pH problem?

[messn'n'gommin']

SOIL:

How long has this problem been going on? 2 weeks +/-
What STRAIN are you growing? bagseed
What was the establishing technique? (seed or clone?) seed
What is the age of your plants? 5 weeks 4 days
How Tall are the plants? 7-9"
What PHASE (seedling, vegetative or flower) are the plants in? veg
What Technique are you using? (SOG, SCROG etc) LST
What size pots are you using? (Include how many subjects to pot) approx 3 gallon
What substrate/medium are you using? What brand of soil mixture are you using?(percentage of perlite, vermiculite...etc?) MG moisture control
What Nutrient's are you using?How much of each with how much water? How Often? *Knowing the brand is very helpful* Alaska fish emulsion 1/4 strength at about mid week 3 and mid week 4
What is the TDS/EC/PPM of your nutrients used?
What is the pH of the "RUN-OFF"? less than 6.0
What method of pH test was administered? Using Strips? pH pen? Narrow range drops (6.0-7.5)
How often are you watering? 3-5 days
When was your last feeding and how often are you feeding? about mid week 4
What size bulb are you using? 2-250w CMH
What is the distance to the canopy? 10-12"
What is your RH Factor? (Relative Humidity) mostly 40-50% (occasionally 30-60%)
What is the canopy temperature? haven't measured
What is the Day/Night Temp? (Include fluctuation range) 70-85F
What is the current Air Flow? (cfm etc.) not sure (am using stanley blower mod and set at highest speed)
Is the fan blowing directly at plants? no
Is the grow substrate constantly wet or moist? moist
Is your water HARD or SOFT? about 110-125 ppm
What water are you using? Reverse Osmosis (RO)? Tap? Bottled? Well water? Distilled? Mineral Water? RO at first and when the leaves started turning yellow 2-3 weeks ago I substituted tap that had sat out for 24hours
Has plant been recently pruned, cloned or pinched? topped at about 4 weeks
Have any pest chemicals been used? If so what and when? BT at end of week 4
Are plant's infected with pest's? springtails (but it is my understanding that they don't or rarely eat live plant tissue)

I flushed with tap water that measured 7.5 or more last Monday and Tuesday. I dissolved pelletized dolomite lime, as best I could, at 1 TBS per gallon of 4 gallons tap water and flushed the two sickest plants (3 and 4) with one gallon each and the runoff was measured at about 6.2 or 6.3. They showed the effects of overwatering for a day or two then perked up but none have really shown any real growth fir the past week. Since then plants 1 and 2 are showing signs of the same thing. Am I right in assuming it is a pH problem or could it be something else like underfeeding? I am a bit hesitant to add any ferts, because if it is a pH prob, I would just be making things worse. So, I come to you with hat in hand seeking advice and counsel.

Plant 2 (the healthiest...lol...definately a relative term))




Plant 4 (the sickest)





Namste, mess

 

[Snype]

I'm pretty sure that MG soil has a lot of nutes in it already and if that's true you could be over feeding. Also I didn't understand your answer to this:

When was your last feeding and how often are you feeding? about mid week 4

Also 7.5 PH is pretty high. I would flush them for at least a week. I also think that you're over watering too. I let my pots dry out and I pick them up one by one and feel the weight of it and let it get to the point that it was when I originally put the soil in the container. The pests don't help either. Good luck with you're grow. I hope it works out for you.

 

[Snype]

Seems like your soil has a lot of nutes in it already and can hold a lot of water. I looked up that soil and here is what it said:

Miracle-Gro® Moisture Control® Potting Mix
Desired Results
Absorbs 33% more water than ordinary soils, to protect against over-and under-watering.
Benefits
Feeds plants for up to 3 months.
Fertilizer Analysis
0.21 - 0.07 - 0.14

 

[messn'n'gommin']

I'm pretty sure that MG soil has a lot of nutes in it already and if that's true you could be over feeding. Also I didn't understand your answer to this:

When was your last feeding and how often are you feeding? about mid week 4

Also 7.5 PH is pretty high. I would flush them for at least a week. I also think that you're over watering too. I let my pots dry out and I pick them up one by one and feel the weight of it and let it get to the point that it was when I originally put the soil in the container. The pests don't help either. Good luck with you're grow. I hope it works out for you.

Sorry about that, I just read the first part when I responded. I had last fed 1/4 strength (1/2 tsp in one gallon RO for 4 plants) fish emulsion at about middle of week 4 and the only other time I had fed them was about middle of week 3. The 7.5 plus pH is the tap water after sitting out for 24 hours and before flushing. I thought I had been watering with RO water a bit on the too little side as I was watering about every 4 or 5 days when the soil was starting to pull away from the sides of the pots. Even then it was only about a quart each plant. Since then I flushed earlier this week with tap water and the soil is still a bit moist, but was unsure if I should flush again or to just start watering normally. As for the springtails all the research I have read says that they feed on dead veg matter that makes up a lot of the potting soils, peats, etc., and rarely if ever living plant tissue. But I have believed false statements before and this could very well be another.

btw: Thanks for the info on the MG.

Namaste, mess

 

[B.C.]

hhmm...

hhmm...

Seems like your soil has a lot of nutes in it already and can hold a lot of water. I looked up that soil and here is what it said:

Miracle-Gro® Moisture Control® Potting Mix
Desired Results
Absorbs 33% more water than ordinary soils, to protect against over-and under-watering.
Benefits
Feeds plants for up to 3 months.
Fertilizer Analysis
0.21 - 0.07 - 0.14

Hey guys these ^^^ numbers are not even whole numbers, so it's very lil for fast feeding plants like pot. I think you may have had a slight lock out at first ( hence the spotted older fan leaf ), from the combo of fish emulsion and RO water. Fish emulsion has a low PH ta keep it stable and RO water is low ta start with. I think ya need ta feed them. Most of the older leaves are an even yellow at the bottom, and the newer growth is an even pale color ( no spots ). When yer PH goes slightly outa whack yer plants will show spots because it's only lockin out a few different nutrients not all of them. I'd feed em, and use yer tap water. The PH would be much closer ta where ya need ta be. I'd keep bumpin the feed till ya see em green up. These plants are gettin bigger now and will want to eat, that slow release fert ( what there is of it ) jus isn't gonna do it..... Suggestion for next time useing this soil. Add 25% worm castings or compost. The microherd and the humus will make yer soil very fergiving for the plant as far as PH swings, nute def, heat stress, etc... I hope this helped some, good luck! Take care... BC

 

[messn'n'gommin']

I will try half strength fish emulsion in one gallon of tap water at about a liter/quart per plant this evening.