One common question that always comes to the mind of expatriates has been the limited ownership of property in Thailand. You may note that there are restrictions to ownership. Basically, you would need to sign a document that you have no claim on the land which your wife is buying in her name. This document will be filed with the Land Department in Thailand. For years a common perception has been that a Thai woman may only buy 10 Rai of land however this is not the case.
There is no limit as to how large the land is, however as stated for her to own land, you, being her husband, must sign an affidavit at the Provincial Land Office guaranteeing that she is not using communal property acquired after marriage to buy the land. When buying property in the name of your wife always speak to an attorney beforehand with regards to her rights as well as yours should the marriage not last as long as the land. Preparing for the worst is much better than sitting in a storm later when you have no options are have not planned properly.