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Need help with my 1st grow - White Widow auto in DWC week 7

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Leo
 Leo
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Hello guys. Forgive my english, it's a 2nd language.

I'm trying a MSNL White Widow Max Auto for my 1st grow in a single bucket DWC. Seed germinated on Nov 23th and the rockwool cube was moved to the bucket on Nov 28th, so now I'm in week 6. Using a Canagrow 200w dual COB, the height is set at 0.7m (manufacturer recommends 1.0 to 0.8 for veg) but it has a dimmer, so I'm using about 60%-70% of the full power to avoid burning the plant.

IMG 0050

My tap water here is considered hard I think (EC 0.140) and I'm using the GH Maxgro Maxbloom powders I purchased. When the plant was still a seedling, i tried giving it a one-quarter strength of the suggested Maxgro feeding chart (EC 0.650) and the result was what I though it was nutrient burn (you can the the bottom leaves are in very bad shape), then cut down on the feed when I saw the damage.

IMG 0048

The thing is, even now in week 6, I can't get past EC 0.240 with this plant and I feel something's very wrong. According to what I've read, I should be getting close to 0.8-1.0 now. The plant is drinking, even if slowly. Last week, I tried to increase to 0.7 and the next day more leaves were burned, this time the new upper leaves. As I said, the backgroudn water is 0.140, so I can add only a tiny quantity of nutes to reach about 0.240, anything more leads to huge PH fluctuations. Just a couple days ago, I gave her 0.270 and set the PH to 5.9. Next day, PH as 6.5 and EC 0.290. Here are a couple more pics:

IMG 0045
IMG 0046
IMG 0047
IMG 0049

I regret not having created a diary here to get help from you guys from the start, that was so stupid.... Now I fear that she won't survive till harvest.

I appreciate any input and tips - let me know if you need more info. Thanks!

EDIT: week 6 and I can't see any preflowers yet, still using veg nutes - seems to be very slow...

 
Posted : January 7, 2020 1:50 am
twisted1, ScottishMac, Canna_Educator_ and 15 people reacted
Macky
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2nd language and you can type better than me, 😉 Welcome to Percys man. 

What EC and pH meters do you use? Seems like something isn't giving you a correct reading here. We will figure it out and get you on the right track. I think it looks like a ph problem, are your meters calibrated? 

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Posted : January 7, 2020 7:23 am
twisted1, ScottishMac, Leo and 15 people reacted
Leo
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@macky

Hey man, what's going on. It's a PH/EC/temp combo from a local brand - Akso AK59. It's not the cheapest but still half the price of a Hana. It's supposed to be precise, so I gave it a shot. I calibrate it every 3 weeks more or less with 4.0/7.0/10.0 PH solutions and 1413 us/cm (microsiemens) EC solution. Last time I calibrated it was 2 weeks ago, so you see the PH is already a little off but close:

https://www.akso.com.br/produto/ph-do-solo/medidor_de_ph_phmetro_e_condutividade_de_bolso_ak59-348

20200107 074932
20200107 075245

 

This gives me readings in us/cm (approx. 140 us/cm for my filtered water - regular water filter that I have at home). Tap water is not recommended for drinking here, so we always use a filter to remove some impurity and chlorine - that's the water I have been using for this grow. Water here seems to be hard, we can notice crusty shower heads every now and then (dark color). RO system is out of question now mostly because of space issues right now.

Back to the meter, there are not many choices around here, but there are few options from Hana available that I could get (Groline, HI9814, HI98131, etc). Let me know if you think I should get one of those.

Right now, I'm quite worried, the plant doesn't look very healthy. According to the Maxiseries charts, it should be eating 1.5 tsp of nutes by gallon, i cannot feed it more than 1 tsp for the whole 5 gallon res (about 240 us/cm in my meter). And still no signs of flower that I can tell, so still using Maxigro only. Perhaps I should have bought the Flora 🙁

One other thing, I noticed my res temps have been high in these past month, averaging 22/23C, but sometimes getting close to 25C, even with all the fans - pretty hot these days. I know the risk for root rot and reduced oxygen, do you think this can also be linked to the issue? Roots look ok though, I guess, no smell or dark color and I have 3 "golf balls" air stones in my res. I don't have a chiller yet. Light cycle is 18/6.

Sorry for writing so much, man, trying to give you details to work with.

 
Posted : January 7, 2020 12:36 pm
twisted1, ScottishMac, Canna_Educator_ and 15 people reacted
Macky
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I like it plenty of info. 

Res temps might be the issue then. If you haven't got a cooler then it can cause issues in warm grow room. Temps of the res should be about 18c. But that pic of the roots is fine, they look healthy so i think that's all good. 

Lets discuss the EC meter.... reading of 1412? that might be 1.4, in which case, will be too much for the plant. You sure it measures EC and not ppm right?

ppm to EC conversion chart

 

 

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Posted : January 7, 2020 1:23 pm
twisted1, ScottishMac, Leo and 15 people reacted
Leo
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Res temps might be the issue then. If you haven't got a cooler then it can cause issues in warm grow room. Temps of the res should be about 18c. But that pic of the roots is fine, they look healthy so i think that's all good. 

I'll look into buying a chiller very soon then. Besides the root rot possibility, you think this could also be interfering with the nutrient uptake?

Lets discuss the EC meter.... reading of 1412? that might be 1.4, in which case, will be too much for the plant. You sure it measures EC and not ppm right?

That reading you see in the pic is me dipping it in the 1413 us/cm calibration solution just to show you it is calibrated. Same for the PH, I was dipping it in the 7.0 calibration solution. The current levels in the res are much lower. Please take a look at some measurements I've taken in the last weeks:

2020 01 07 10 49 24

* "Initial" is the reading when I get to the res in that particular day. "Adj." is the reading after I either top the solution with PH'd water or res change (unfortunately i did not log res changes in this sheet)

So you see, the plant is struggling to get past 0.2 EC in such an advanced stage. I have to tell you, I even thought the light could be the problem - does it look to you it could be stunned by the lights? The upper leaves are not curling up.

And thanks for the help.

 
Posted : January 7, 2020 2:12 pm
twisted1, ScottishMac, Zombie Nation and 9 people reacted
Macky
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Guide to EC

Take a look at this article about EC mate. I think you are giving the ppm reading? It needs to be converted into EC< and if thats the case, your EC is very low and the plant will need feeding

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Posted : January 7, 2020 2:25 pm
twisted1, ScottishMac, Leo and 15 people reacted
Leo
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Just to clarify, on Jan 4th you see I tried to up the EC to 0.7 (715 us/cm in the sheet). I changed the res 12h later because the upper leaves tips were turning brown.

 
Posted : January 7, 2020 2:30 pm
twisted1, ScottishMac, Hart and 15 people reacted
Leo
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@macky

The meter displays in µs/cm, so 250 would be EC 0.2, correct? Assuming of course the meter is working correctly. It really has no option to convert to anything else (like ppm)

 
Posted : January 7, 2020 2:34 pm
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Leo
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It is indeed very low, based on the charts you gave me, the current ppm level in the res is about 125ppm which would be insanely low for this stage, but whenever I try to raise the EC, the leaves tips start turning brown. The brown tips would be burn and that I need to lower EC, correct?

I dunno man, I think I got ahead of myself starting out with DWC, should have tried soil before, it would have been more forgiving probably.

And sorry for so many posts, I can't find an option to edit the existing ones.

EDIT: nevermind, i found the EDIT button

 
Posted : January 7, 2020 2:53 pm
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lol, glad you found the edit button, but don't ever worry about posting too much mate, all good info Smile

I started in DWC, its a great medium. You'll be fine mate once you get this EC thing down. The meter doesn't help. Get an essentials one 😉 

The brown spots can be a number of things. Could be hungry, might be cal mag deficiency, ph fluctuation. Could be the EC is too low, and the food is leaching into the reservoir making the brown spots. It's hard to pinpoint exactly. 

The plant does look hungry....... Lets up the feed for a couple of days and see how we do?

That would explain why she hasn't flowered yet too, might just not be enough food to get it started. 

It's better to up it slowly, 0.2 ec at a time. 

I think what you should do, is up the nuits, 0.25ml per litre of cal/mag, and then use grow food, only to bring the EC up to 0.5, so 500 micromoles for you right? Then, after a couple more days, up it to 0.7. 

As the food is changing there will be changes in the plant. but keep the pH of the res balanced. and monitor the EC of the res to see if it rises or falls, and let us know. I think this is definitely down to needing more food if the EC is only 0.2 

ALso, using distilled or mineral water, instead of tap water, will give the plants less calcium. Using LED lights will make the plant use more of it. So a combination of those two could be the issue too. This is why you need some cal meg in the res too i think 

I think, with a bit of cla mag, and some extra nitrogen, she will start to look much better within a couple of days 

 

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"Keep away from people who try to belittle your ambitions. Small people always do that, but the really great make you feel that you, too, can become great.”
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Posted : January 7, 2020 4:25 pm
Joeladalle, twisted1, ScottishMac and 18 people reacted
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