Make that Southeast Asian for that matter, since Thai is only one manifestation of these wonderful cuisines! For the most part, the plants I've included are suitable for growing in warm climates such as zones 8-11, but you're only really limited in your enthusiasm. Regardless of where you live, put a tropical spin on a plain jane herb garden, and give your cooking a kick!
Lemongrass in the garden.
An important element of Southeast Asian cooking is the harmonious union of sweet, sour, salty and hot flavors, and sweet elements like fruit are even used like spices to impart a tangy or sweet note to dishes. This post is about spices, but if you want to try growing some fruits for thai cooking, try lychee, rambutan, pitaya (dragonfruit), pomelo, tamarind and bananas. You can even use the flower of the banana as a vegetable!
"Kung Pao" Chili in the garden.
First, lets start with the plants that provide heat to our dishes, moving down to the sweet end of the spectrum. Unless you live in a totally tropical climate, black pepper is out of the question since the species of peperomia it comes from is not cold tolerant in the least.. That's okay though, since its the most common spice out there. Its also interesting to note that northern regions prefer peppercorns over chilies to add heat to their dishes, likely out of necessity. Moving on...
Chili PeppersThe hotter the better! Even if you don't like your food too spicy, peppers are great for balancing the other flavors in a dish to make it exciting and harmonious. Pictured to the left is "Kung Pao", and other varieties include the "Bird's Eye Chilies" like the appropriately named "Thai Hot", which are just slightly cooler on the Scoville scale than the Habanero. The habanero makes an appropriate substitute, since its much more common at the grocery stores. You can get away with using just one or a few slices of the habanero in a dish, so don't overdo it!
You can grow them much like their relatives, the tomatoes. Give them full sun, good water and protect from frost. Try growing them in containers and bring them in on cold nights!
GingerZingiber Officinale is in the same genus as the ornamental shampoo ginger, and also related to other gingers in the garden. Ginger adds a pungent, nutty flavor to food, relieves nausea, and makes a wonderful tea.
Grow in full sun to part shade, well drained soil, and keep the soil moist. You can actually plant the roots you get at the grocery store.
ShallotsThai shallots are more of a pinkish color than the one pictured, and have a stronger flavor. However, common store bought shallots work just fine and seem to be a nice middle ground between garlic and onions. Grow as you would onions, and in warm areas like Florida these are best grown in the cool season.
LemongrassRelated to citronella, this incredibly useful herb adds an aromatic citrus quality to curries and soups but without the tartness of a lime or lemon. Harvest the stalks when they've gotten thick, and use the base in the same way you would garlic, by crushing, chopping or bruising to release the oils. Use the stalks for stirfries and flavoring your meat and seafood, and use the bruised leaves for a light and fragrant tea, removing the leaves when finished. This makes an excellent architectural ornamental in the landscape and even comes back from freezes through zone 8.
CitrusI know, citrus is a fruit! But it is often used as an herb or spice to add tangy flavor to food, especially limes. Pomelos are also popular in southeast Asia, and are best served with some spices and salt. Try it! The kafir lime's leaves are an essential element to flavor meals, and lemon or lime zest makes an acceptable substitute. You can also try the leaves of rangpur lime, which is a gross between the mandarin and lime. If you live where it freezes, rangpur lime is probably your best bet since the tangerine parentage helps it to survive harsh winters.
TurmericAnother member of the big family of gingers, this one is great for curries, and is what gives them that distinct rich yellow color. They're used to color all sorts of products, edible and inedible and were even used as a substitute for saffron! To use the rhizome, dry in the sun or oven and make a powder of the dried root. In the garden these look lush and beautiful, and the leaves reach over five feet tall. Give them lots of water in the growing season, and leave them in the ground where the ground doesn't freeze. I divide them and get a bigger crop every year! Delicate inflorescences bloom in tones of green, white and pink with little yellow flowers peeking out of the bracts.
Heres the result of the aforementioned herbs and spices, put to use on chicken and rice noodles! It was dee-lish!