First grow- Help me guess deficiencies?

[Jcragor]

Im growing grandaddy purple auto flowers and I’m on day 55. They all started flowering on like week 3 so I’m guessing maybe I’m starting to wind down. They all seem to have different deficiency(or toxicity) indicators going so I’m looking for some help. I’ve included pictures of the oldest bud, newest bud, and pictures of stress signs the plant has. The second plant also has dark purple stems while the other ones don’t really. On the third plant I’m wondering if the buds on the top are damaged/burnt or if the buds just gradually turn darker like that(it is grandaddy purple after all and this one started flowering earlier than the rest). Also curious if I should start flushing or anything at this point or continue with the bloom nutrients. Thanks in advance! Any questions please ask.

Edit: As far as a feeding schedule I’ve just been checking weight of the pot, and checking water up to my first knuckle to know when to water again. It’s generally been about 3 days. Im using calimagic(200-250 ppm), GH floratrio, but have had issues with nitrogen toxicity so I’ve been skimping on the micro and gro to try not to add more. I’ve still been adding the bloom nutrients at about 200ppm or so per feeding. The runoff is at around 1100 for all of the plants, it was higher previously which is why I’ve been adding lower levels of nutrients(I think realistically I wasn’t getting enough runoff and was drying salts in my soil for a while earlier in the grow). The two larger plants(2 and 4) were started in a solo cup in coco coir, but was not having luck with it so transplanted into fox farms happy frog when I transplanted the plants. The other two (1 and 3) have always been in happy frog. Since transplanting in soil I would say the ph has always been between 6.2-6.7. That’s one thing I’m curious about, if the ph is good for the part of the root system in soil, but isnt able to grab calmag as well with that ph in the coco coir part of the root system. The temp is around 75 with the lights on, humidity at 45-50%, light is a sf4000 at 100%, 18 inches from the top of the plants. I’ve got two small fans oscillating on the plants and an exhaust fan that goes for 8 minutes every 15 minutes

[MeowMeow]

Overall, they actually look pretty nice.

Some thoughts:

• PH too high or too low - They look like they have some kind of a deficiency, and the pH is the most common reason to see nutrient deficiencies. You mentioned you're checking the pH, which is great. But are you checking the runoff water or just the input water? Even if you're putting it in at 6.5 pH, if it's coming out a 7 or 5 or something, you know that the issues is something in the soil affecting the pH. The nutrients change chemical form when the pH is too high or low, and the plant has trouble absorbing those forms.
• Re-vegging - Is there possibly a light leak, or the electrical timer isn't consistently turning off for 12 hours a day? Is there some way they might be getting dark during their night period? They almost look like the first stage of re-vegging. I noticed the top fan leaves look like they have only 3 points, instead of 7+. Too few points per leaf can be the first sign of revegging, or signs of other leaf stress like changing light schedules. I also seen some single-point leaves on the buds, which is another possible sign. However, you don't have the signs of full reveg like smooth leaf edges. If the start of re-vegging is the case, the best thing to do is ensure they get 12 solid hours of dark every day with no peeking on the plants during their dark period, equipment lights blinking inside the grow space, etc. That should help them stay firmly in the flowering stage
• Nutrients - you mentioned you're using Calmagic and the GH Flora trio but were having an N toxicity, so you started giving less. However, you don't want to alter the ratios of your nutrients by giving just some of the bottles but not all. It's better to mix the right nutrient ratios, but just less overall. So like instead of doing 1/2 what's on the side of the bottle, do 1/4 or even 1/8. I doubt that's causing this, but just a thought. Happy Frog is a very low nutrient soil, and at this point they've likely used up all the nutrients in it, so they're totally reliant on the nutrients you give them.

Just curious, why do you have the exhaust not going 24/7? Would it get to cold in there? Generally, more fresh air is better, and if you have a carbon filter, it won't work well if the fan isn't always running.

You're doing a great job. It's growers that stay on top of things at the first sign of issues that end up becoming the best growers!