Brownish spots on my spearmint plant

[Qb_Master]

Hey guys, newbie here (both to gardening and to this forum)

I have a spearmint plant I'm growing, which recently has developed brownish marks on some of the leaves. A similar thing happened to some morning glories I was trying to grow last year, which ultimately died (I think due to weather.)

Can anybody tell me what might be going on, and what I should do about it?

Please see attached pics:

[applestar]

Wow they are relentless! I believe these are works of leaf miners. The fly larvae burrow between the upper and lower layers of the leaf. If you look closely, you will see a trail and the maggot at the end of it. It's possible to crush inside the leaf with your fingers if a plant only has a few leaves, but generally, it's best to clip off entire or partial affected portion of the leaf. This way it's easier to spot further infestations.

I didn't know they infested mint, too ??? Hmm... On second look, I think this is NOT mint but a pigweed/amaranth. Does it smell minty?

[Qb_Master]

On that note, it sure does look like pigweed o.O And definitely does not have a minty odor.

Wonder how that managed to happen. I know the seeds I had were spearmint. This is in a raised pot with fresh soil over concrete..so I'm not sure how pigweed could've gotten in there.

But yeah, told ya I'm a newbie, so must be doing something/things wrong :p

[applestar]

It's possible some of those tiny other seedlings are the mint. Pigweed sprouts quickly when exposed to the light (the seeds burst out of the mature dried seed pods) but mint takes a while to germinate. Take out the pigweed by cutting it off at (or just below) soil level so as not to disturb the soil, and keep the pot watered for a while longer and see. (It's possible the pigweed is suppressing growth of the others).

Once the little ones are big enough to pinch, you'll be able to smell them.

[Qb_Master]

Alright, I'll do that. Thanks for the help!

After surveying the surrounding area, looks like there is some pigweed that has managed to sneak through cracks in the surrounding concrete. I had been cutting it back, but didn't think it would find its way into my pot. I'll attempt to clear that out to prevent this from happening again, and be a bit more informed as to what exactly I'm growing