1st Grow in 15 years - Looking for guidance - Autoflower (Zkittles & SLH) in RDWC

So, I am going to be starting a new RDWC AF grow in the coming weeks. I am waiting to get everything set up before I start. In the mean time I am looking for some nute guidance and general knowledge/advice from those who have used the same system/setup, nutes, and genetics I am planning to tackle.

First, I have grown in the past with phenomenal success but it has been many many years ago and things have changed since those days but it is my hopes that this will be like riding a bike.

I’ll list genetics, set up, and nutrients we plan to go with and would love feed back.

I plan to keep this grow journalized here and ongoing so this could help someone else in the future.

Genetics: Zkilltes (4) & Sup Lemon Haze (4) - Auto’s
4x4x8 Tent
I’ll be using an 8 site CCH20 RDWC System
600w Black Dog Full Spec LED
8000 BTU AC
Dehum - with range on/off switch
CO2 - with Hygrom/PPM reg
2 Rotating Fans
Closed system Can Fan 6" 560CFM capable
Air Pump and Nute depot will be located outside the tent with a 32 gal overflow site.
Have a Combo meter in Nute Depot to monitor PH, TDS, PPM, ED 24/7

I plan to start the seeds under low intensity T5’s and move to big tent once they have root shoots showing.

Will be growing in Rockwool Cubes.

I also plan to use the GH Expert recirc nute chart (until I get back in the grove) and I also plan on adding the following additional things:
Liq Karma - I’ve read that this could cause nute lockout if introduced to the nute solution. Is this true? In the past I’ve used LK during the seedling/cloning cycle and then as a folier spray only.

Are AF’s okay to use folier’s on during the veg cycle? If so, in the past I used a LK & Dia Nec combo.

Plan to keep room temps in the range of 72-78, after seedling 60% RH during veg and 45-50%RH during flower. Water temps I’ll be shooting for 65-68F. I plan to recirc the room and will keep air pump and nute depot outside tent (I think I said this above but if not).

Anything else I need to know? Please feel free to jump in an share. I am shooting for 1.2 g / watt if possible? I am sure I will need all the help I can get since it has been so long since the last run.




Tent size is wrong on original post:

It is 4x8x8

Also, will be using RO water, not sure of start ppm yet.

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Welcome to the community. Sounds like you have a plan.
Do you have a good PH meter like an Apera PH 20 and a good ppm meter?
Do you have a chiller?

If you ever do photos, you might want to consider 4 plants in a 4x8. Eight can be done, they’ll just be a little crowded.

I run rdwc. I have about 36” x 60” and can fill that area easy with just two plants. I’ll be happy to tag you in if you like.

This is two grows ago. 2 plants.


Good luck with everything! :+1:t2::v::sunglasses:

P.S. if you need anybody, just use the @ symbol in front of their name like @Myfriendis410 which is and expert around here.


One other thing you might want to look at is using Jack’s 321 nutrients. Super affordable and easy peasy! Takes all the guess work out of things. A lot of folks are using it here.
Again good luck! :+1:t2::v::sunglasses:


Plan on a chiller and if you want to get the most out of CO2 you will need about triple to quadruple the light you have now FYI.

Might suggest going with photoperiod rather than autos for a bit better control.

8 plants are doable but would suggest running a smaller number like 4 plants.

Jack’s is probably the easiest system I’ve used and very economical. You run full strength start to finish.

Look into getting neoprene collars, net pots don’t really need to be bigger than 4" either FYI.


@Myfriendis410 & @spyonyou I have a chiller, accidentally left that out of the OP and my tent size is 4x8x8 not 4x4.

@Myfriendis410 I know I’ll need more lights as I go forward but the Black Dogs are a bit expensive so I opted to get the 1 for now and see how this goes before dropping more money for the next one. Question: How many watts would you run in a 4x8 tent with 12 plants on RDWC?

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@spyonyou I’ve always used GH in the past and I feel comfortable with them. What would you say is the difference for you that causes you to stick with Jack’s.

In the past I didn’t have as much luck with a 2 part nute program. I’ve already got the GH nutes so I’ll use them but definitely know things have changed and improved over the years so more insight would be great.


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With GH, questions like do I have enough calmag or maybe something else.
With Jacks there is no guessing. It’s a 3 part that you weigh and mix and that’s it, full strength from seed to harvest, and it’s cheaper. A lot of folks have turned to it because it is so cheap and easy.

In hydro, it is recommended to have your plants at least 2’ apart. Some run one tote on a 5’ sq. scrog.

does it have all the things that Dia Nec, Florabloom and all that offer? I don’t mind mixing my nutes as I have done so in the past with good success.

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I have them spaced 24" from center to center. I remember having a 4 in a 4x4 back in the day. Will the 24" c2c work?

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It’s 3 parts.
Part A 3.69 gr/ gal
Part B 2.44 gr/gal
Epson salt 1.2 gr/gal which you can buy at a local store.

It has everything you need. Everybody is amazed at how simple easy and cheap it is.
You really can beat it (matter if opinion).

Probably be ok. Mine are about the same.

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This question is hard to answer as it depends greatly on the type of LED you are using. Top of the line Samsung diodes? 25 to 30 watts per square foot is ample. Lower efficacy LED’s? More like 50 watts per. A better metric is to use PAR: (Photosynthetically Active Radiation) or PPFD: (Photosynthetic Photon Flux Density). These values give a much more objective answer to your question. Your lights should provide you with spherical test data and nominal heights to hit your PAR values. Normally aspirated (no CO2) you want to be around 600 to 800 µmol/joule/m2 and with CO2 you want 1,200 to 1,500.

I’ve done the full GH line in RDWC and it does a nice job. But expensive when you start to add in all of the micro supplements like LKB, Diamond Nectar etc. Jack’s does it all, does it at full strength and in my case the last 5 plants weren’t even flushed but run right up to water only ahead of harvest. I do use GH silica and an intermediate mix of Jack’s during the first three weeks of flower that changes the ratio from 3-2-1 to 2-2-2-1.2 (the last one is a fourth supplement called MKP or Monopotassium Phosphate). This gives the plant a big P, K boost for flower.

I don’t think I’ll be running GH ever again.


@Myfriendis410 @spyonyou either of you know much about Black Dog LED’s or Platinum?

Thinking of getting another light or two after the above post.

Currently I have the 600w Black Dog

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I wouldn’t have a clue. @dbrn32 can probably tell you something about them. He is our light expert.

Probably least amount of light for the money out there. If they aren’t, they definitely have to be close.

Are you looking for a light to do half of the 4x8?


Thanks db! :v::sunglasses:

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Should I send the Black Dog phytomax 2 600w back. If that isn’t a good light they do a great job marketing it and have it priced at the top of the spectrum.

Chilled tech sent handful of lights to independent light testing facility a few years back, and phytomax 1000 was one 9f them. The test sheets from facility are posted on their website with credentials, I would go look. The report lists less light than hlg-600r and the hlg-600 is about a third of the price. Even cheaper than phytomax 600.

In short, you can get more light for a lot less money. If you can return, I would. Then look at hlg, chilled tech, fluence or something along those lines. Even some of the fluence rip offs like gavita are a lot better value.