A newb and his first grow, plant deficiency or burn?

A little about the room

5 weeks into flower
Soil-less sunshine mix #4
Lights: (4) 1000w parabolic HPS and minimum bulb distance 24"
Sealed room w/ 1200-1500PPM CO2
Temperature 86* Day, 82* night (thermostat controlled)
Humidity 38-55% RH
Nutes: FF Trio, 10ml/gal tiger bloom, 15ml/gal big bloom (tea)
CalMag+ 2-0-0 @ 5ml/gal
Ph IN: 6.4-6.5, Ph runoff is 5.1-5.6
Water: 0-50 PPM (I take the condensate drain water or RO from the sink)

I am growing many different strains which now seems like a bad idea given how they all grow differently but a few have started to show deficiencies at week 5. I thought it was nute burn so at the beginning of the week I started watering/leaching with RO/Distilled water and things got noticeably worse in the last 3 days. After starving them of nutrients I just watered with 5ml big bloom, 5ml grow big, and 15ml big bloom, and 5ml calmag since it now appears that it might be a deficiency and not burn. I always measure the pH of incoming water @ 6.4-6.5 but today I decided to take runoff samples from many different pots after watering and the runoff is anywhere from 5.1-5.6 depending on the plant. It now looks like a lockout of Cal/Mag but I just wanted some opinions. I might start watering at pH 7.4 or so because the sunshine mix seems to be dropping my pH by 1.0 or so consistently. Can anyone very roughly estimate what my yield might end up (if they don't die) at based on the pics?

I have come to the conclusion that my soil pH is too low to absorb calcium and magnesium as well as some other nutrients effectively. I'm going to spinkle some dolomite lime on the top and try to gradually increase my pH in the water feedings to see if they make a recovery. From what I understand it will take at least a week for the lime to break down but hopefully increasing the pH to 7 or so for watering will hold it over. I think the buffer that came with the sunshine mix already broke down since the soils been used for 12 weeks already or so and the peat moss is lowering the pH significantly to cause lockout.

Lime should help but, are you sure it's not salt build up? I would flush very well with water and then go from there

Doing that tomorrow, you are probably right. I measured runoff PPM and it was over 2,000.

keep it real. said:

Lime should help but, are you sure it's not salt build up? I would flush very well with water and then go from there

Click to expand...

yea 2,000 ppm sounds about right for your problem, im glad you got it figured out.

That's a sweet setup for a first time. Nice.

I flushed them until the well water ppm (200) going in was the same ppm going out and didn't add any nutes. I also added 3/4 cup of lime and dressed it on top. I learned not to add the lime first or else it takes forever to flush since the lime powder turns into a slime. I'll add 1/2 strength nutes in a few days, is there a way to avoid buildup like this? It's a lot of work to flush so maybe I'll just do 1/2 strength nutes from now on.

Most problem arise for only a few things.

The first being, overwatering. Not so much that your giving them to much , but to often. Dont get me wrong to much will have affects on yields, but from experience just as long as you only water when there bone dry you can still get a decent crop off. The best solution for overwatering is using h202 or roots exceleratur . You can only use 1 or the other. h202 will kill roots excel. I like to use roots in first 2 weeks then h202 , it keeps stuff sterile and almost impossible to overwater.

Next problem is over fertilizing. Less is always better. I wouldnt recommend more the 600 ppm in full veg , but make sure you start around 200 ppm or less and increase in small increments to help them adjust and then you can read what the plants like. Always water with room temperature water.What ever your fert jugs says for ppm, but it in half.


In sunshine mix ph should not be a issue becuase it has lime and almost all fertilizers are ph balanced . In fact i dont ph dirt at all anymore because with g/h food's my runoff is always 6.3 in dirt.

Last thing is your enviroment. You need a min/max gauge to know high's and lows of your room and this very important if your room is dipping down to 10c for a hr or 2 lights off. Or hitting 33c lights on .

Your plants are way to over fertilized. Water the shit out of them with 400ppm food and let them dry out. Dont going on a watering schedule .......water when they are almost wilting with just water. By now your plants should be healthy and you can resume increasing ppm by 100ppm each feed.

I've read that when watering, catching it when it just dries out is good, but repeatedly letting them sit for a couple extra days too dry will tend to give you the salt build up faster.