High pH is killing my plants!

My plants are 7 weeks old. 1 week ago, the tallest plants was getting a little chlorotic, so I treated with epsom salt. A few days later I saw that the bottom leaves were yellowing on a couple of plants, so I tested the pH of the soil and our tap water and it was 7.5

2 days ago, I flushed the tallest plant with vinegar water to bring the ph down. The next day it looked very droopy. This morning, I saw that the main stem folded over and the leaves were pretty dead. Not sure if the vinegar water was too strong and caused root shock?
Def not root rot, as I inspected the roots and they were nice and white.

Is this a pH issue? What is an appropriate way to flush without killing your plant?

The other plants look fairly healthy, except for yellowing of lower leaves and some brown spots on fan leaves.

Please help, they are ready to flower and I'm not sure what is the best thing to do.

In order to properly flush you have to do the following. Place the pot with the plant in the tub or garden or any place you don't mind getting very wet, remove the dish under the pot and just start pouring the water. The water starts coming out through the holes in the bottom of the pot taking with it all the bad stuff you want to eliminate from your soil.

If your leaves looked droopy, it's a sign of overwatering. Did you let all the water run out of the pot?

The best way to fix a pH problem is to go down to your local pet shop and ask for pH-down or pH-up. These are usually used to fix pH problems in aquarium water without harming fish, so are natural and safe for your roots. Vinegar can sometimes harm the roots.

hm, do you think it was the vinegar that killed the plant? I looked through the roots when I dumped out the soil and they looked white, didn't smell or feel slimy, but they were really thin and long. The main stem just folded over and went limp (as did the leaves).

I guess, I thought I didn't need to buy pH down, that I could do it with lemon or vinegar, but I think I'll taken your advice.

Do you think the leaves are just going to keep dying as we go up the plant? Does this explain the brown spots and coppery spots even though I've been feeding?

I'm really excited because this is my first grow and I've got some Willie Nelsons and a couple Papayas to look forward to harvesting soon. I just hope they make it that far :fingers crossed:

Thanks so much for your help

As I said, the droopyness could be from exces water trapped in the soil, so you should just not water anytime soon and see if the situation fixes itself.

At 7 weeks it's normal for 2-4 bottom leaves to start falling off. But seeing that you had a high pH, you could be experiencing a nute lockout causing a deficiency. I suggest you fix the pH problem fast and get back to feeding.

Lemon juice is also pretty good, but takes surprisingly alot of lemons (6-10) to actually cause any change in pH. If you've got a large pot, it's a waste of time, energy and lemons.

the spots on the leaves are nute burn

Spots caused by nute burn usually start appearing on the tips forst, then move towards the stem. In this case, it's just the deficinecy causing local necrosis in the leaves causing the spots.