DTW coco - first time grow, would love some feedback

Hi Guys,

First up massive thanks for everything I have picked up over the past few months of ready and learning. I love seeing all the different method and ways to get amazing results but sadly this can leave a noob like me swimming in eye ball deep in options. Keen to get some advice as to my progress far... (was posted in the coco sub forum but no replies so moved here as it is a better fit. Could a mod delete my old thread as I could not work out how to do it my self, Thanks)



Ok first up my environment -

1.2x1.2m (4x4) tent in a room that sits at between 15c - 20 (60-70) so I have added a small heater that keeps things at 22-24c (74ish) but struggling to keep my RH below 60%. Working to get a controller so I can drop my night temp a little more than the day. As its now going into winter I have flipped my intakes to the roof to draw cold air over my LED heatsinks and then down to the filter which is on the other side of the tent at under canopy level in the hopes to hold more heat in the tent while still cooling my fixture

For the first 5 - 6 weeks from being given a few cuttings (they did not pass on any information about them at all... sucks) I had them under a 200w 4 cob (citizen CLU-1212 @ 1.4A) with 90degree glass optics but now testing out some Samsung LM561C boards. I have a PAR meter on the way and will update with proper readings as soon as it arrives as can only guess as to what my real usable light is...

my four ladies are in 2gallon smart pots with a later of hydroton top and bottom and 70/30 coco perlite mix between. Two pots are showing good root growth out the side, the other two not so much. Probably should transplanted before flipping but hoping I can keep them in small pots and go for smaller and frequent watering rather than risking the move now....

I drip to runoff 1 hour after lights on and 2 hours before lights out each day with 1.2EC EasyGrow brand nuts (local grow shop house blend that worked really well in my vertical basil window farm so stuck with it.... ) and 1ml per L CalMag that I adjust to PH 5.7

The photos attached are late week 8 and about 3 days after flipping to 12/12

I got into the math of the building the DIY lights and found that the plants are now MUCH bigger than expected as I only wanted to half fill my tent (small personal medical supply only). Up till now things have always looked super lush but the past little while the new growth (close and far from the light) are going a light lime green.

I suspect lock out as have struggled to keep my runoff PH in range (they creep as high as late 6s and very early 7s even with 5.4 input and running to a good amount of waste). I have seen the plants eating a solid 200PPM (500 scale) each feed and was assuming the high ph was due to that so had not yet flushed.... the past few day or two I have seen the input to out put difference slow right down but have not yet swapped to the bloom formula as was planning on after today starting to mix a 50/50 mix of bloom and grow for a week or two and doing a gradual change. Dont know why, seems more fancy i guess.

From my searching my issues look to be Iron or Zinc but can anyone help me confirm this.

If this is my issue should I start with a solid flush using fresh nuts till my input is the same as my output PH and see if correcting the root zone ph first. Trying to avoid rushing into anything drastic.

Also could someone confirm my understanding of 20% to waste means that if I put 1000mL in the top and then get 200ml in my drain bucket and not 20% of the containers that the plant is in volume?

Many thanks in advance for reading my rant, fingers crossed im just a new mum and worried about my sweet little babies for nothing but keen to learn how to get back on track if I need to!

Hello friend! Looks like you know what youre doing, youve done your research and you're set for success..

200ppm seems low based on your plant age so i think it will be good if you start increasing it a little as long as they take it.. but you did mention that you will jump on the bloom nuts so thats good

cob and samsung are great for efficiency however due to lower heat you want your room a little warmer 26-27C during lights on if possible as leaves temp is lower with those white LED. I read an article where leaf temp was 2 degrees lower than hps with the same ambiant temp..

If youre not doing it yet id also add some cal/mag in the mix.. for one reason or another with those LED they seems to intake more of that..

3C difference between days and night is totally fine so dont worry too much about it.. and yes humidity will be a bitch if you dont get a dehumidifier.. I strongly suggest.. I know cost upfront is usually pretty high.. but will provide an additional layer of protection/peace of mind and avoid humidity spike during light out

I dont think you mentionned it but also make sure you have a good airflow I think its a key element in any set up..

Its hard to promote transplant during flower.. I think next time you better transplant wait a week and then flip to allow them time to recover. We all make mistakes and youll just get better over time.. you cant buy experience but at least as newbie we can limit the errors and the impact on our grow.

I dont use coco but soil and I love the samsung board! I really think youll get great results! Good job so far!


EDIT: not sure about your intake/exhaust.. so you intake from the top of your tent and exhaust from the bottom? Is that right? Never really seen that before but given you want more heat I guess it should work..

Thanks Viceman for the feedback, good to get some experience eyes on my setup as I have done a truckload of reading and research to try and setup a nice little system.

My current tent as passive intakes at the top with two 150mm tubes leading to the back of my heat sinks to add some cooling to lights but mainly to try and warm up a little. I have a small PC fan running above and a second below the canopy to keep air moving and recently dropped my filter from the roof down to the floor so it pulls from low down in the room in the hopes to encourage more airflow over my lights to preheat our dropping winter air. Seems to work as my heater comes on less often and my heatsinks are running cooler so seems the 150mm inline fan running at about 40% has the suck to fight the normal rise of heated air. I have the fan dimmed for sound reduction as I am having to do all of this super stealth

I put a dehumifier in the main room yesterday and it has helped bring my RH down a bit but sadly my RCD tripped last night and I lost all power to the whole room during my lights on cycle so still seeing if it is strong enough to pull the room down to 50%. I have a small heater in the tent set at 25 but will bump this up a little more and see how things go

The cobs served me well but after trying the samsung boards it is going to be hard to go back. Faster to build, way more even light and they seem to run much cooler. I have two board in there at the moment but need to get an other two in there as my power supplies arrive. At the moment I am only running 120W in the tent!

I have used cal-mag from the get go at 1ml per L as per bottle max but do you think my growth looks like it could use more? Sucks about the pot size but good chance to get my programming skills to work to set up a small pump timer to do more frequent smaller feeds to keep on top of the small pot size. My current timer only has 1 min increments so was working on an arduino controller that can go down to the second.

I did a flush (2L of run off) with some low 5s nutrient (1.2ec) that has pulled my runoff just down in range (6.5-6.6) but have noticed in the past few days of feedings my input and output EC is about the same as if they are not feeding. Is this due to the flushing or a sign i need to move onto bloom nutes? Should I also have flushed with a low (0.6 ec) solution rather than full strength. Once your at the ph runof you want do you then drop in a fresh flush of full strength nuts right on top or do you wait till the next feed?

Once again many thanks for the tips as it has made me feel a lot more reassured I am in the right direction and excited to see the results !

I dont use coco so I cant really tell.. but my understanding is in soil your feeding the soil and the plant eat from the soil while in coco it feeds directly from water similar to hydro.. so assuming thats correct having runoff the same as your watering makes sense and is probably what you want as well its a proof that you dont have salt built up in your coco! Overall they are looking great! But probably someone else can confirm that

cobbled said:

Up till now things have always looked super lush but the past little while the new growth (close and far from the light) are going a light lime green.

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This is absolutely 100% normal, and not a sign of deficiency. New growth always starts off lighter in color than the older leaves, and then the plant slowly adjusts the amount of chlorophyl it needs to darken it up for good photosynthesis. Your plants look fine.

Wilksey said:

This is absolutely 100% normal, and not a sign of deficiency. New growth always starts off lighter in color than the older leaves, and then the plant slowly adjusts the amount of chlorophyl it needs to darken it up for good photosynthesis. Your plants look fine.

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Thanks Wilksey for being so blunt.... I had wondered if I was worried for nothing but as you may have picked up I have a bit of a habit of overthinking things.... I will do my best to chill but so excited to be well into this adventure and dont want to screw it up on the home stretch.

Viceman, interesting about the point of the balanced input/output being because of a lack of build up. So if I see this difference drop (less output vs input) should I bump up my feed EC?

Could someone confirm if the 20% run off I should be aiming for is:

1) based on the amount of fresh nutes put in vs the amount out the bottom ( 1000mL in with 200ml out )

2) based on the overall volume of my pots ( 7.5L so should aim for 1.5l waste per feed )

many thanks!

cobbled said:

Could someone confirm if the 20% run off I should be aiming for is:

1) based on the amount of fresh nutes put in vs the amount out the bottom ( 1000mL in with 200ml out )

2) based on the overall volume of my pots ( 7.5L so should aim for 1.5l waste per feed )

many thanks!

Click to expand...

It's the amount of water. If you put in 4 liters of water and you get 1 liter of runoff, then you're getting 25% runoff.

When I did DTW coco I always watered until I got runoff because it helps leach the salts out of the medium and prevent a salt build up.

FYI you're plants look pretty good. They're perky and praying which is always good. It does look like you need to bump up your feeding though. The plants look a bit hungry based on the coloration I'm seeing. Perhaps you bump the EC up to 1.3 or 1.4 and increase the calmag from 1ML/gal to 2-3ML/gal. Or just leave the EC as is and bump up the calmag by itself.

The light new growth coloration I'm seeing is typically from not enough Ca but I could be wrong.

Massive thanks for the tips.

I gave them 2-3 feeds with a good extra hit of Cal-Mag as well as finally seeing my run off PH start dropping into the mid 6s. Things have started to look far better and so wanted to show the results of the help as I really appreciate it!


the last lights on starting to look like its bouncing back.


And coming to the end of this lights on cycle looking MUCH darker. Tomorrow I plan to double the lights to get ready for the home run.

I have bumped up my Calmag and will start feeding on a 50/50 mix of grow/bloom for the next week with a raised EC as it seems to be finally forming little buds and has almost been a two weeks from flip or should I just go to 100% bloom formula?

Should I do a big prune and take down most of the large sun leaves? I have been trying to spread my thinning back doing a little every few days but stopped while correcting my issues only to have these ladies really take over!