Is this heat burn or nute burn or dehydration? Please advise..

Quick background:

I haven't fertilized my plants yet, however it is miracle grow soil, and has 3 month long acting fertilizer in it. The plants have been in this new soil for 8 days, only 1 plant is showing this problem however.

This is ALSO the same plant I topped yesterday because I burnt the top new baby leaves. However, the leaves under it (the ones that are yellow today) were green last night before going to bed. Than this morning, they were yellow.

Can yellowing of the leaves underneath the top leaves, happen hours later after your burn the top leaves? I thought a burn was instant. They touch the bulb and burn. These were the leafs underneath, and it didn't show till this morning.

I just want to make sure this isn't the delayed release fertilizer in the soil causing this. But I thought a burn was suppose to happen right away. Which one do you think it is? Sorry if this is confusing.

And why could the tips of my second plant be curling all a sudden today? The temp is 74. I watered these plants everyday for the first 4 weeks (smaller amounts though only like 16oz per plants). Their leaves were fine. I read here to water every other day, and started doing that about a week ago. You don't think the plants are dehydrated after a week of changing watering? Hence the curling leaves? I just have like 3 different things it seems it could be. But I've explained it the clearest I can and have 2 pics. One of the plants I topped like I said (burned the leaves above it), the other plant the only thing that has changed was I dropped watering to every other day about a week ago. I'm just trying to figure out if I should be doing something different from the leaves showing all this stress all a sudden.

Thanks!

Ok well looking at various pictures online the yellow edges definitely seems more like light burn than any burn from the extended release nutes. It also seems like when theres a nute deficiency the marks happen all over the leaves, and not just the edges, so I'm pretty confident it was only a burn.

As far as why the leaves are droopy out of nowhere on the second plant, I'm still not sure why. The only thing I can assume is the soil is too dense, and I think at this point I need a lighter soil. I knew when I bought it it was too heavy, but I thought it would help the roots grow stronger thus creating more growth. But it definitely seems pot doesnt like dense soil. I put a little bit of peroxide in the soil, and I'm gonna get a lighter soil to do another transplant for all of them. It seems like every since I put them in the soil the leaves lost rigidness, so it has to be the soil thats causing the drooping.

Change the soil soon. The MG pre-mixed nutrients are too strong for the small seedling. This is a Nitrogen burn. That is what is causing the droopy plants too. The leaves on these plants will probably look like the damaged ones soon. The tips and edges are burned now, but soon the whole leaf will show dessication. Also when you transplant if you have them dark pots grow better than white. White can let light in and cause algae growth on the soil ball and the inside edge of the pot.

Part of the droopy look could be because the soil does not have enough drainage and is staying too wet.

I'd invest in a bag of Perlite to mix with your new soil. Perlite will retain some water, but will mostly help with drainage and getting O2 to your roots.

Also, I'd make sure to add either Cal-Mag or 1/4 tsp of Epsom Salt (Magnesium Sulfate) per gallon of water. I nearly drove myself mad trying to figure out why my plants were drooping before figuring out it was a Mag deficiency. As usual, always check that PH bro.

Good luck on your grow !

You bought the wrong soil buddy....... MG makes two products, one is a soil and the other is a peat based potting mix with perlite. You should have bought the mix. The MG soil holds a TON of water, too much for pot. It's also very dense. And any time release MG is a poor choice because later on when you start to flower, the plants will continue to get a big shot of N because of the slow release of nutes (for 3 months). It could delay flowering. Lastly, it will also burn younger plants, although more mature plants in veg will do very well.

Oh, and like the guy above said, you need some pots that will block out light. Go for the ones with drainage holes in the bottom and get a runoff try to go underneath.

Is it possible to change nearly flowering plants into new soil? and how do you do it??

Lose the tin foil. IT creates heat spots in your grow room. use mylar

WOW I can't believe all this advice this is really excellent. I didn't really wanna makes any moves till I got some responses but I'm running to lowes right now to get some new soil. I can't let my babies torture like that the other plants are actually showing signs of stress now too. Like the same on that one plant. People say "pots a weed and will grow in anything" which is kind of what justified me buying nonrecommended soil, but it really was just a dumb move. Going to get it right now and I'm curious where does on get "mylar" from? Thanks guys!

Ok lowes officially sucks. It pisses me off that EVERY soil they sell has the extended release fertilizer crap. Not only that they don't sell perlite in the store by me. There was only 1 type of potting mix and it was organic miracle grow potting mix. So I got that instead. I figure compared to the miracle grow extended release TOP SOIL, it should make a huge difference. Than I'm gonna have to ph and make sure everythings nice and balanced. But the organic potting soil shouldn't create a nitrogen burn right? Just want to make sure. You can tell the soil is light and airy compared to the heavy soil I was using before. So I think that alone should help the plants hopefully.

Here's the best hint anyone will ever give you......STOP SHOPPING AT LOWES OR HOME DEPOT. Go to a GOOD local garden center nearby. Most will sell a couple of different potting soil mixes, i.e. Pro-mix (east coast), Sunshine mix (west coast) or any number of other brands. Read the package well and make sure it is spagnum based, has lime and perlite in it and is somewhat pH neutral. It will tell you what it's good for. IT SHOULD SAY for"good for potted plants that like a lighter mix". Time release fertilizer mixes are a no-no- they are better for outside grows. Transplant your plants into the new soil, with a dose of B1 to ease transplant shock. A couple days you'll be a new man.........