Meyers do not come true from seed. I had two that I started from seed. They grew really well for a year and then died. I have no idea why.

The reason your seedling "Meyer" is producing thorns,is becuse it is a immature tree. Almost all immature citrus trees product thorns until they becme mature.

The reason your "Meyer" is producing thorns is because it is a seedling; virtually all seed grown citrus have thorns. At any rate, it is highly unlikely that your seedling will be a Meyer; it may be something similar, or it may be something entirely different (Meyers are a mix of orange, mandarin, and lemon). I once planted 500 Meyer seeds and got a whole range of different size/shape/etc. trees; but not one of them produced its first flower in 5 years; so I pulled them.

My 7 foot grafted Lemon Meyer is loaded with very sharp skinny thorns..Just ask my hand and arms trimming it down the other day..God, they hurt.

Thanks for all the comments! I started the seed about 2 years ago. looking at my nurssey-bought tree, i cant find a graft knob. Isnt that usually down near the soil line? Thats why I ask if if produces on it's own. Can i do my own graft? The trunk is getting pretty sturdy.

Meyers are often grown from cuttings to be sold in the north. Your nursery-bought plant may not even be grafted.