At a complete loss
I started my vegetable garden with a 50/50 mix of soil (sandy soil, we're in florida) from my land and compost that were in bags. I used about 5 bags of earth gro and 4 bags of black kow.I mixed it well and waited a week before planting my seedlings which I soaked to jumpstart germination. All was well until a week ago. I started to do alot of research but there are so many issues that I can't narrow it down to one. I need some help.
1) The plants began to get yellow spots on the leaves, I looked under them with a magnifying glass for mites (yes I looked under each one took me 3 hrs!) I read somewhere that 9 parts water to milk is good for the plants immune system so I sprayed them with that hoping it would help them out. Well it didn't.
2) I stopped watering for about 4 days, figured maybe I was drowning them. I was watering them everyday up until that point for about 5 minutes a day. Anyway, they looked thirsty so I watered heavy one day, two days after that I see mushrooms, a set of them that were red and a set of them that wither away almost immediately when the sun comes out.
3) Today some of my plants have bottom leaves that are completely yellow. I read that this could be due to lack of nitrogen. Confused cause I fertilized these at one point with Dolomite.
4)My dh told me yesterday that my corn was doing well had red stems. I was immediately alarmed because I read somewhere that red stems was a bad sign, I noticed that my cabbage and collard plants have red stems, is this normal or am I paranoid?
I'm a new gardener btw, I'm about give up, lol. I've been researching this but all of these symptoms are throwing me for a loop and I'm afraid of killing my garden by trying something else.
Thanks for any help in advance.