Nick Hardy's Skunk Works #3 5x5 - Dissertation Grow

[NickHardy]

From Gavita's site on how to convert to LED.
1. expect different temps.
2. monitor vpd closely....

5 Tips for a Seamless Transition from HPS to LED | Gavita – Retail

gavita.com

Notes 2 and 5 tie it together.

I think Gavita knows light? maybe lol. But there are thousands of articles on it.

To save you reading to the final paragraph:

We recommend raising the ambient room temperature to make up for this loss in radiant heat. By raising the temperature, it’s possible to mimic the beneficial warming effect of HPS lighting.

It says “Hey you don’t get that radiant heat off LEDs - raise the room temperature to compensate” Gavita (made by Rizen who I bought my HPS DE and CMH from) seem to think like Shed and I - raise the room temp by other means when using LEDs. Seriously everything I find says that, not your raise leaf temps with PPFD theory.

 

[NickHardy]

Right-O moving on from VPD to something that I can nerd out on for hours.

Lights

So I’m using a Meijiu 1978 1000w. No instructions or guides provided as its pretty much a commercial light. I’ve seen some of their mid range sold but not by them. They’re a manufacturer and do either white label - some well known brands In the LED market are made by them or they do a 20 Unit minimum order where you can customise, anything from the LED types and numbers to the colour of the aluminium.

All my other lights are Mars Hydro bar one no brand light.

I’ve seen quite a lot of their installations. My contact there pings me videos from time to time.

Its very pretty is my dome. The plants are 15” in the corners and 22” in the middle.

The light is currently at this height, a fair bit higher than I’d run a Mars Hydro. That would be down at 8”. So i’m going to do two things.

We’re defoliating tomorrow, when we do I’m going to move the corners in to the middle and then raise the light a bit, couple of inches. I want to let the shorter ones catch up a little but also i think the focus of these lights is for a higher hang height, they’re designed for industrial buildings not tents.

Their next watering tomorrow will be on Bloom nutes and we’ll flip them Wednesday. 22” - umm I don’t need no 5ft plants in there - I mean I could make it work. There’s just enough height, I could run the light flush with the roof

Girls are looking solid 7.5s. Neeming daily next few days.

Flip and then home stretch, obvs.



Nick & Co

 

[Absorber]

Right-O moving on from VPD to something that I can nerd out on for hours.

Lights

So I’m using a Meijiu 1978 1000w. No instructions or guides provided as its pretty much a commercial light. I’ve seen some of their mid range sold but not by them. They’re a manufacturer and do either white label - some well known brands In the LED market are made by them or they do a 20 Unit minimum order where you can customise, anything from the LED types and numbers to the colour of the aluminium.

All my other lights are Mars Hydro bar one no brand light.

I’ve seen quite a lot of their installations. My contact there pings me videos from time to time.

Its very pretty is my dome. The plants are 15” in the corners and 22” in the middle.

The light is currently at this height, a fair bit higher than I’d run a Mars Hydro. That would be down at 8”. So i’m going to do two things.

We’re defoliating tomorrow, when we do I’m going to move the corners in to the middle and then raise the light a bit, couple of inches. I want to let the shorter ones catch up a little but also i think the focus of these lights is for a higher hang height, they’re designed for industrial buildings not tents.

Their next watering tomorrow will be on Bloom nutes and we’ll flip them Wednesday. 22” - umm I don’t need no 5ft plants in there - I mean I could make it work. There’s just enough height, I could run the light flush with the roof

Girls are looking solid 7.5s. Neeming daily next few days.

Flip and then home stretch, obvs.



Nick & Co

Looking good mate nice and happy

 

[Jon]

Whoa Gee! That was a lot of work to help someone with absolutely no environmental controls other than an oil heater in the room (otherwise it would be a daytime high of 64º in there!).

I'm not aiming to hit any VPD numbers as I mentioned at the top of my post. I usually grow outside during the day (really hard to control VPD and leaf temps in the, I dunno, 90s? Sunny side pot temps at 121º), and inside at night, with the temps and RH being whatever they are. These two autos I'm going to veg inside-only (after transplant out of solos) to see if that helps them stay out of flower until they're bigger than my autos used to be (I quit growing autos for that reason).

If I move that light until some theoretical increase in leaf temp (though they don't seem related given the results of my experiment), the leaves would be dead from light (not heat) burn. They didn't like 10" so I backed the light up to 12" again (again with no change in leaf temps).

Other than using a light that puts out heat (like HPS), I don't see LEDs increasing leaf temps with decreasing distance. I'll run this experiment again as they grow, but I would encourage others to run the same drill and see if they get the same results.

Is it possible that were your driver not detached you’d have gotten different results?

 

[NickHardy]

Is it possible that were your driver not detached you’d have gotten different results?

The room would be warmer, that does radiate heat and it would be 10” or 12” above the plant so that’s an example of raising the air temp, same as an oil heater. Its the kind of temp increase that works. The maths for VPD doesn't change, enter the new number or your measuring device will for you.

My drivers are all totally outside of the tent. I wouldn’t actually have minded it in there at times this week. Unseasonably cool.

 

[InTheShed]

Is it possible that were your driver not detached you’d have gotten different results?

What Nick said!

There's zero heat coming off the LEDs so any tent-generated heat is from the driver. I actually bumped the watts last night and raised the light to maintain the PPFD, and the air temp in the tent has gone up about 2 degrees.

 

[NickHardy]

There's zero heat coming off the LEDs

Not quite zero and reds will warm a little, I think Wastei mentioned this over at Jon’s gaff? But effectively bugger all.

I thought about it when I arote the previous. If @Gee64 has his driver on the light and he notes temp increase as he moves his lights closer that may well be the radiant heat source, the driver, driving the leaf temp increase (but also of course the room/tent temp.

 

[InTheShed]

At 10" and 12" my light was at 35watts, so zero heat.

When I raise the wattage the light gets raised as well, so no direct influence from the small amount of heat from the LEDs on leaf temps, other than raising air temp (along with the driver) as you mentioned.

 

[NickHardy]

Stage #1 Pop’em 27th October
Stage #2 Peat to sprout 29th October
Stage #3 Seedling Swicks 2nd November
Stage #4 Veg Pots 14th November
Stage #5 Top 2nd December
Stage #6 Defoliation #1 5th December

Day #39

So we like to defoliate the first time just before flip which will be tomorrow. Second is about 4 weeks out from harvest. Need to find my glasses to change the timer or hope Sparky is coming over to do it for me

I’ll flip but I’m not going to count flower til I see evidence of it which is new for us. Another new for us is our EC. Last fill was down at 1.9 - that’s actually in the manufacturers guideline's. Toppy but less than 2.0. It does state though “Without Co2 Enhancement” though. Last grow I didn’t realise we had RO/SO blend of Bloom (same as was delivered yesterday - the logo is tiny) this is meant for the range 2.0ml - 3.0ml per litre and I was working off 2.5-3.5 which the normal one is. Cost us dear in yield so keeping it way down this time.

Here they are, rearranged a bit, a tad scruffy but sure they’ll perk up in a few hours. Light is raised a bit too. Added a bit more Warm White. They’re at 100% 4200k and about 60% 3500k - I reckon something just under 900 PPFD. The baby Dehumidifier isn’t doing nuffink. We just finished trim on the other grow so bagging up to Grove bags this evening. The bigger Dehuey is going in here post haste.

Nick & Co

 

[InTheShed]

baby Dehumidifier

Oh you were so close: baby deHuey!

 

[NickHardy]

Baby Dehuey

Think that’s what you meant

 

[InTheShed]

Yes thanks, link broke. Fixed now!

 

[Greenvein]

Looking great bro i literally just call it a week now. Flower is a week after flip

 

[NickHardy]

Looking great bro i literally just call it a week now. Flower is a week after flip

Yeah I get you though I had a room full of ten dayers last time, but yeah psychologically it’ll be good for me on letting them roll a little longer at the end!

Fed them Bloom nutes.

Cal Mag
A/B Bloom
Total
Take Root
Mono Silicic

All Dutch Pro ex. the Mono Silicic from Grow Genius @Jon tipped me to it. Expensive $50 in the US, $70 for me for 100ml but gosh its good. Next time put I’m going to look into a substitute @Wastei mentioned and save some money.

EC - 2.1
PPM 1150
Ph 5.8

Watered to run off which was about 10L between 12 3 litre pots. Feels about right. Oh and PPM lol. I reached for the Mono Silicic and the pen was right there. Not done one in months and months. That looks OK to me. High but gas.

Flip tomorrow and then counting down the GVFD (Greenvein Flower Day #1)

Nick & Co

 

[Azimuth]

I start my count when I see obvious pistils across the nodes, not just a few here and there that I have to find with a loop. Usually about 14 days for me. Doing it that way helps me be more patient on the back end and not harvest too early.

 

[NickHardy]

Doing it that way helps me be more patient on the back end and not harvest too early.

Exactly my motivations, Batmuth…

 

[Greenvein]

I start my count when I see obvious pistils across the nodes, not just a few here and there that I have to find with a loop. Usually about 14 days for me. Doing it that way helps me be more patient on the back end and not harvest too early.

That makes sense I'm so relaxed about it I'm just like until the hairs turn.
I call it flower from stretch then will say she's about to flower when she's stretching

Next time put I’m going to look into a substitute @Wastei mentioned and save some money.

I just ran out of Root+ from my nutrient line and so has my supplier. Other shops want £100/L so I checked an its a root enhancer with sillicon..
I plan on replacing with seaweed and potassium bicarbonate which I buffer my water with anyway. Hopefully that does the trick

 

[NickHardy]

This is pure silicic acid, I use a different Take Root product. This is for the trunk/branches - I’m putting 3ml into a 100L tank and after a couple waterings you can hang tea cups off them

 

[Greenvein]

This is pure silicic acid, I use a different Take Root product. This is for the trunk/branches - I’m putting 3ml into a 100L tank and after a couple waterings you can hang tea cups off them

I think it works as pesticide too.. so strengthen cell walls, deter bugs and buffer my water sounds like great stuff

 

[NickHardy]

Stage #1 Pop’em 27th October
Stage #2 Peat to sprout 29th October
Stage #3 Seedling Swicks 2nd November
Stage #4 Veg Pots 14th November
Stage #5 Top 2nd December
Stage #6 Defoliation #1 5th December
Stage #7 Flip 6th December

Day #40

So I adjusted the light timer earlier so its lights out at 8pm tonight. 12/12 baby. I also had our room sized Dehuey freed up as we bagged the other grow up to Grove Bags this morning. Fits in like it was made for it.

I deliberately placed it under the inline extractor that is piped to the AC - its popping warm dry air into the fan via convection - warm air rises ldo - its a little drier than I would like and perhaps a little warmer, just dialing it in. I’ve also backed the lights off a bit.

Because, some light burn maybe? Def not nutes unless its deficiency. Very vanilla mix of nutes last night 2.0ml per litre on a range of 2.0-3.0ml per. 2.2 EC I’ll leave it another day or two, I could add some more Cal Mag and A/B I guess. 90L in there 45ml of each.

Rule #2 When in doubt wind it all back and watch.

So I’ll watch a while.

Nick & Co