Chang Hua Man Royal Project

Chang Hua Man Royal Project is a 250-rai working demonstration farm in Tha Yang district, a short drive inland from Cha-am. King Bhumibol Adulyadej bought the land in 2008 and 2009 with his own funds after being given local sweet potatoes that he had weighed on an antique scale at Klai Kangwon Palace — “chang hua man” means roughly “weighing the tuber,” and the name stuck. It’s free to enter, open daily from 08:00 to 16:00, and unlike many royal-project sites this one is set up with visitors in mind rather than being purely a research station.

A free shuttle tram loops the grounds roughly every 30 minutes between 08:30 and 15:30, which matters — 250 rai is too much ground to cover comfortably on foot in Phetchaburi’s heat. The tram stops at wind turbines used to demonstrate renewable power generation, crop trial plots (rice varieties, jatropha, rose apple, asparagus, and rotating vegetable beds), a composting operation, and pens holding the farm’s dairy cattle. None of it is dressed up for tourists — the crops are grown for actual agricultural research into what performs well in this dry corner of Phetchaburi, and the farm shop near the entrance sells whatever the plots are producing that season, from vegetables to dairy.

Insider Tip: Go in the morning. The tram runs a fixed loop rather than an on-demand service, staff are more available earlier in the day, and by early afternoon the open plots between stops get genuinely hot to walk across.

Watch out: This is agricultural infrastructure, not a landscaped park — expect functional demonstration plots and working sheds rather than manicured gardens. If you’re picturing a botanical garden, recalibrate; the interest here is in what’s being grown and why, not ornamental design.

Public transport doesn’t reach the site. It works best as a stop on a self-driven or tour-arranged Phetchaburi/Cha-am day rather than a standalone destination, and it pairs naturally with Phra Ram Ratchaniwet or Phetchaburi’s other royal-initiative sites for travellers interested in the monarchy’s rural development work.

Other royal-initiative sites worth combining with a visit include The Laem Phak Bia Royal Project and the Royal Sea Farming and Aquaculture Demonstration Project, both elsewhere in Phetchaburi province.