I planted this cacti a little over a year ago. It's about the size of a toothpick now, but i still don't know what kind it is? It's starting to grow small "threads" by the thorns, and there are running "darker green lines" along it vertically. Also, now it's looking a little.. "soft/moist" on the (left on the picture) side, and some of the thorns on the bottom looks soft. It stands in my window all day, so it gets all the summer sun. Is it overwatering or what is wrong?
It does look like it might be suffering from overwatering. Keep the soil on the dry side, only water again when the soil is completely dry.
Too small to be reliably identified yet. Maybe Echinocereus? Cactus seedlings can grow too tall sometimes, but they usually broaden and look more normal when they grow older. Yours is definitely not a hopeless case yet, but if you can, try to move it to a cooler but still well-lit spot, the combination of high temperature 24 hours a day and (relatively) low light in windowsills promotes elongated growth.
