@Rangervegas I don't have season yet. And I didn't do gardening as full time project before so some things below may be wrong due to spending more attention to it.
For my test gardens : it takes longer to grow things. Indoor seems worse, but I may be wrong. If you want the first step of freelance botanist, plant 10 things and water them immediately. if you pass the 5am mark, they'll be marked as watered.
There are no harvestables in festivals planters. It's maybe in purpose given the now very hight value of flowers(love festival) and dragonfruits(spices). I think you can take cuttings, but I've no save with a level 5 gardener yet.
I found a dragonfruit in the middle fishing spot in the north of willow spring park, they're worth 250 simoleon at the lowest stage. I fished grenades at a few other places and found them in the City living produce stall, and they're worth a lot too. So fshing is a good starter. blueberries fell at 3 instead of 16 simoleons....
You can't study plants before level 2 I think, and not fertilise until level 3, so maybe spending a moment in willow creek's library studying the first levels of gardening while you have the flowers around grow enough to harvested may be helping. I feel like running around harvesting doesn't give as much experiences as before.
Fishing is needed as you'll need large fish to upgrade your plant quality. On well tended plants, one large fish allowed a plant to be evolvable immediately, when small dog poop and small fish were only bumping the evolution bar a bit. I'm not sure plants will evolve without fertiliser.