet Seeds Cream Caramel and a Blackberry Gum from Seedstockers.

Creating, Gorillaverde Haze and Blackberry Gorilla Gum.


As these pollinations came from a hermaphrodite, I will be keeping an extra vigilant eye on these to make sure that I only keep full female or maybe even a male if I can make sure to keep him separate during bloom.


The Clones were taken from a previous run of my homemade Gorilla Cream Beans.

Mother- Sweet Seeds Gorilla Girl.

Father- Sweet Seeds Cream Caramel.

I initially made 2 selections from multiple plants, one was more Indica leaning finishing at around 8 weeks.

But this selection is a little more on the Sativa side of things and takes about 9 or 10 weeks to finish under HPS/CMH.


These Gorilla Cream clones were potted up into 7.5l airpots 10 or 11 days ago and I think I'll pot on into 20l airpots before blooming them.

I have implemented LST for the first time to see if this can better help me in shaping the plant to achieve a decent yield of well formed colas with the minimum of back breaking work come harvest time.


Here are some photos of how things are coming along so far.


Gorillaverde Haze












Blackberry Gorilla Gum




























Gorilla Cream













I do hope you will join me on my journey of discovery.

See the Lumetek Zeus 600W Pro from @diyleduk in action, along with my own genetic creations.


Thank you for taking the time to read my ramblings :)

I'll be updating this diary again in a couple of days.

See you soon.

Shumroom out.




Edited by Shumroom
eta, pressed wrong button, I need my eyes tested.
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Update 9th July 2020



As some of you may have noticed from the photos in the previous post, a couple of the seedlings were showing a small amount of leaf damage.


2 possible reasons for this:

1. Heat stress.

2. Overwatering.


A few days ago, I had almost certainly watered a couple of them when they could've waited until the next day. Ooops

The location of the seedlings showing leaf damage was near to the T5 which lights the other/larger plants in the veg/nursery space.

As I knew it may have been one, the other or both factors causing leaf damage.

So I made sure to pay special attention to which needed watered.

I also re-positioned the seedlings further away from the other T5 light unit. Just in case it was the heat from the other light causing heat stress.


Here is how they looked earlier:


Gorillaverde Haze 1



Gorillaverde Haze 2



Blackberry Gorilla Gum 1



Blackberry Gorilla Gum 2



Blackberry Gorilla Gum 3



Blackberry Gorilla Gum 4



Blackberry Gorilla Gum 6



Blackberry Gorilla Gum 7




I'll probably start potting these little ones up in the next few days, as most of them have some roots trying to escape from the bottom of the pots already, I'll pop them out of the little pots for a better look at the developing roots tomorrow and see if they need moved on yet.


I need to check the potting cupboard to see which appropriately sized pots I have 8 offer the next transplant.


The other day I decided I will be trying out a slightly different medium with these 8 plants. I'm gonna make my own soil mix using Biobizz all-mix(fresh bag) approximately 2:1 with coco coir, then topped up with perlite. I picked up a coco fibre brick when I was at the pet shop the other day.




Today I pre-soaked the (9l equivalent) coco fibre brick with 4l of water plus CaMg 1.5ml/l, Fish Mix 1.5ml/l, Root Juice 2ml/l and Ferro Enzyme 1ml/l, 45 minutes later I gave it a good mix up and covered it, until I need it.


I'll need to do a little re-organising in the nursery when I pot these on. The HSO Dedoverde Haze will need to find somewhere else to live for the next few weeks whilst the seedlings develop ready to be flowered.


Thanks for your time, until the next update.


Stay safe.


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Hi dude, it'll be interesting to see how the added coco works out for you, the coco that goes in to the potting mix I buy is pre-treated as Coco has a few known issues if it's not buffered properly IIRC.

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Tag @diyleduk :)


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Update for 13th July 2020



Well what can I say really, wow what a busy long weekend that was.


It kinda started on Thursday morning, when I received the first of multiple(expected), deliveries.

The lovely chap from Parcelforce brought me my Highlight 220 from Grow Lights Australia courtesy of Adam @diyleduk.

Many thanks to you for supplying such high quality grow equipment at competitive prices and for having this


Assembly of the Highlight 220 was pretty simple as long as you know the difference between Black and Red(colours) and the +ve and -ve (signs). And which end of a screwdriver to hold.


After touching the nearest radiator to me(to earth myself, getting rid of any built up static electricity), I placed the PCB onto the heatsink, first of all I just finger tightened the centre set of screws to make sure it was properly aligned. I then tightened up the screws using the screwdriver, making sure not to over tighten them.

I then put the rest of the screws in around the edges of the PCB and tightened.

Next I connected the power supply with dimmer to the PCB and using the Wago connectors included. Simple :)


When I went into the nursery/veg area my plan was to use The Highlight 220 to replace the T5 unit which only has 2 tubes and is currently over my seedlings and HSO Dedoverde Haze mother plant in the nursery/veg space for now.


But then I had a better idea (lightbulb moment),

I would instead replace the cheap Chinese LED currently being used in the flowering space, with the full spectrum goodness including UV of the Highlight 220 :)


So I just took out the tray with the tiny pots on it and checked each pot individually to see if they really needed a drink. Those that did got just plain tap water.


Here they are on 9th July 2020






On Thursday night I removed the cheap(m@rs hydro branded) LED which was in place of the 315W CMH for the summer, from the flowering area and hung the Highlight 220 in it’s place.

Except I hung it much higher up, approx 18 inches away from the plant tops turned up to max power :)

Hopefully I can stay out of the crispy leaves club.


Highlight 220 Photos








This is what's being illuminated by the Highlight 220


















I am quite confident that my first grow under the LUMATEK, will produce substantially more than the current one on the go.

Not just because of the NEW LUMATEK ZEUS 600W PRO, but because after one late night watching the TOOB, I decided to SCHWAZZ the life out of all of my plants that were just in their 1st week of flowering.

I’d never SCHWAZZED before and when doing so, I made the mistake of removing far too many branches which I should have left on the plants, I hadn’t considered the fact that I hadn’t trained the plants in preparation for SCHWAZZZING and that doing this would leave big gaps in my canopy, DOH.



On Friday I removed the T5 with 2 out of 4 working tube locations and hung the Cheap Chinese LED in the nursery/veg area, almost as high as I could get it.

Checked and watered seedlings as before, sometimes I would have to lift the same pot a number of times before deciding if it could go one more day without a drink.

I had to water the Gorilla Cream clone which was one day ahead of being potted of her fellow clones, just plain water and nothing else. First drink since potting up on the 25th of June, 15 days previous.



Saturday and Sunday were similar with regards to watering the seedlings, checking and watering only the ones I didn’t think would survive another 24Hrs without.


On Sunday the other 3 Gorilla Cream clones required their first drink since being potted up into the airpots on the 26th of June, 17 days previous. They were given just plain water nothing else.


Gorilla Cream clones









On Monday when I took the seedlings out of the nursery I had a pretty good idea what I would be spending some time doing today, potting up, into 3 inch pots. But first I needed to sort out my growing medium.


Now this is absolutely not a supersoil recipe.

It’s just what I did to freshen up some of my soil(previously used) and try something new.


I had roughly 20 litres of previously used Biobizz all-mix from my crop before last in a large Flexi tub which I had already added ecothrive Charge

I added roughly 3 litres of worm castings and rubbed it through the old soil to mix in. Like making(smelly) pastry :)

Then I added the previously soaked coco fibre, which was a lot wetter than I would have liked, should’ve squeezed the coco out through a colander to get rid of some more of this liquid and any excess salts, especially Na.

I gave this a thorough mix.

Now my tub of soil is much more wet than I would like so I decided to add about 1 1/2 litres of vermiculite the roughly the same amount of perlite and mixed. Again it still seemed a bit too wet for potting up my precious babies. So I then mixed in the remainder of a bag of Biobizz all-mix, maybe about 10 litres or so which had been lying around for some time and was therefore quite dry.

Now I was happy with the consistency of the medium, even although the ratio of coco is a lot lower than I was intending to use, it is roughly 1:5 coco rather than 1:1 I mentioned previously.

Maybe for the best as I’m not sure about whether it was a great idea to use coco which hadn’t been pre-buffered(like mentioned by exhale in the previous post).

I did not water pots at this time.


If all goes well with the seedlings as they root into these pots, I might get more coco, pre-buffered if I can get it and mix it into the 30 litres or thereabouts of freshly prepped soil I now have and increase the ratio of coco when I pot them up next time into what will probably be their final pots.

They don’t need to be in huge pots for flowering as I will be limited by the amount of space in the bloom-room, in beside the Gorilla Creams.

Also these seedlings will all have to be sexed throughout flowering as not only are they not feminised seeds, they also could end up being hermaphroditic(male and female) just like their father(Sweet Seeds Gorilla Girl) was, so I might not end the grow with as many plants as I begin with, after getting rid of any pollen producing plants.


Here they are potted up






In other big news for me, my other new light, The Lumatek Zeus 600W Pro has arrived and it feels a bit like Christmas/Hanukkah :)

I would like to say a massive thanks to the peeps at DIYLEDUK.

Again a great job on the stealthy packaging.



I decided that, as I now have the Highlight 220 in the bloom-room replacing the cheap Chinese LED, I shall not to change out the lighting in the bloom-room until this current crop is done.

I don't fancy trying to raise the Lumatek Pro above the current flowers.


On Tuesday 14th July after an evening slightly concerned about any remaining sodium(Na) in the coco I decided to flush with 2l of plain water to try to limit any problems caused by my lack. of experience with coco and the art of it's preparation.

Now they are in the nursery under the cheap Chinese LED until I can get my QX board which should be here soon, sorted out. I still need to get a driver for the QX board and some wiring and Wagos for it.


Thats it for this mammoth entry.

Thanks for taking the time to read and remember to click follow or give me a comment so I know your there :)

It's nice to know your not writing to yourself.




I'll update again in the next couple of days.

Edited by Shumroom
eta photos, clicked wrong button again :)
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Photos added ;)

Edited by Shumroom

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Nice mate that's some gear you've got now, let's see what you can do with it!

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10 minutes ago, Exhale said:

Nice mate that's some gear you've got now, let's see what you can do with it!

Cheers mate, I hope to do it justice.


I'm currently looking at some underfloor heating for the colder months.


Thinking I might get a 150W 2m² underfloor heating kit and pairing it up with an inkbird digital temp controller to switch it on/off, to maintain a decent root temperature. As it can get pretty cold round my way in the winter months.


And my(scratched) qx board has arrived. 

Many thanks @diyleduk. Such minor marking on it. Great bargain for me :)



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Having heated floor makes such a difference come winter. I made my own bodge version using a reptile heat cable and some porcelain tiles so I can imagine a proper kit will be perfect.

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Update for 16th July 2020



Relatively short update today.


First up are some photos from yesterday afternoon just before lights out for the nursery/veg area.


Gorillaverde Haze and Blackberry Gorilla Gum seedlings.




Gorilla Cream clones.






As you can see from the photos, the Gorilla Cream clones are coming along nicely.

Today I gave a litre of plain water to the Gorilla Cream which had been potted up one day before the others.


Just a short while after taking the above photos, I decided to bend the stem of all but the smallest seedling, in order to bring them all to pretty much the same height as the smallest seedling.

I hadn't initially planned on doing any training to these little ones, but we all know about plans :) they sometimes change.

Plus I reckon that this stress is a good way to possibly root out any problem plants early on, if they can't take some high stress training then maybe best they go sooner than later.


Yesterday I rotated the 2 foot 4 tube T5, 90 degrees and placed it nearer to the right hand side, to give more intense coverage into those corners of the nursery/veg area.

The LED(90W I think) (I need to get a plug in watt metre to check things like this) is able to cover more of the space than it had when the T5 was the other way around.

This should give me the best light coverage in this 1.2m x 60cm space. 


24hours later:


Here's how the seedlings looked today, 24 hours after being bent over just above the 2nd node.















As you can see, all of the seedlings which I bent over yesterday have recovered and turned their heads to the light above.

I am starting to think that I may top these plants after all(still to be decided), in order to get more from each plant that makes it to the end of flowering without having to be removed, due to pollen production for example(nanas).


The Gorilla Cream clones





Tomorrow I plan to tie down the main stems into their new position(seedlings) so that they don't try to straighten back up.

Also make up a sugar/yeast bottle for the nursery/veg area to keep the CO2 content topped up.


That's all for now.

Thanks for reading.



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Update for 18th July 2020



True to my word, after lights out in the nursery yesterday, I got out the plant wire and used it to hold the super-cropped branches horizontal and keep the vertical section of stem from being pulled over by the wire holding the branch horizontal by wrapping the wire tight around the top of the pot rather than making holes in them.


Here's how they looked once I'd finished :chains: them.























I've noted that they could be looking a bit healthier than they are, but I'm putting that down to the amount of moisture still in the medium(soil+coco) after their flush the other day plus they might be a touch too close to the light.

I know the temp and humidity are ok because I bought a bluetooth hygrometer to go into the bloom-room, but I decided to use it in the nursery/veg space until the Zeus goes in.


I'm not overly concerned just now about them, still plenty of time to grow big and strong.

although I am looking forward to them drying out enough that I can get some fish mix and CaMg into them, plus those roots have to go find the wormy goodness within the medium.


Today I adjusted the upside down pots that the seedlings sit on to maintain the distance from canopy to 30 inches away from the LED light, just to make sure that I don't fry them. Things will be easier once I get a driver for the new QB which I got from DIYLEDUK and I will be able to have the light closer to the plants running on a lower wattage.


I topped all of the seedlings today, just above either the 4th or 5th node depending upon the size of each and the node spacing.

the largest plants topped above 4th node and the smaller ones above the 5th node, just trying to keep the height of each plant roughly the same and increase the yield by training for a canopy rather than a Christmas tree shape.

Then I sprayed them all with water, with some Epsom salts, approx one teaspoon of Epsom salts per lire.

I also sprayed the Gorilla Cream clones with the same solution, it's a mild enough solution not to do them any harm.


I have to say that it's great knowing the temp and humidity without having to enter the grow space.

I don't know how accurate these Air Comfort hygrometers are, but being able to set notifications for high/low temp or humidity so that if you want to intervene by turning one of the lights down to reduce temp or whatever, not to mention the graphs :)



didn't take any photos today, I'll get some tomorrow.


Like I said the other day I would do some more training on the Gorilla Cream clones over this weekend.

I do think they will be ready for it by tomorrow. They are looking in excellent condition and looking like they just wanna explode in growth, I have to adjust the T5 height every day. It sits just an inch or 2 above the plants, they are also heading towards the LED light :)


That's all for now, so until the next episode of "Making the switch from HPS to LED"


Stay safe.


:cheers: for reading.





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Great start to the diary...good luck :yep:


Farmer G 

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