Does anyone know what plant this it? I planted a pack of spearmint seeds i bought online and this plant grew along with my mint plants. No idea what plant it could be, would like to know how to properly care for it.
A good rule of thumb is that if an unknown plant grows from a packet of seeds of another plant species, that unknown plant is almost certainly a weed. Don't try to keep it alive. Kill it. Seal it in a bag and put it in the garbage. Or kill and sterilize it in your oven, then compost it.
I mean, feel free to try to identify it first. But definitely don't let it go to seed.