Yellow, Pale Leaves. Deficiency Or Late Flower?

[notacriminal]

I've got a bit of a problem. My fan leaves have been turning yellow over the past 5 days, with one of them having some heavy curling today. The tips also looks slightly "burnt" on some leaves..
Bud growth has also seemed to slow down to a near halt, if not completely, although it is still forming trichomes from what I can see.
I'm wondering if it's a nitrogen deficiency, a root problem ( i had what i assume to be gnats for a couple days ) or if it's just because I'm in late flower. Harvest day is an estimated 8 days from now.
The strain is an Auto Speed Bud on day 45.

It's worth noting that, going through my picture log, I can see these problems started immediately the day after I watered on top of diatomaceous earth. My diatomaceous earth has a mildly deodorized smell to it, so I'm a bit worried it's contained something that's harmful to my plant. Package only lists "90% pure diatomaceous earth, 40-50% silica". It is sold as a nutritional supplement from a local health store.
Could it be that the diatomaceous earth has blocked out nutrients for my plant?

Also worth noting, this is a bit of an experiment in that I haven't used commercial fertilizers. I've used diluted urine and boiled crushed sunflower seeds exclusively, which hasn't resulted in any sort of deficiency, 500ml per feeding. I've also always adjusted the pH to be around the 6.6~6.8 range. I watered with this solution again yesterday for the 3rd time. The other times it has had a noticeable increase in growth, but this time it didn't seem to do much.
I water every 3-5 days, after the top inch of soil is dry, with pH regulated tap water, leaving it out a day or two to let anything nasty disperse first.
There is also a layer of perlite on top of the soil which has turned faintly green/blue after being watered a couple of times.

I've attached a picture showing the plant as it was as of today. You can see the curled leaf in the lower left.
The thermometer is off by 2-3 celsius, and the light has been off for about an hour at this point.
Light is a 300W advertised wattage LED, 100W actual wattage.
9L pot using standard potting soil. Plant has also been lightly trained.

Hope you can ease my mind a bit. Thanks.

 

[notacriminal]

Here are two additional pictures, one after applying diatomaceous earth, the other the day after watering on top. The leaves have already turned a little pale, after just a single night.

 

[tinderthumbs]

what size light u using?

 

[notacriminal]

300W LED, 100W actual wattage. It's in the OP, too.
If you mean physical size, it's a 178mm diameter UFO style.
Canopy is ~55cm from light.

 

[Onetwothree]

If you're harvesting 8 days from now then it's just late flower. But to my eye those buds don't look ready. I have no experience with LED's though. I'm used to seeing the fatness of an HPS. To me it looks like an N deficiency.

 

[notacriminal]

The estimated time from seed to harvest is 53 days, so I'm just going by the lower limit when I say 8 days. But yeah, compared to another grow diary these look very puny.
Not entirely sure what happened, it had pretty good growth up to a week ago, until after I sprinkled diatomaceous earth.
The plant also doesn't smell, at all. It had an odor in vegetative stage and flowering, then disappeared a week ago.
Things seem to point at that diatomaceous earth. Could it have fucked up the pH of my watering, causing the plant to be unable to absorb nutrients?

 

[Onetwothree]

Not too sure on that. I have no experience with the stuff, but I know it's pretty commonly used. You could do a slurry test or test the runoff water to get an idea of the pH of your root zone.

 

[notacriminal]

Ah, yeah I completely forgot to test the runoff pH since I applied the stuff.
Considering I watered yesterday, would it be an issue if I did a flush today?

The only reason I'm suspicious of the diatomaceous earth is the fact that it has an oddly deodorized smell. Smells faintly of some sort of yoghurt. Very weird.

 

[Onetwothree]

If the pH of the root zone is screwy then I don't think flushing would be a bad idea.

 

[notacriminal]

Went to get a little runoff, the pH measured ~6.8. I'm getting real tired of using strips.
Anyway, a couple of the leaves are now looking like this. Am I right in thinking it looks like magnesium deficiency?

 

[notacriminal]

Alright, figured I might as well flush it, despite the pH not being off. Checking up on this this morning it looks exactly as I left it last evening, no discernible difference at all.
Since it's not looking worse, I'm guessing it was an Mg deficiency caused by lockouts due to salt buildup as a result of using baking soda for an impromptu pH U, with the effect perhaps compounded by the late flower yellowing.
Next time I'll mix up a batch of diluted potassium hydroxide.

The buds have already grown a bit and the smell has returned to that pungent odor you'd expect from a plant in full bloom.

It's a bit shitty that I've effectively lost a week of flowering, but eh, live and learn.
I've found a source of cheap fert. nearby, so I'll deem this "household grow" experiment a failure for now and buy some of the good shit for next time.
Thanks for your help, and for giving me a place to voice my concerns.

 

[Fishmaster42]

Those buds are no where near done. when it says 53 days it mean 53 days of flower after that plant has been in veg. your about half way done those buds will get much bigger 2x easy.

 

[notacriminal]

I thought that only applied to photoperiods?
From the breeders own website:
"Flowering time: 5 weeks
Seed to harvest: from 53 to 69 days 8 - 10 weeks "

It started flowering Day 20~21, I'm on Day 46 now, so I'd have about a week's left of flowering. Harvest right before Christmas, smokable by New Year's Eve.

If what you're saying is true, I'd be pretty elated honestly. This is a real low yield if I've ever seen one, but I am a bit worried about misunderstanding the breeder's directions and letting it sit in Flowering for twice the required duration. There's a cutoff point where the trichomes break down and the plant grows stamen in order to pollinate itself, right?

Edit: Ah, crap. Taking another look at the pictures, it seems pretty much all leaves, not just the fan leaves, has gotten just a smidge more pale compared to yesterday. Maybe it just is N deficiency.

 

[Fishmaster42]

Bro low yield is a under statement most people veg for 1 to 2 months. the plant is not big enough to make more than a few grams of dried cured pot. Im not trying to piss you off just help out. get another plant keep it in there when the lights on, move it out when the light offs into a room with light on do this every day and once your done with that plant you are flowering you will have a 3 ft plant to replace it vegged out. then flower again. We are all here for help. If this shit was easy everyone would wake up and become a farmer. keep reading keep the faith. Keep asking questions. Good luck. and your on day 26 of flower. when you relay info talk in days flower.

 

[notacriminal]

Don't worry, I'm getting zero "piss-off" vibes from you ;)

This is an autoflowerer though, not sure if you missed it in the OP. Keeping it in veg isn't an option.
Didn't know that about talking in flower days, but makes sense. Figured I'd count from planting since we're talking autoflowerer.

 

[Fishmaster42]

Im not an expert on whats a auto flower or not, I been growing many diff plants for years and some will show sex under 24 hrs of light. bud they wont start growing huge buds just show sex. I still call that veg until i flip the lights to 12/12. More root more fruit is a favorite quote from a old redneck grower back home. makes it simple bigger your root ball more herbs you get. So the more light you put on them in veg and the longer you wait to flip the light to 12 /12 bigger she gets.

 

[notacriminal]

Alright, well, autoflowerers go into flowering after a period of time as opposed to changing photoperiods. They're bred from russian Ruderalis which has this behavior due to the rapidly falling temperatures during the later Summer months. If they had to wait for light to fall to 12/12 they'd succumb to frost, so they adapted and instead have a time-delayed mechanism that starts when they're germinated. It's some fascinating stuff, really.

Either way, they don't care about 12/12 and are going to flower regardless. In fact, they grow better if you don't change the light schedule at all.

 

[Fishmaster42]

sounds like a good plant for a DWC setup under 24 hrs of light. There must be something these guys are doing to keep it from flowering a little bit otherwise they would all be that same size and wouldnt be worth growing. Well Lets see how she turns out. Ill be waiting for your next pictures.

 

[notacriminal]

I think it's down to the genetics of the individual plant. The conditions of the grow probably has something to say, too.
I wish I could do hydro, it's some serious sci-fi shit lmao.

I'll put up some pictures in a week's time. Hopefully she'll catch up a bit. At the very latest I'll be pulling her down the 23rd, both since I'll be out of town a few days and also because I don't think it'd be worth spending more time and effort on this. I'd rather get started on a proper grow with some good fertilizers.
But hey, thanks for the interest in helping!

 

[notacriminal]

Haha, oh man. This plant is definitely not feeling well.
I have no clue what's causing the dark edges on the leaves, but there's definitely some Mag/N def going on.
The trichomes are pretty much all milky on the nugs I inspected, so this is going down tomorrow.