Help with Jock Horror leaf spotting

Hi all! long time lurker first time poster!
This is my first grow, strain is Jock Horror Auto's. There 18 days old & seem to be growing slowly.
Hydro grow in a 4 gal tub with 2 air stones & a 160 gph pump recirculating water (i also have two drippers hooked to it)
Light is a 150 watt HPS & a 65 watt 6500K CFL. The HPS is 14" from top of plants & my temps range from 72-76 lights off to 78-85 lights on.
Humidity ranges from 38%-55%.
Added a very very light dose of Sensi Grow 7 days ago (7 ML to 4 gal)
PPM is 200 & PH ranges from 5.8`6.5, somedays it jumps around & sometimes it stays pretty consistant. Im just using tap water.
Water temp ranges from 74-78.
Lights are on 20/4.
I have seen a couple gnats flying around in my cabinet.
Root growth looks decent but once again this is my first grow so i dont really know.
Cabinet is 2.5x2x5, exhaust fan, & a 4" fan blowing on the plants.
Now to my problem.. The first set of leaves started getting spots a few days ago on one plant, on one leaf & now the other side has started doing the same. I have also noticed on a couple other plants there is some tiny tiny yellow/brown specs forming. I have 5 plants total. Heres some shitty iphone pics maybe someone can help me out a little. Maybe a Magnesium or Calcium efficiency? Thanks in advance!

they were only 11 days old when you fertilized them which could be the cause.. that's my 2 cents. GL

Po boy said:

they were only 11 days old when you fertilized them which could be the cause.. that's my 2 cents. GL

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Maybe it was 5 days ago i added nutes because it was 13 day old plants & i had read at 2 weeks you could add 1/4 strength nutes. I only added 1/8th (ish) strength.
I should really start writing this shit down!

Babies need food just as much as adults do in hydro, especially a DWC. People really over complicate this. Just feed it 700-900 ppm throughout the grow and raise to about 1200ppm for the stretch period, then back down between 700-900. Plants need food. You wouldn't feed your baby 1/4 strength milk would you? It's not going to drink a gallon at once, it drinks slowly! It's not going to get bone burn with full strength!

200ppm is way too low for any size/age plant. Of course that's the problem.

Also, keep pH between 5.5-6. Don't let it go above 6 or it will block out iron and other micros. pH will also be much easier to keep stable with a higher ppm as it means higher buffering capacity.

When I first started growing, the most common problem was overfert and over watering. Now, everyone's warned so much of overferting, people are afraid to feed their babies!

churchhaze said:

Babies need food just as much as adults do in hydro, especially a DWC. People really over complicate this. Just feed it 700-900 ppm throughout the grow and raise to about 1200ppm for the stretch period, then back down between 700-900. Plants need food. You wouldn't feed your baby 1/4 strength milk would you? It's not going to drink a gallon at once, it drinks slowly! It's not going to get bone burn with full strength!

200ppm is way too low for any size/age plant. Of course that's the problem.

Also, keep pH between 5.5-6. Don't let it go above 6 or it will block out iron and other micros. pH will also be much easier to keep stable with a higher ppm as it means higher buffering capacity.

When I first started growing, the most common problem was overfert and over watering. Now, everyone's warned so much of overferting, people are afraid to feed their babies!

Click to expand...

Thanks for the response! The 4 gal tote bubbler is just a temp & I will be finished with my (5) 2 gal bucket RDWC tomorrow hopefully. What other Advanced Nutes do you suggest for this Auto Strain? And should I bump it up to 700 all at once or should I do it gradually. You are correct about the info on everyone saying NO NUTES, that's pretty much where I've got all my information! Once again thanks for the helpful reply!

IMHO, 700ppm is way too high for seedlings. I came up with a very basic rule of thumb, though -- 2 weeks old, 200ppm; 3 weeks, 300ppm; 4 weeks, 400pm, etc...up to flowering. Then hang at 800 for flowering and back off to about 600 the last few weeks. Very successful for the strain I was growing, no burn.

Now back to your problem -- what's the ppm of your tap water? Mine's on the low side -- 140. So I also add CalMag to the mix in addition to the 3-part AN nutrients I use.

PH should be 5.6-5.8 most of the time for best nutrient absorption in hydro. Higher than 6.2 and the plant won't get much of anything. My ph went through phases of fluctuating up or down about .4. For weeks it would be up at 6.2 or 6.3, then for weeks it would be down at 5.4. I hit 5.8 on my readjustments, which I did morning and night.

Good luck! And yes, you should keep your own grow log for each week -- what techniques you're using, what problems you may be facing and notes to yourself on what you'd do differently on the next grow. VERY HELPFUL. A synopsis of all that is in my auto signature so you can see what I mean.

Thanks again for another helpful post! Anyone else have a suggestion?