Looks like the sort of thing I've been pulling from my flowerbed today. But why are you upset with MiracleGro? It's just fertilizer. See how robust and healthy your weeds look? It takes fertilizer to grow noxious weeds so well.

We are both in Florida. Ours are tropical weeds, and they thrive in our poor, sandy soils. Imagine if we give them fertilizer!

It is not too late to go buy more seeds and start them in starter pots on the kitchen window. Inside. When they are a few inches high, you may transfer them ot larger containers and with mulch carefully applied, you will be weed free. The intentioanl plants will appreciate the mulch, as it holds in moisture, breaks down into fertilizer, and eleiminates all competition.

Happy growing!

Are you referring to MG potting soil? It's extremely unlikely that a bag of that had viable weed seeds in it. They expose that material to high temperatures to kill weed seeds, fungus, bug eggs, etc... More likely would be the possibility that (if they aren't the seeds you put in the pot) they were blown into the pots by the wind, or from birds. That's how most weeds get spread around.

It sounds like you planted more than 1 kind of seed. Do you have a "list of choices"? At least narrow it down to food plants vs. flowers? Many plants are tricky to ID until they get more mature. The first set of greenery that comes out of a sprouted seed is usually a pair of cotyledons, not really leaves. Many plants have leaves that change shape and size as the plant matures, making ID tricky for a lot of baby plants.

One good thing about having a NOID plant in a pot instead of in the ground is that if you do have to wait until it flowers to know what it is, you don't risk having some big taproot or tangle of sneaky rhizomes to shovel up if turns out to be a bad boy.

The Miracle Grow potting mixes I have looked at are simply very expensive peat moss mixes with some other stuff, such as "slow release" fertilizers, added. I have had the same results using my compost in my containers that I get with that material.
"Weed" seeds can be blown into containers by the wind, deposited there by birds flying over, or maybe even planted by squirrels or other wee critters. It is not very likely they would be in the potting mix until that mix is exposed to the elements.
If this is a plant you do not want growing where you do not want it to grow it is a "weed" and you can simply pull it out of the pot, or cut the stem at the soil line. Too many plants look very similar at the seedling stage.