Slow growing and brown spots.. help please?

[crinkles]

Hey Guys,
Hoping you can help keep my seedlings alive! Here are as many details as I can think of:

Number of plants: 4
Age of plants: largest plant day 26, rest about 20
Strain: BC Ice http://bcseedking.com/bc-ice.html

Area: Micro grow in stacked tube, in a smallish spare room/computer room.
Venting: 150cfm panasonic fan
Lighting: 2x42w CFL / 5 x 27W CFL

Medium: Soil (Premier brand 'mix of soil, peat moss and perlite', does not appear to be enriched) mixed with about 30-40% perlite. Drainage excellent.
Nutrients: Plan on using Plant Prod 20-20-20 when called for, only put 1/4 strength in one feeding when I thought it was the problem.. made it worse
Water: Storebought RO PH approximately 6-7 with vial and card
Temps: Daytime 73-78, 82 max, Night 68-73, 65 min.
Humidity: was 40% now about 50% since transplant

First attempt at 'FIM' 4 days to a week ago.

Overall plants look strong, you can see the bottom leaves look much worse (some I cut off) due to my early nut'ing. I thought they were balancing out as new growth appeared green and the spikey edges were laying down but the rust is spreading upwards, especially on the larger plant.

They get water every 3 days or so, was 2 days in the solo cups. Dries very quickly with that fan! Started in solo cups, transplanted into 8" hoping that was the problem.

The soil was from the shed, stored opened and partial since the summer (hopefully a few weeks of -30C would be enough to sterilize??) Trying to do this as cheaply as possible.
Bought new bag for transplant.

Thanks everyone!

 

[Desert Hydro]

probably just fried from feeding too soon. ive killed many a seedling this way lol. killing em with kindness is too easy and it sucks. they may be too far gone to save, or it may even be faster to start some new ones if you have extra

 

[shredGnar]

Perhaps get a two or three part nutrient system that is more tailored for cannabis, and start them off with that at a quarter strength..

Not sure how great that 20-20-20 is going to treat you!

Shred

 

[crinkles]

Thanks guys! Not excited about the prospect of starting over... It took 2 weeks of germinating and almost a month of veg to get to this point. the other 3 plants are affected but not quite as bad, the plant shown had green upper leaves until yesterday. im hoping its not too late!
I figure either there are residual nutes from the feeding (did give a flush before transplant) or naturally in the soil slowly killing it, or it it showing signs of nute deficiency (mg? Calcium?) i dont want to feed anything if its already over fed and vise versa!

I live in a small city in northern Canada and am pretty much limited to canadian tire, walmart and home hardware for supplies. I can look for some specialty nutes if anyone thinks its a deficiency.

Thanks!

 

[shredGnar]

I would certainly order some nutrients online..

Kool bloom powder from GH is a simple one parter, also look into veg and bloom, made by hydroponics research, another one part powder nutrient, that is popular with board members here.

I think the 20-20-20 fert you started them with caused a lock out and now they are unable to obtain the minerals they need..

Get some new nutrients and try them out, but perhaps sart some new beans in the meantime.

 

[Sat X RB]

Mate, I 'm sus about that soil yr using ... and all the perlite in the mix.

if yr using a growing medium that's 60% soil+peatmoss+perlite ... and then y've thinned that down with 30/40% perlite ... there is very little nutrition in yr mix. the only nutrition will be in the 'soil' component ... and whatever is in liquid form from yr nutes that remains soaked into yr perlite. that is: not much!

so yr plants aint gettin enuf food. and you may already have watered out (flushed) whatever food was originally in there with the watering y've done so far.

adding 1/4 strength nutes probly did nothing. not enuf nutes and lots of water ... so water water everywhere but no food to eat.

unfortunately yr going to have to transplant into a better growing medium ...

neither have you referred to soil pH. it may be written on the bag, and seeing as it's commercial it MAY be somewhere near neutral (7.0). however you need to know this so a soil pH kit is necessary.

seeing as you haven't talked about soil pH you probly haven't included Lime, or better still Dolomite, in yr mix. Dolomite provides both Ca and Mg. those spots on yr leaves ... if they're not a sign of past overwatering may be a sign of Ca shortage.

BUT yr whole soil mix is probly out of whack pH-wise because the peat moss in yr mix is extremely acid! perhaps as low as 4!!!! in short yr soil mix is TERRIBLE! (and I say that in the nicest way ...)

I see yr short of suppliers where you are ... but still you should have a choice of soluble ferts. 20-20-20 is not useful! firstly look for ferts that contain trace elements. generally at this stage you need high N, some P and some K . later on you'll need to change this to favour K.

but look for other soils and pH test them so that you have a baseline for any future difficulties ... I suppose where you are the ground is too hard at present to dig local soil? (if you can't do anything about obtaining other soil at least leave out the peat moss in yr new mix.)

don't be afraid of transplant ... just be gentle and don't break the roots.

come back, y'all ...

cheers from Oz!

 

[crinkles]

Thanks again for the tips! Of the four plants, the one in the photo is the worst (and also the oldest by about a week). The other three show much less trouble (very mild brown spots on a couple of leaves), only symptom is small size.

I have done some more reading on nutes and it seems that the ideal ratio for veg is 3-1-2? I found some liquid 12-4-8 at the hardware store, expect this would be more appropriate?

I did another flush just in case it was residual nutes and will wait another week before I decide if I should get new soil and try again. In the mean time I found a single serve soil test kit at the hardware store - Soil PH was a bit high actually (7-7.5.. hard to read the colour chart), nitrogen and phosphorus didn't even register and potash was low.

I will do more reading on raising the soil PH in the meantime, considering giving some nutes next watering as I see the large plant leaves are becoming less green.

A comment on watering, they have never been over-watered. I have given a few good soakings on my journey to health but always let the soil dry out in between. About 2 days to a 'light pot', usually gave an extra day to be sure.

Thanks!

 

[crinkles]

Oh, and I do PH my RO water, comes in around 5.5-6.

 

[Sat X RB]

well yr pH reading is a surprise to me.

if yr pH is 7 and up, include vinegar ... sorry don't know how much ... in yr next water to bring it down to 6.5 or thereabouts.

yes, 12-4-8 sounds good.

good luck!

 

[shredGnar]

That pH is probably causing issues as well..those numbers are perfect for coco or hydroponic but for your soil it should come out around 6.3.

Try using that new nutrient you got at 1/4 strength with a proper pH.

Were you using pH down to get the RO water that acidic??

https://www.google.com/search?q=can...hl=en&client=safari#biv=i|1;d|sOkA0vF0G1dbGM:

 

[crinkles]

I have done nothing to the water. I had previously tested a bottle (grocery store big blue exchange bottle) closer to 6.5-7, this is a new bottle from same store. Possibly issues with my test method or the kit but its a pretty standard kit from a pet store (Nutrifin) and the test is simple - 4 drops in 5ml water, shake and compare. I hate these colour charts but over/under is simple: anything green is alkaline, anything yellow/orange/red is acidic. Usually comes out orangish so hard to gauge. I tested my tap water for fun and it came out medium green, about the same as the soil sample.

For fun I will soak some of the untouched bag dirt in water for half an hour and see how that tests out.