Since you're just getting started, there's not a whole lot to say. The others have pointed out the image issues (the background is 2.8mb).
Objective: Centered content text makes for a difficult read. We're just not conditioned to read this way.
Subjective: I don't think the grass background is working well. It's a bit dark, a bit overwhelming, and it doesn't create any real definition for your banner image.
You'll want to see how your site looks in the three main browsers. In Chrome, your menu's right side is approximately 5px short of the banner image. In IE and Firefox, it's fine.
If you haven't done so, read up on the Beginners SEO Guides and understand how to effective write page TITLEs, etc.
Get your local info on there. Contact info (NAP), service areas, etc.
a guy who knows both the lawn business and web strategy