Complete soil renewal ?

I have a white in revegg, the soil has gone to shit and the plant is really suffering. the question i have is what is the best way to do this?
i have thought filling a washtub half full with water and rinsing not all but 3/4 of the soil out then blend new soil into the roots and mabe give it a root trim ? never had to do this so i really dont wanna mess up

Normally you either transplant up, leaving the existing soil intact, or you apply a fertilizer. You don't need to remove the old soil, unless it's been over fertilized and your doing a last ditch effort to save the plant. And usually that's just when they're young.

i read in one of the grow books about root trimming but i cant remember what it said to do

I would only cut roots if they were rotted (usually brown or black looking). If your just trying to keep the plant small, fabric grow bags or air pots work really good. It's easier and less traumatic for the plants then cutting them.

Try a good flush before you do anything more radical. At the very least a flushing will rinse out any accumulated nutes
and let you proceed with a relatively blank slate. I don't believe in transplanting full-grown plants unless it's an emergency.
It is too easy to break branches when tp'ing older plants as they are more rigid and not as supple.

Try this instead -- Use an exacto knife and cut off the bottom of the pot the plant is in. Just slice it off clean. Don't worry
about hurting the roots. Set up a second larger pot but only fill it 2/3 full. Scrape a bowl in the middle of the new dirt and
set the roots right in the bowl. Set it there old pot and all. Pat new soil around the old pot until you can't see the old pot.
Roots will grow straight down into the new soil and grow roots there. Plus the plant is much less stressed this way than a
regular transplanting.

Good luck, BigSteve.

If a plant has been mostly harvested then it's root mass is oversized for the plant. If you are going to the efforts to reveg the plant then I would remove the plant from its current home, break up the root ball as much as possible and cut it down in size more relative to how much of the plant is going to be above ground. Then replant it into some fresh new soil.

thats almost what i did lol i did break up the ball, shook alot of dirt from it, then trimmed the roots that was about 3 foot long, then i gently massaged dirt back into the roots as i put it in its new pot of soil. watered her very good. hope she lives, if not ill germ hawaian snow seeds that came from a herm lol

reason for all this is.....soil was pure shit. used up, very poor ph. salt buildup. the plant wouldnt grow any more