The "weed" names don't seem to be as popular as the "canna" and "cannabis" names.
Also, when using "automatic" to combine with another word, it generally seems to be more preferable to go with "matic" instead of "omatic" (i.e. Weedmatic may be the better choice, but alas... registered).
On top of that, Namebio doesn't have any recorded sales in the past couple years for a "weed" brandable that isn't strictly weed+word. So perhaps the market isn't into the word combos quite yet.
I'd be happy to sell it between $100-$200, but maybe if you hang onto it for a few years it'll become more desirable.