Small spots on first set of leaves

[hoosierdaddy]

This is an Orig Thai Haze x Skunk #1
Cast in MG potting mix, watered with dechlorinated tap (sat for 4 days). (didn't test, normally tests at ~6.8)
Pic is of 8 days, spots appeared on day 5.
Under CFL about 3"



I am not real concerned about this since the oncoming leaves are not showing this at all, but I am curious of anyone knows what may cause these spots?
I have a feeling it could be the dose of immediately available N that the mix provides, but not sure.
I have 2 other strains cast same day, same mix, and are not showing any problems at all.
Strain related issue?

 

[hoosierdaddy]

Three dozen people check out this thread, and not one comment. Wow.
Maybe it's because I didn't fill out the sheet?
This thing is starting to concern me since it is now showing on the new sets of leaves.
OK....
I checked Ph and nute level. so I could have valid data...

How long has this problem been going on?
5 days

What STRAIN are you growing?
Original Thai Haze x Skunk #1

What was the establishing technique? (seed or clone?)
From seed

What is the age of your plants?
10 days old today

How Tall are the plants?
~2"

What PHASE (seedling, vegetative or flower) are the plants in?
Seedling 1st and 2nd set of leaves established, first full set emerging.

What Technique are you using? (SOG, SCROG etc)
Cast in potting mix

What size pots are you using? (Include how many subjects to pot)
Party beer cups

What substrate/medium are you using? What brand of soil mixture are you using?(percentage of perlite, vermiculite...etc?)
Miracle Grow Potting Mix

What Nutrient's are you using?How much of each with how much water? How Often? *Knowing the brand is very helpful*
No nutes.

What is the TDS/EC/PPM of your nutrients used?
Soil/water slurrry tests low ppm

What is the pH of the "RUN-OFF"?
Soil/water slurry tests at ~6.3

What method of pH test was administered? Using Strips? pH pen?
Cheap test meter

How often are you watering?
Only when cups feel light

When was your last feeding and how often are you feeding?
N/A

What size bulb are you using?
42watt CFL

What is the distance to the canopy?
3"-4"

What is your RH Factor? (Relative Humidity)
~45%

What is the canopy temperature?
~80F

What is the Day/Night Temp? (Include fluctuation range)
75-80 deg F

What is the current Air Flow? (cfm etc.)
Enough to make the seedlings just barely dance

Is the fan blowing directly at plants?
No

Is the grow substrate constantly wet or moist?
No

Is your water HARD or SOFT?
Water is not overly hard, comes from well fields

What water are you using? Reverse Osmosis (RO)? Tap? Bottled? Well water? Distilled? Mineral Water?
Tap water that has set for several days

Has plant been recently pruned, cloned or pinched?
No

Have any pest chemicals been used? If so what and when?
No

Are plant's infected with pest's?
No








MOC Carvival (mostly sativa) lush and thriving well cast same day, same mix, same water.



Mandala #1 lush and thriving well cast same day, same mix, same water.

 

[Snype]

Can you tell me what is in you're miracle grow soil? Does it have time released ferts?

 

[hoosierdaddy]

It does have time release ferts and some immediately available N.
.21-.07-.14

 

[Snype]

I personally wouldn't use that but I would give it plain water and lower the PH to 6.0-6.5.

 

[hoosierdaddy]

Snype,
Mandala suggests casting seeds right in the growing medium, and also calls out MG potting mix as a good choice by name. Although I realize this thai genetics is not a Mandala strain. I have a feeling it is the available N that is in the mix that this plant does not like. The time released ferts don't concern me much. They are really not a factor yet.

And on the Ph recommendation...

What is the pH of the "RUN-OFF"?
Soil/water slurry tests at ~6.3

But I do appreciate your help though.


Perhaps a better place to post this issue would be in Sams thread......

 

[Snype]

sorry I couldn't be of help. Hope it all works out for you.

 

[MynameStitch]

mg soil has too rich of soil, especially for seedlings.... I would flush the plant out with alot of water..... use around 2 gallons of water to flush each plant out..... you should always dilute mg soil, it cn even be too hot for adult plants......

Dilute it with 50/50 with mg and another brand......

 

[hoosierdaddy]

I was hoping that a good flush would be the solution.

I have grown a few plants using nothing but MG, and have never had any problems with N burn. Everything I have grown so far in it seems to thrive quite well. The plants I have now (Mandala SM & bagseed) have been it it since day one (now into 41 days of 12/12), and have not asked for any nutes at all. So I have to assume this incident is pretty much strain related.

If I have not had any other issues, and the other seedlings I have now are doing quite well, do you still think I should flush them too?

 

[MynameStitch]

mg recently changed and put timed release ferts.
I used to use it as well and I used to use it straight or mixed 50/50

but when they changed the formula I could no longer grow with it straight up due to it being rich and nutes were to strong. Not to mention timed released ferts, cold water and temps can cause the nutes to be released at a stronger dosage which burns the plants even more.

Also all strains are different, some can take more nutes where others are more picky and burn easily........ I would only flush the ones that uis showing symptoms, do not flush the ones that are not sickly.

 

[hoosierdaddy]

Ah, your post is exactly what I wanted to hear.
I was also worried about the change in MG until I saw that my cabs test plants were thriving in it. I also worry about the consistency of batch when dealing with salts.
Seeing that the mix is at best on the verge of being too hot, I will take your advise and reformulate with a cut of some sort. Although I may have to do some searching, as I do not, and will not, visit hydro stores.
Perhaps a cut with perilite/vermiculite would be in order? I have also considered changing altogether to coco...what are your thoughts on that medium?

Your wisdom and time are much appreciated, ms!

snype...do not think I didn't appreciate your time as well...out of 70 some odd visits, you and ms stitch were the only ones to offer a comment.