The garden is truly world-class and you will not be disappointed if you decide to visit it.
When you arrive at Queen Sirikit Botanical Garden you pay the entrance fee just as you enter close to the road. Then you have to get up the mountain and to the back of the garden. There is as well a bus going there.
On top of the mountain, you find a restaurant, a souvenir shop, a flower shop, and all the greenhouses.
Each of the greenhouses is dedicated to one kind of plants like there is, for example, one for orchids and ferns, one for cactus, one for bromeliads, you also find a big greenhouse there is made into a jungle house. I think there are about 6 or 8 greenhouses all together.
A research center is also present in Queen Sirikit Botanical Garden. It has a good working relationship with other botanical gardens around the world.
The garden is very big and has a lot of different things to look at. I spend 4 hours in the gardens and I did not have time to see it all. Of course, you can run around the park in less time and see the most interesting places. But if you will take the time to see the different things you need to allocate at least a half day.