3 weeks flower...? don't fuck with it. the latest I will transplant is 2 weeks flower and even then I feel it is often detrimental...1 week flower is okay, but still not good. best to transplant a few weeks before flower to give the lady some time to settle into her new home. at 3 weeks you will probably just shock her and reduce budset.
that being said, if you have soil that just finished cycling (what do you mean by this?), you could apply a topdress of the new soil and see if that helps. As a general rule of thumb for most issues, I would recommend a topdress of EWC, kelp, crab, and neem meal if you have it. almost any topdressing will take a week or two to be metabolized by the food web in the soil and reach your plants, so keep this in mind...at 3 weeks flower you are pushing it on the practicality of the topdress.
what issues are you having exactly? it wasn't clear from your post...
regardless, the topdress will provide almost everything your plant needs once it becomes available...can't really hurt
either that, or buy a whole case of perrier and flush, flush, flush! one case (12 bottles) per plant should be good IMO
Click my sig if you don't mind bro, and look at the last page or so and you can see pics the latest pics and maybe that'll help you visualize what I'm about to say.
But I'm not having any issues, I just want to transplant my Critical Jack and a bag seed which, is obviously Sativa dominant to bigger pots.
I just got some smart pots and figured they'd be the perfect candidates.
They've been on 12/12 all but a week of their existence and they're now 41 days from seed, and appear to be about two weeks into flowering.
I did a lot of reading and come to the conclusion that I'll transplant them tomorrow. They're all in a under a gallon of soil currently and want to up them to the 3gal smart pots.
I'm growing in grow bags so I can cut them off without disturbing the root mass at all.
And when I say I have soil that just finished cycling..I mean cooking.
I mixed the batch up a month ago today, so it's ready for use now.
But I've got a lot going on in my garden ATM so you wouldn't be able to understand without seeing.
I don't have any one prob tho. Other than my recent OD of molasses. I up'd the dosage of molaases in my tea to 3tbsp per gal and my plants didn't like it AT ALL. They yellowed progressively from the bottom for a couple day, I did a semi flush I guess as I just gave them an extra half gal of H20, ad I top dressed them with EWC, mycos, and Kelp. Don't have crab or neem atm.
BUT....The OD of Mollases also showed up on the leaves of one of my plants in the form of necrosis.
Would seem like an excess of sugars would show up in the leaves right away given the photosynthesis process...
Besides...Upping the molasses was the only thing I did different last week, so its without a doubt the cause of my issues..
I figure adding the ewcs will help things out and I'll add a layer of the new soil with the next watering to help things even more..
And perrier? what?