My neighbor called me to tell me that they have had a garden they've maintained for 25 years, that juts into my property by 10 feet. My lot is vacant and I purchased it last year from a developer. It was originally owned by the a water company in the state, but I am not sure if it is a state entity or private. The water company sold it to deveolper #1 in 1998 who then sold it to developer #2 in 2005. I bought it from developer #2 in 2008.

We have decided to build a house on the land and construction has begun (2 weeks ago). The enigineer and builder notified me that the neighbor's garden is on my property. In order to get approval to build the land, we needed to get zoning board approval for a height variance. There were several hearings and the neighbors knew about them, but never showed up to any of them to dispute the property line. The survey of my land is also recent (1 year old) and clearly shows the property line.

My question is how do I protect my property? What should I do?

If you don't have a problem with them maintaining their garden, and merely want to protect yourself from having them take ownership of that property, then send them a letter by certified mail giving them your permission for them to maintain their garden on your property. One of the requirements of adverse possession is that they use the property without your consent. If you give your consent then they can't fulfill that requirement.