Help with my sickly hydroponic plants

[germkillah]

I have some sickly-looking Super Skunk plants and they're about five weeks old. I'm using Humboldt's Secret A-B nutrients and following the instructions to use about half the recommended amount. The directions say 1ml equals 40ppm, so I have been using about 4ml of each for my five-gallon buckets. My pH is stable at 5.5. The room temperature is a bit high at 81 degrees and my light is a KingLED 1000-watt, which is probably more like 250 true watts.

What could be causing the plants to look so bad? Is my nutrient mix wrong or is the water too warm?

 

[vickie_05]

I had a tough time with Super Skunk in my first DWC grow last year. It's a good plant but needs extra care early on. Your pH at 5.5 might be a little low, try raising it to 5.8 or 6.0 to help the plants take in food better. Also, 81F is pretty warm for the water. Roots don't like it much above 75F. You can cool it down with a frozen water bottle if needed. At five weeks, 400 PPM is low. Try slowly raising it to 600-800 and see how the plants react.

 

[HELYAB]

It sounds like you have the basics down but there are a few tweaks that might perk them up. At 5.5 your pH is at the lower end for vegging plants; creeping it up to the 5.8 to 6.0 range will help them take up more calcium and magnesium. Super Skunk can be a heavy feeder once it gets going, so 4 ml each of A and B in five gallons is quite mild. You can slowly raise the nutrient strength and watch for tip burn. Also, 81 F reservoir temps can cause dissolved oxygen levels to drop and invite root issues. Ideally keep the water around the mid sixties by using frozen water bottles or a chiller to knock a few degrees off. Finally, make sure your LED is at an appropriate distance because too much intensity can stress young plants. Once you dial those in they should rebound quickly.

 

[black codez]

So the recommendation is to get a PPM/EC meter. That's very crucial. Then adjust your pH. Check your nutrient mix. Start with a lower PPM (around 600) and work your way up if the plants show no signs of improvement or if new growth looks pale. And manage your temperature. Ensure you have adequate air circulation to prevent heat stress.

 

[Iron Baron]

It sounds like you have the basics down but there are a few tweaks that might perk them up. At 5.5 your pH is at the lower end for vegging plants; creeping it up to the 5.8 to 6.0 range will help them take up more calcium and magnesium. Super Skunk can be a heavy feeder once it gets going, so 4 ml each of A and B in five gallons is quite mild. You can slowly raise the nutrient strength and watch for tip burn. Also, 81 F reservoir temps can cause dissolved oxygen levels to drop and invite root issues. Ideally keep the water around the mid sixties by using frozen water bottles or a chiller to knock a few degrees off. Finally, make sure your LED is at an appropriate distance because too much intensity can stress young plants. Once you dial those in they should rebound quickly.

I grew Super Skunk in deep water and it started growing fast once the roots got big. I had to use about 6 ml per gallon to keep it healthy. When my water hit 81 F, the roots got sick, so I used frozen water bottles and changed them twice a day. How strong is your mix now and how old are your plants?