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help wilting and yellow leaf on bottom in dwc

Thread starter #1

I have a dwc system plants are 3 weeks in to flower and 3 out of 8 are wilting and the lower leaf are yellow and falling off. top of the plant looks ok-ish looks limp.

ph 5.8
ec 1.4
room temp 28 cant get is any lower at the mo.

Anyone with advice?

Just been and had a look. the top of the rockwool cube are wet? do you think I have to much water in the buckets and drowning the plant? I have just drained some water out.

How far should the bottom of the net pot be from the water level?

Keep your water level at least 1.5 inches below the bottom of the net pots. the plants need am air gap. Also make sure you have plenty of air in the res. You want your water temp at about 67 as that is the optimum temperature to hold dissolved oxygen. What is the water temp? what do your roots look like? can you post a picture of the plants? also this link will take you to a good pictorial on growing issues...

Thread starter #3
Hi 2BL

my net pots were 2inches above the water so just put some more water in. I have put the lights on at night now and put 1 cool tube in room temp 26 water temp is 72. Looked at the link you posted and my roots look like heat stress from the photo that were on the link. Just had a look an the tent and 2 more wilted they were fine last night before the lights came on. so will look tonight and see how they look after 12 dark. Am starting to think maybe I should have stayed with coco.
Hydro can have a learning curve, I chose it because I dont want a bunch of bug attracting dirt in my house. I killed my first plant in like two weeks, but I am learning. Are you feeding them nutrients and if so are you doing full strength, most everyone on here that does hydro run the nutrients at 1/3rd or 1/4 strength. What is the Humidity of the room? The temp of the room is probably ok but would be better a little lower. Have to get water temp down though, high water temp promotes bacteria and holds less dissolved air. I had a bunch of issues when I was starting my grow, water temp to high, humidity to low, cabinet temp getting to high. I fixed the cabinet temp and humidity with a cool air vaporizer and purchased a water chiller for the water. After that I started running my nutrients at 1/4 strength and and have seen explosive growth in the last week. Take a look at the pictures in my grow journal in my signature you will see my girls had the droop-ies and my Afganhi Kush x Skunk still shows some war wounds from my inexperience but she is recovering.
Thread starter #5
Still having trouble with the heat> aaaahhhhhhhhhhhhhhhhhhhhhhhhhhhh

lights off 23
lights on 29 with 2 cooltubes and a 6 inch fan from outside throw the lights and out the other side.
water temp lights off 21
lights on water temp 25 to 26.

Can anyone give the the perfect temps for dwc ie, room lights on and water temp.
I think I will have to dump these 8 until I can dial the temps in right or else I will just be killing the new ones.


You want your air temp to not get over 32 at the max, 29 should be ok for air temp. It is your water temp that is hurting you. You can get those ice blocks and put them in to bring down the temp but i recommend investing in a water chiller and get the water down to 19. Since most water chillers start at $350 I found one based upon the peltire chip and cost $250 it is much smaller and works perfect, my temp is 19.4 light on or light off even when my cabinet gets over 26.

My Water Chiller
Thread starter #7
Hi I brought one of those kits from ebay for £20 just waiting for it to come, how much water can they chill??? I have 9 buckets on a rdwc.

today I have umpluged my control box for the in and out fans and just plugged 100% in the mains just to see if the temp drops. Put a fan over the rez to cool
I need to get every think perfect because I have some critical kush ready to flip. and I don't want to kill them
A water chiller for 20 pounds I cant imagine it does much at all. How many liters of water does your system hold? I only have a 5 Gal res and it keeps it at 67 degrees perfectly
Thread starter #9
Yep £20 for this Thermoelectric Peltier Refrigeration Cooling System Kit Cooler fan + TEC1-12706 with a water block. Looks the same as your photo if it works will mite get one for in the tent as it is only 12v .

anyway I was playing around with fans and ducting yesterday, after light were on for 2 hours I checked and the top was 26.4 and bottom 26.6 so happy with that. water with lights off 19 and lights on 25 I have a rdwc 8 buckets plus rez I guess each buckets has 2.5gallons so total 22.5 gallons.
Found it, I was going to build the exact same one. The price is good. Two things stopped me the water reservoir being aluminum and only being 40mm x 40mm and I was worried it couldnt cool my res and that the aluminum would taint the water. I ended up going with this one:
CSXC-1 Aquarium / Hydroponic Chiller | Chill Solutions works perfectly for my 5 gallon reservoir temp is always at 67 degrees. Also are you running any bennies and enzyms in your res to prevent root rot. What do your roots look like?
Thread starter #11

The part came and it was rubbish. So just brought a fish tank water chiller for £250 does up to 300 litres. its a D&D DC300 chiller.
Hopefully this will sort out my trouble.

in the link you sent me last week my roots are like a photo in there and it said heat problem. I did put some h202 in last week and have new roots showing when I looked about 3 days ago. my room is 26,9 bottom of tent and 26.4 top of tent so very pleased with that at the moment. just hope the 8 plants I have in the tent recover now
Thread starter #12
Put the chiller in set to 18 and room is 26 just hope the plants will be happy now. they have just started to flower. what ph and ec would you go for?????? this is my first rdwc grow from switching from coco for years. had a look at the roots and there are new white roots coming.
Here is the PH range chart. The sweet spot is 5.8 for Hydro but anywhere between 5.6 and 6.0 is good. Good choice on the new chiller you want your temp to be 67 degrees F, sorry I'm American and dont do metric to well but that is where water holds the most oxygen and will also help keep the root rot at bay. Are you running any hydroguard and beneficial's to keep your roots healthy?

Thread starter #14
67f is 19.4c
mine is 18 which is 64.4 I guess is should make is 19c then.

just cleaned everything out put fresh water in ph is 5.7 and ec 1.3 that is with canna aqua a&b

just turned the white widow to 12/12 they had nice white roots in the veg room so fingers crossed.

as for your question (Are you running any hydroguard and beneficial's to keep your roots healthy?) what do you mean? h202??
as for your question (Are you running any hydroguard and beneficial's to keep your roots healthy?) what do you mean? h202??
H2O2 can help clean up root rot but products like hydroguard and Orca or Great White add beneficial bacteria to your reservoir that keep root rot from-ever starting and aid the plant to us nutrients. They keep your plants healthy and eating properly. Orca is the same as Great White but in liquid form for hydro.
Thread starter #18

Just an update all the plants that had gone yellow from lack of nutrients have come back a nice green with lovely white roots so pleased with your help 2BLgL.
Glad I could be of help to a fellow grower.
Thread starter #20
hi just an update
start of week 9 today just harvest all plants look great will update a dry weight soon. The water chiller works great.