What's wrong with these plants?

Hello all, this is my first grow and i'm having some problems.

All my plants seem to have the same problem, mainly with the lower leaves yellow and browning, and the leaves dropping.

The biggest one is about 3 months old. The 4 in the brown pots are 18 days old, and the 2 little ones are about 9 days old.

Temp is 75-80, humidity is 35-50%. I'm not sure why the humidity varies so much, but it does. It was steady at 20%, then I got a small humidifier and now it varies between 35% to 50%.

I have only fertilized them 1 time with 20-20-20, and that was last week. How often should I fertilize them? Every other watering? I water them about twice a week when the soil is dry about an inch below the surface.

When i water I just pour the water in until it starts to drip from the bottom of the pot, is that the correct way to do it?

Any help you can provide would be greatly appreciated! Thanks in advance!

Edit: I forgot to mention the PH is around 6, and I wanted to add a picture of the hidden bookshelf style closet door I just finished building. It turned out pretty sweet!

#1 you probably need better lights
#2 your plants require 20-10-12 for veg, and 5-20-12 for flowering.. it sounds like your getting your shit from home depot.. if you want to grow regs/mids, dont use any nutes and save yourself some money
i water my plants around 2-3 times a week, i use heavy nutes(1-2 tbsp) once a week.... and yes your watering the right way

Those plants are too small to be needing any ferts in that soil bro, and you're over-watering.

looks like overwatering or lack of lights

Also watch it if it's MG soil every time you water you are giving it nutes I made this same mistake recently

Thanks for the replies. I only water when the soil is dry 1 inch below the surface, which is what I read to do, so I didn't think i'm over watering. I'm using (4) 4' Fluorescent bulbs as my lights for veg, and I have a 400 watt HPS to use for flowering. My soil says it provides food for 2 weeks, so that is why I started fertilizing last week. Should I stop and wait a little longer?

Cyndric said:

Thanks for the replies. I only water when the soil is dry 1 inch below the surface, which is what I read to do, so I didn't think i'm over watering. I'm using (4) 4' Fluorescent bulbs as my lights for veg, and I have a 400 watt HPS to use for flowering. My soil says it provides food for 2 weeks, so that is why I started fertilizing last week. Should I stop and wait a little longer?

Click to expand...

If you knew anything you wouldn't be asking for help. Since you did, and I've replied, let's just assume you need the input. I also said you don't need to be feeding, and you ask if you should stop feeding.

Overwatering!!!!!

Yeah stop feeding/watering I recently flushed my plants and are letting them dry since then they have all grown new leaves.
they we're at a total standstill on growing cause of my overwatering

i just wanna say...
yes, it could be from feeding or over watering. however, bottom leaves do die sometimes to grow new leaves...
What lighting are you using for veg right now? how many watts?

Ok, I will not water them as much and i will stop feeding them. My 4 fluorescents are 42 or 48 watts each. I was planning to wait until flowering to hook up the 400 watt high bay I have (I actually have 12 of them if anyone wants to buy some, let me know ).

Thanks for the help!

Holly Crap! What happened!

I've been gone for 7 days and in that time something has happened to my oldest plant...

The first picture is from 10 days ago (pot is different because I replanted after taking first picture), the others are from today! The leaves... where'd they go! There is only 1 big leaf left! The leaf had 3 pedals on it, now there's only 2. The 3rd one looks like it was... eat off? All the other big leaves are gone, their stems are still there but the leaves aren't, and they aren't in the pot as they would be if they fell off or something.

There are spots all over of what looks like white bubbles, but under a microscope looks like sugar crystals.

The last picture is of one of my 4 younger plants which all look good, all in the same grow room under the same conditions.

I had a friend come over on the 4th day I was gone to see if they needed watering, but he said they didn't. I called him today to see if he did anything and he said he didn't do anything to any of the plants.

What could have happened?

Anyone have any ideas?

I'm mainly concerned about the white stuff as I don't want it to transfer to my other plants if it's something bad.