Coco coir grow tent setup questions??

Got a couple of questions regarding my set up ive done some research but there are too many different opinions without the experience so ive come to ask you guys.
Ok here are my questions.

If the temp in the tent is 30 celcius with the door closed and extration fan on is that too hot or should i just leave the door open for now with extraction off?

Are my lights too close? Ive put my hand where the tops of the plants are and it doesnt burn or feel too hot?

Are my seedlings too young for nutes, and should i foliar feed nutes or is will that be a bit too strong and burn them even at the seedling ratio?

400wt hps
Coco coir as medium

Don’t feed them much for a couple weeks, maybe 200ppm of nutes, if you can measure that. Don’t even mess with foliar feeding until you have a few harvests. I never do it, ever, and my plants do fine. Get as much ventilation as you can safely get to keep it cool in there, 30c is pushing it. Your light looks too close in one shot, but it might just be the angle it was shot. Your plants look okay, so far, but I would get that light up as high as you can, if your tent is less than 2.1 meters tall. It looks to be a standard 120cm by 60cm by 150cm tall, or 4’x2’x5’ tent, I would raise it up pretty close to high as it will go.

Do you have a TDS and/or EC meter and pH meter?

Ok thanks for the heads up michael, yes thats the tent just standard, the coir maintains its ph level so im good there but whats tds and ec? Sorry im pretty new to this only my second grow.

I can pretty safely guarantee you, coir does not maintain its ph level. Inside the coir fibres, where your roots can't reach, yes.
But that means bugger all, about the ph your roots are sitting in.
It's all about runoff in coir. It's more important than what ph you feed at.
Ppms too!

It's exactly why Michael suggested a tds (total dissolved salts/solids) meter too. Because your ppms, could be much higher, than you put in. If you're just beginning, you won't have a clue whether the excess is sodium, or just your nutrients, without a tds meter.

Ph, is absolutely essential.
Especially coir.

You can use the pool strips too, to test for sodium chloride.

We go by ec's where I am.
Electrical conductivity, is great to go by too.
For instance. On my truncheon. If my ec on the truncheon, is reading higher than ppms. I know immediately something is up.
I know this because, I know the ppms as well as the ec when I'm mixing, my feed.
Then I just test the runoff.

Here's a good article about the electric conductivity of salt.
I did a little Google for you.
You'll find it handy, I think.

http://www.bbc.co.uk/schools/gcsebitesize/science/add_edexcel/ionic_compounds/ionicanalysisrev1.shtml

Ok thanks i wouldnt have know if you didnt mention that ill checkmit out thanks its only because i read this article and the coir itself said ph stable.

the pH of the medium, when buffered and controlled, remains constant pretty much throughout its useful life. The medium sets its pH at between 5.5 and 6.2, a perfect range, and will hold it there. Unlike peat based products that try to go back to a pH of 4.5 or less within 3 months of being planted.

By using the correct age of coco, with the right porosity, coco potting medium should be able to work through almost a year’s worth of cropping before needing to be changed. The pH stays correct and only the structure changes limiting its useful lifespan.

Buckwheat007 said:

Ok thanks i wouldnt have know if you didnt mention that ill checkmit out thanks its only because i read this article and the coir itself said ph stable.

the pH of the medium, when buffered and controlled, remains constant pretty much throughout its useful life. The medium sets its pH at between 5.5 and 6.2, a perfect range, and will hold it there. Unlike peat based products that try to go back to a pH of 4.5 or less within 3 months of being planted.

By using the correct age of coco, with the right porosity, coco potting medium should be able to work through almost a year’s worth of cropping before needing to be changed. The pH stays correct and only the structure changes limiting its useful lifespan.

Click to expand...

If that's from the CANNA article, it depends on the type of coir. If you use the coco peat, yes. Any other, no.
Any other coco coir buffers itself to ph of 7. Even a tad over.
I grow 100% straight coco. No perlite, or anything.
I don't buffer with lime, or any crap like that either.
Love my coco.

Same here just straight coco its good stuff and i reckon its pretty easy to work with just have to make sure it doesnt dry out!

Buckwheat007 said:

Same here just straight coco its good stuff and i reckon its pretty easy to work with just have to make sure it doesnt dry out!

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You 100% need to pH your water/nutrient solution for coco.
5.8 to 6.2 seems to be the optimal range most folks agree on for coco.
If you do not want to mess with that, use soil.

As far as EC you should be looking around 0.8 or less for the seedlings, once they start pushing out fan leaves you can crank it up pretty fast.

If you don’t start managing your pH soon your plants will be sad. You have a little time, but you cannot neglect it entirely.

It is okay if your coco dries out somewhat between waterings, no real big deal. Too wet can become a big problem, like root problems and/or gnat hell.

I'll sort of agree that the coirs ph does settle in a generally decent range, sometimes with a little help. But the issue is that your plant gets fuck all zip from the coir. It is merely a substrate for your roots to grab hold of. Coir is hydro IMO. That being the case, your juice (both going in and coming out) will tell the tale mi amigo. The coir does need some TLC to remain in that settled PH zone tho.

Grab a meter and you'll learn plenty about what your plant is doing. Good luck!

Potmetal said:

I'll sort of agree that the coirs ph does settle in a generally decent range, sometimes with a little help. But the issue is that your plant gets fuck all zip from the coir. It is merely a substrate for your roots to grab hold of. Coir is hydro IMO. That being the case, your juice (both going in and coming out) will tell the tale mi amigo. The coir does need some TLC to remain in that settled PH zone tho.

Grab a meter and you'll learn plenty about what your plant is doing. Good luck!

Click to expand...

Definitely agreed.
Have to run it, the same as any other dtw garden.

Crazy this fella thinks he doesnt have to ph his water going into coir, going to run into problems real fast

OK OK so I've done some more research you're right I'll grab myself a tester and get to work as I think pH is a bit off and could be having mag def problems nothing major as you can see. But I'll be on top of it first thing tomorrow.

Sorry for the crap camera

Make sure your taking temp readings correctly by placing the thermometer out of direct light just above the light line.
Place something behind your circulation fan to make sure your tent wall is not restricting your fan. It happens with those type of fans.
Then recheck your temps.

Ideally buy a mh bulb.
Your extraction fan should be connected to ducting. One end of the ducting should be leaving the room and preferably the house completely. Otherwise you are recirculating the same air which warms up each pass through the tent.

If I may add my $0.02 here. I had the same setup but with a 600w hps. The heat became a problem. As mentioned 30C is barely ok. I eventually switched from a batwing to a cool tube and it really helped.
I’ll add another vote for ducting out the exhaust. I can’t see a carbon filter so you’ll have to duct it out anyway. I suggest placing the filter on the ground where those boxes are , fan on top of that , and ducting out from one of the top ports to vent the heat as well. You don’t have enough room to keep your filter inside the tent.