First Grow Dwc Problem

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M

Muckworm

31
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Hi. I started from seed on Jan 5th. Germinated in Rockwool. Started in buckets on the 12th. Moved them from (4) T5's to my large grow tent 5x5 on the 26th. The girls are White Widow. They are under a 1000 watt HPS bulb ballast down to 600, then raised to 750 yesterday. I also had my air cooled hood all the way up and have been bringing it down an inch or so daily to get to where I should be heat wise. My problem was humidity. I was running at 19 percent. I've bought 2 humidifiers and now have it pretty stable at 40 percent. The top leaves of two girls are dried at the ends and dying now, but the plants seem to be growing great with beautiful growth under the top leaves. I'm certain I have the ppms and ph just right. Wish I knew how to post picks. The plants have huge, drooping fan leaves. Don't know why. Can low humidity burn and curl the leaves up. Should I cut them off or leave them until they die. Your help is appreciated.
 
Douglas.C

Douglas.C

312
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Nutrient temperature? MUST be between 65F and 69F, I prefer 68F as it gives me a 1F buffer.

Wilting is lack of O2 due to not enough air bubbled in the res and/or root rot.

Ppms are good at 800ppm or less, depending on what you're feeding them. The closer to a correct balance, the less you'll need to support full and vigorous growth.

pH needs to start at 5.4 and rise to 5.8 before adding nutes to drop it back down. Full pH swing cannabis is so much healthier and cleaner than working to maintain a flatline pH range.

Clip the damaged tops off, get the resources to the next lower down nodes as soon as possible. Basically a quick topping and you'll end up with more branches.
 
M

Muckworm

31
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Thank you for your reply. I will do as you said immediately. When you say top them. Is that the same as super crop? My nodes look great. It's the huge fans turning brown and drying out. My bubbles are ripping. ph at 6. Nutes at 500. Actually using RO water so I add cal mag to bring it up to 200. Then nutes as it says brings it to like 350 to 400. I just bumped to 550. I also am using current culture h20 for my nutes. Along with UC roots. My roots are bright white with green roots coming through the pots. No smell. Just added photosynthesis plus. The plants woke up nicely. But I'm still not out of the woods. Hard to control my water temp. I'm trying. It's at 68 now but I've seen it climb to 73. Ugh. This is all cool as it's a learning experience. My bulb is a hortilux blue 1000 watt. Just swapped out my flowering bulb yellowish as I was told. I'll send a pic of my set up. Please keep the suggestions coming.
 
M

Muckworm

31
8
Oh and room temp right now is 68. Humidity 40 percent. I find if I raise the temp above 72 my water temp gets to high. I have each plant in 11 gallons of water and two sets of bubblers screaming in them.
 
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Douglas.C

Douglas.C

312
63
Thank you for your reply. I will do as you said immediately. When you say top them. Is that the same as super crop?
Happy to help. ;)

Topping is cutting the top off, supercropping is crushing the stem and bending over. LST is gently pulling a branch horizontal and tying it off.


My nodes look great. It's the huge fans turning brown and drying out.
Likely a combination of pH issues and possibly starving a bit for nutes. 500ppm is a bit low in high light conditions.

My bubbles are ripping.
Too much air can be a problem. Turn off the pumps for an hour and see if your pH drops. If it does, there's actually too much air going through the solution.


ph at 6. Nutes at 500. Actually using RO water so I add cal mag to bring it up to 200. Then nutes as it says brings it to like 350 to 400. I just bumped to 550. I also am using current culture h20 for my nutes. Along with UC roots.
pH at 6 is too high. Full nutrient uptake happens when pH rises from 5.4 up to 5.8 and then dropped back down to 5.4 using nutrients.

Cal/mag?? The current culture h20 mix you use is low on calcium and nitrogen for cannabis? You checked their nute calculator (hopefully they have one) and are mixing for what cannabis needs, yes? Epsom salts are usually all that's needed for dealing with the magnesium variable. The sulfur in it is good for terpene production as well.

There is zero need to add cal/mag to r/o, simply because it's r/o.

My roots are bright white with green roots coming through the pots. No smell. Just added photosynthesis plus. The plants woke up nicely. But I'm still not out of the woods. Hard to control my water temp. I'm trying. It's at 68 now but I've seen it climb to 73. Ugh. This is all cool as it's a learning experience. My bulb is a hortilux blue 1000 watt. Just swapped out my flowering bulb yellowish as I was told. I'll send a pic of my set up. Please keep the suggestions coming.
Keeping the 68F stable is massive. Even a few hours of high temps will impact yield.

Swapping bulbs won't make much of a difference until everything else is in line, no worries. Drop the pH down to 5.4, bump the nute solution up to 600 and then watch the pH slowly climb. :)
 
Nayhay

Nayhay

12
3
Is the nutrient water level higher than the bottom of the plant baskets? I have found this drowns plants. Keep that water level down and the roots get more oxygen. Back when I did DWC I often had res temps in the 70s and higher. I'd toss in big chunks of ice to help, but didn't have much problem with higher than ideal temps.
 
Douglas.C

Douglas.C

312
63
Is the nutrient water level higher than the bottom of the plant baskets? I have found this drowns plants. Keep that water level down and the roots get more oxygen.
This is good advice. Also, keep the same level of nutrient solution, when you add more than before it will waterlog roots which have adapted to being in air.

Back when I did DWC I often had res temps in the 70s and higher. I'd toss in big chunks of ice to help, but didn't have much problem with higher than ideal temps.
15 years experience says this is not good advice. You may have gotten away with it occasionally, but coaching others that it's not an issue is doing them a great disservice. Whether you were aware of it or not, your grow suffered and you lucked out.

68F max will ensure no issues from temp based root rot. As I stated before, if you cannot keep the reservoir consistently below 69F, look to a medium based grow. They do better at 75F-80F temps without issues.
 
M

Muckworm

31
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Thank you all for your replies it meNs so much to me. I will update tomorrow. Thanks
 
M

Muckworm

31
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Okay so I rotated the plants and did as you all recommended with very good results. Now I have another issue but I'm not sure how big of a deal this is. My 1000 watt bulb continued to slightly burn my leaves even with it all the way up in the tent. The strain is white widow. The plants are not shooting up and are getting bushy. Should this concern me. Will the plants too leaves will be able to handle the heat when I switch to bloom? Currently I just keep the lights on 24/7. Plan on switching to 12/12 in two weeks.
 
M

Muckworm

31
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The reason I'm 24/7 is that I'm trying to control temps throughout the day and night. Not easy when one day it's freezing out and the next it's 58. Ugh.
 
M

Muckworm

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The pics I just added showing burn was from when the lamp was two feet above the plants. I have controlled the burn by raising the light as high as the tent will allow me. Like 3.5 feet.
 
Douglas.C

Douglas.C

312
63
The light should be 18-24" away. Those leaves are not burning from light exposure, it looks more like pH or salts related issues. I'm unfamiliar with the nutes you're using, so I'm not that helpful on whether it's the right mix or not.

The numbers you want to be close to are these 100N-100P-200K-60Mg. These are the numbers Mel Frank posted years ago, the Lucas formula is close to this. Does your nutrient mfg have a nutrient calculation tool?
 
M

Muckworm

31
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Yes and I was right on it until I was told to raise my nutes and drop the PH. You know what's weird is that I have a couple small mothers growing in soil under T5,s and I'm seeing the same type thing on the leaves. At first I thought it was a mag/cal prob. Nope. Than I thought it was low humidity 19 percent. Nope. Now I'm thinking if it's not the light could it be bad seeds? White widow fem. let me send you a pic of the two girls growing in the t5 closet.
 
M

Muckworm

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Oh and my plants are doing much better now. These were older pics. I will send updated ones tonight. It just seems to me if I drop the light the top leave start to show that burn dry look. Wish I could figure out what's going on. I'll post the feeding regiment I'm using as well. Thank you so much.
 
M

Muckworm

31
8
Forgot to mention that my well water was at 340 ppm to start, so I bought a small under the sink RO system thinking my water was bad. I start at 30ppm now. That's when I added cal/mag to 200 (which I won't do anymore) the Veg A, VegB and UC roots as directed. I have always went on the low side as well being careful not to over do it.
 
Douglas.C

Douglas.C

312
63
Oh and my plants are doing much better now.
Tentatively, I'm leaning toward your plants trying to eat themselves at the previous nutrient level. Having not enough nutes will cause deficiency issues as well. As long as they continue to do better, the low nutrient strength was the main issue at hand.

Keep in mind...
When temps are 75F-85F you'll need 30%+ Relative Humidity to prevent issues from over transpiration. Transpiration rates are what keep the nutrient flowing through the plant. When transpiration is not needed for cooling the plant (in high temps) you need low humidity. The low humidity causes transpiration through the attempt to stay hydrated on the outer surface of the plant.

When the temps are high, the plant is using transpiration for evaporative cooling. Having low humidity in a high temp environment causes excess transpiration, the plant is attempting to hydrate and cool itself at the same time and it's an overload.
 

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