First Grow Coming Up, Water temp and nutes in RDWC

hilltopbud

Well-Known Member
Everything is ordered and I'm just waiting on my light, tent and bulkheads to show up for my first grow. I'm not sure what information is needed so I will give you my whole setup. 4x4 tent will be scrogged. 4 12 gallon hdx totes with 1 plant each and outside is a 17 gallon hdx tote for a reservoir. Using 3 1/2" netpots and keeping the water 2" below the bottom of the netpot, I will have 6 gallons of water in the 4 totes and 10 in my reservoir for a total of 34 gallons. Seeds are from JBC Seeds, Rare Dankness Ghost Train Haze #1. Light will be a Timber Redwood VS and an AC Infinity 6" fan with controller and carbon filter. I am going to use the GH Flora series along with the Lucas formula.

The grow will be in a building that has no hvac but it never gets below 50ish in the winter. Yesterday I tested my water, no water heater available. The PH was 7.2 and it was 48 degrees. The EC was .3. So I think my water is good to go, just a bit on the chilly side. I checked the water again today and it was at 50 degrees which is what the temp in the building was. I think that it will be fine once under the light.

When beginning the grow and at res changes....should I buy some type of heater to heat the water up to about 60 degrees before filling up the system? Or will the light heat the water up quickly enough that it won't shock the plants? Or should I just fill it with cold water and not worry about it? In my feeble mind, it will be fine for simply topping off at that temperature, but I'm a bit leery of filling up the whole thing with it unless you tell me otherwise.

Regarding the nutes and the Lucas formula. What EC should I shoot for at the various stages of growth? I have done a ton of reading and it seems like people are all over the place, with some using 400 ppm for the entire grow, and some raising it to 1500 towards the end? I'm thinking that I need to have about 5 different numbers: sprout/seedling, first 2 weeks veg, rest of veg, first part of flower, last part of flower. But I have no idea of what to shoot for during each stage. I understand that I should let the plants talk to me to know when to add more and when to add less. But what would some good ranges be to start with? 0.7 EC or 350ppm(.5 scale) sprout/seedling, 1.0 EC or 500ppm(.5 scale) first 2 weeks veg, 1.2 EC or 600(.5 scale) rest of veg, 1.6 EC or 800(.5 scale) beginning of flower and 2.0 EC or 1000(.5 scale) to end flower? Is that close at all?

Thanks for any tips and tricks. This has been a long time coming and will be up and running within a couple of weeks.
Hilltop
 

Renfro

Well-Known Member
In DWC we want cool water becuase it holds more oxygen. 50 is a bit too low but the air pumps should heat the water pretty easily as compressed air is warmer.

Many growers put their water in a tank and aerate it for a while to get rid of chlorine, this would also allow the water time to warm up a little. Generally DWC growers use a chiller in the system to keep the nutrients from getting too warm.

I tend to go straight to 2.0 EC with my rooted clones. I never have issues with that but if I feed lightly I do get issues.
 

hilltopbud

Well-Known Member
Thanks Renfro. I will probably do something along the lines of filling up a container and letting it sit for 24 hours to get rid of chlorine and allow it warm up a bit and just go with it. If I run into problems, I can adjust as necessary.

And I probably will also start with a 1.5 EC and see how things go.

I should get started in a few weeks. Gotta build the room and get the buckets all drilled/put together this weekend. I am still waiting on my light which is supposed to be here the first week of February. I'll definitely start a grow journal and hope you would take a look once it is up and running. All tips would be welcome from you!
 

ҖҗlegilizeitҗҖ

Well-Known Member
In DWC we want cool water becuase it holds more oxygen. 50 is a bit too low but the air pumps should heat the water pretty easily as compressed air is warmer.

Many growers put their water in a tank and aerate it for a while to get rid of chlorine, this would also allow the water time to warm up a little. Generally DWC growers use a chiller in the system to keep the nutrients from getting too warm.

I tend to go straight to 2.0 EC with my rooted clones. I never have issues with that but if I feed lightly I do get issues.
Wow straight to 2 EC for clones? I felt like I was running high feed to my 5 week veg plants at 1.5 EC lol
 

Renfro

Well-Known Member
Well FWIW I have gone straight to 2.0 EC for over 20 years now. Never any issues just fast growth.
 

Renfro

Well-Known Member
how about a gentleman's bet? let this guy run at 1.5 for babies and in one week there will be a post "why do my seedlings look like this?"
lol I don't know that he could grow healthy plants at any EC or I would take that bet but I would want him running 2.0 EC.
 

MustGro

Well-Known Member
Everything is ordered and I'm just waiting on my light, tent and bulkheads to show up for my first grow. I'm not sure what information is needed so I will give you my whole setup. 4x4 tent will be scrogged. 4 12 gallon hdx totes with 1 plant each and outside is a 17 gallon hdx tote for a reservoir. Using 3 1/2" netpots and keeping the water 2" below the bottom of the netpot, I will have 6 gallons of water in the 4 totes and 10 in my reservoir for a total of 34 gallons. Seeds are from JBC Seeds, Rare Dankness Ghost Train Haze #1. Light will be a Timber Redwood VS and an AC Infinity 6" fan with controller and carbon filter. I am going to use the GH Flora series along with the Lucas formula.

The grow will be in a building that has no hvac but it never gets below 50ish in the winter. Yesterday I tested my water, no water heater available. The PH was 7.2 and it was 48 degrees. The EC was .3. So I think my water is good to go, just a bit on the chilly side. I checked the water again today and it was at 50 degrees which is what the temp in the building was. I think that it will be fine once under the light.

When beginning the grow and at res changes....should I buy some type of heater to heat the water up to about 60 degrees before filling up the system? Or will the light heat the water up quickly enough that it won't shock the plants? Or should I just fill it with cold water and not worry about it? In my feeble mind, it will be fine for simply topping off at that temperature, but I'm a bit leery of filling up the whole thing with it unless you tell me otherwise.

Regarding the nutes and the Lucas formula. What EC should I shoot for at the various stages of growth? I have done a ton of reading and it seems like people are all over the place, with some using 400 ppm for the entire grow, and some raising it to 1500 towards the end? I'm thinking that I need to have about 5 different numbers: sprout/seedling, first 2 weeks veg, rest of veg, first part of flower, last part of flower. But I have no idea of what to shoot for during each stage. I understand that I should let the plants talk to me to know when to add more and when to add less. But what would some good ranges be to start with? 0.7 EC or 350ppm(.5 scale) sprout/seedling, 1.0 EC or 500ppm(.5 scale) first 2 weeks veg, 1.2 EC or 600(.5 scale) rest of veg, 1.6 EC or 800(.5 scale) beginning of flower and 2.0 EC or 1000(.5 scale) to end flower? Is that close at all?

Thanks for any tips and tricks. This has been a long time coming and will be up and running within a couple of weeks.
Hilltop
So here's a link to gen hydro's chart. All the PPM info is there. I run FloraNova as my base and my tap water is 50 PPM. I follow the chart pretty close and don't have troubles. https://gh.growgh.com/docs/Feedcharts/GH_FloraSeries-REC_03216am.pdf
I like reservoir temps 18c (65F) to about 22c (72F). My room drops to 16c (61F) at night and hits 24C (75F) under the lights. I'm always trying to cool the reservoir not heat it and I'm in Canada in winter. At reservoir change you can't put cold water in where warm solution was. Only a few degrees difference is allowed. Big temp differences are bad.
Adjust your PPMs to follow the chart for the week of growth you're in.
Week 1 if seedling is 350-400 PPM
Week 2 is a big jump 1050-1350 PPM.
 

hilltopbud

Well-Known Member
Lots of choices! :) I'll probably error on the side of underfeeding and bumping up. You cats that have been at it a while can look at a plant, tell what it needs and do it....rookies like me look at a plant, say "well shit", take a picture, post it and wait for hopefully a good answer. LMAO It is what it is.... hopefully with all of your help and my pics, I can pull this off.

So one question I had about the GH charts...are those ppm's in the .5 scale or the .7 scale? I never see it on any of them. It would be much simpler to me if they did them in EC. From what my feeble brain can tell in my reading, EC is EC but PPM isn't always PPM since there are different ways of calculating.

I appreciate the conversation
 

rkymtnman

Well-Known Member
Lots of choices! :) I'll probably error on the side of underfeeding and bumping up. You cats that have been at it a while can look at a plant, tell what it needs and do it....rookies like me look at a plant, say "well shit", take a picture, post it and wait for hopefully a good answer. LMAO It is what it is.... hopefully with all of your help and my pics, I can pull this off.

So one question I had about the GH charts...are those ppm's in the .5 scale or the .7 scale? I never see it on any of them. It would be much simpler to me if they did them in EC. From what my feeble brain can tell in my reading, EC is EC but PPM isn't always PPM since there are different ways of calculating.

I appreciate the conversation
so here's an EC chart that i kinda use: it's light on the EC for sure. much easier to fix too little nutes vs too much nutes.
,3 to .5 seedlings
.6 to .8 early veg
1 to 1.2 rest of veg and most of bloom
.6 to .8 last 2 weeks

good luck!
 

ҖҗlegilizeitҗҖ

Well-Known Member
Lots of choices! :) I'll probably error on the side of underfeeding and bumping up. You cats that have been at it a while can look at a plant, tell what it needs and do it....rookies like me look at a plant, say "well shit", take a picture, post it and wait for hopefully a good answer. LMAO It is what it is.... hopefully with all of your help and my pics, I can pull this off.

So one question I had about the GH charts...are those ppm's in the .5 scale or the .7 scale? I never see it on any of them. It would be much simpler to me if they did them in EC. From what my feeble brain can tell in my reading, EC is EC but PPM isn't always PPM since there are different ways of calculating.

I appreciate the conversation
I believe those charts are 700x from GH
Here's a 500x scale chart I think generally works well
Screenshot_20210115-195030_Chrome.jpg
 

MustGro

Well-Known Member
Lots of choices! :) I'll probably error on the side of underfeeding and bumping up. You cats that have been at it a while can look at a plant, tell what it needs and do it....rookies like me look at a plant, say "well shit", take a picture, post it and wait for hopefully a good answer. LMAO It is what it is.... hopefully with all of your help and my pics, I can pull this off.

So one question I had about the GH charts...are those ppm's in the .5 scale or the .7 scale? I never see it on any of them. It would be much simpler to me if they did them in EC. From what my feeble brain can tell in my reading, EC is EC but PPM isn't always PPM since there are different ways of calculating.

I appreciate the conversation
Gh is .5 scale. The only company I know of that uses .7 is Cyco.
Here's a link from GH that has some good info. I didn't see them say they use the .5 scale but it's on their site somewhere. It's where my meter is set.
https://generalhydroponics.com/tds-ec-ppm
 

hilltopbud

Well-Known Member
So when doing a res change, do I fill up the entire system with water, dip a gallon of water out of res, mix nutes in that and pour back in to the res? Is that the best way? Or just pour the nutes into the res? Seems like the gallon of water seems like the best bet.
 

ҖҗlegilizeitҗҖ

Well-Known Member
So when doing a res change, do I fill up the entire system with water, dip a gallon of water out of res, mix nutes in that and pour back in to the res? Is that the best way? Or just pour the nutes into the res? Seems like the gallon of water seems like the best bet.
I mix my nutes in my fresh water in a separate container, then dump into the system.
The idea is to make it impossible for highly concentrated nutes to come into contact with your roots
 
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