Hot Chili Peppers and the Scoville Scale (plus 5 recommendations for new growers)

If you like a little spice in your life, peppers can bring the heat. Often, the hot pepper selection in the grocery store is a little lacking, but as gardeners, there are so many choices on what we can grow; the options are virtually limitless. However, that doesn’t mean you should ignore the old-time favorites. A homegrown jalapeno is truly a flavor not to be missed. 

Many folks new to hot peppers assume it’s all heat, but the real action is in the flavor. Many people find the Bhut Jolokia, also known as the Ghost Pepper, to have a sweet, fruity flavor besides being insanely hot. While many hot peppers are too hot to eat raw, they add beautiful depth and richness of flavor to dishes cooked with them, and of course, homemade hot sauce!

What Makes Hot Peppers Hot?

Hot peppers have chemicals called capsaicinoids, which are responsible for the heat we feel when eating them. The active ingredient in defensive pepper spray is an oil called oleoresin capsicum. It’s derived from plants in Capsicum, the genus hot peppers belong to, which ought to be warning enough to take care when handling hot peppers from the garden. 

The amount of capsaicinoids present is the main factor in how “hot” a pepper tastes. However, every individual has their own taste or tolerance for this heat. Some folks can’t stand a jalapeno, while others eat them like candy. 

The Scoville Scale

To provide a measure of relative hotness, a pharmacist named Wilbur Scoville developed a method of categorizing hot peppers. While his test was subjective and relied on human testers, modern methods involve a lab analysis using high-performance liquid chromatography. Using a mathematical formula, the results can be translated to the traditional Scoville heat units (SHU).

A pepper with no capsaicinoids, like a California Wonder bell pepper, will score a zero on the Scoville scale. A typical jalapeno, which many people are familiar with, has about 3,000 to 8,000 SHU, while at the upper end, a few extreme peppers like the habanero can reach 300,000 SHU, and one of the former world record hottest peppers, the Carolina Reaper, can reach over two million Scoville heat units.

Popular Hot Peppers for Your Garden

Not sure which one of the tantalizing chili peppers to pick? Here are a few to try on the patio or garden bed. Except for a few niche super-hot peppers, most chili pepper fans grow them for their unique flavors, and the heat is a bonus, not the main reason. The below peppers are all easy to grow, and quite productive.

Jalapeno

This is the OG of hot peppers. It is mild enough to bring tons of flavor to dishes from soups and salsas to baked goods (jalapeno cheddar cornbread muffins are not to be missed), yet with enough heat you can tell it’s there. 

You can find jalapeno plants at the garden center in spring, but they’re easy to start from seed. They’re easy to grow and a great introduction to the world of growing your own spicy food. Jalapenos can be harvested green or left on the plant until they turn a bright, firetruck red. The red ones are typically a bit hotter, especially if you notice the white striations on the skin. 

Habanero

The habanero hails from South America and at one time was named by the Guinness Book of World Records as the world’s hottest chili. Don’t let that throw you off; habaneros have been used in cooking for centuries and bring loads of citrusy, fruity flavor and, of course, heat. 

Habaneros begin green and ripen most commonly to orange or red, although many different color varieties are available. They’re small, 1-2.5 inches long, and more shaped like a wrinkled golf ball than a long skinny pepper you may think of as a typical hot pepper. Habaneros are fantastic for adding flavor and heat to sauces and marinades, and the plants are gorgeous when hung with brightly colored mature fruits.

Serrano

Perusing the produce aisle, you could be forgiven for mistaking serrano and jalapeno peppers. Both are similar in shape, green, and about 3-4 inches long. Serranos are meaty peppers, perfect for roasting, and taste similar to jalapenos but with a bit more punch. 

Plants can get large, frequently 3-4 feet tall, and may produce fifty or more peppers each. If you’re unsure if you’ll like the flavor, serranos are easy to find in the grocery store, so you can try them before you grow.

Tabasco

The pepper that gave the famous hot sauce its name, Tabasco peppers are a staple in Cajun and Creole cooking. Small, elongated fruits cover the plants and ripen from yellow-green to orange and red. Tabasco peppers are about five or six times hotter than a typical jalapeno.

Tabasco pepper plants can reach four or five feet high, and are frequently covered in gorgeous brightly colored fruits, looking like a holiday decoration. Dry them in a dehydrator overnight and grind them into powder, or use them in a salsa roja or for a fresh batch of homemade hot sauce.

The Ghost Pepper (Bhut Jolokia)

With a name like Ghost Pepper, you likely already feel a sense of caution. Another World Record holder at one time, and still one of the hottest peppers in the world, the ghost pepper is famous for its heat. If you want it hot or just want bragging rights, give these a try. The fruits are thin-skinned and red or orange when mature, although white, purple, and chocolate-colored varieties are available. 

Hot pepper aficionados claim the heat doesn’t “kick in” for 30-45 seconds–your mileage may vary. Known for their sweet, smoky, fruity flavor, they are often used for hot sauces or dehydrated to use as chili flakes to make the heat more controllable.  

How to Grow Your Hot Peppers Even Hotter

Hot peppers are one of my favorite crops to grow, not because I use them a ton in my cooking, but because they’re just fun. Many peppers ripen to fantastic shades of reds, purples, greens, orange, yellow, and are prolific producers. A container-grown Thai hot pepper plant can have dozens or hundreds of deep, smoky red fruits contrasting with its deep green foliage. Just perusing the selection of hot peppers and seeing the pictures of the gorgeous peppers can make you start planning a garden expansion.

Hot peppers are all members of the same genus, Capsicum.  Germinating, growing, and caring for them is pretty much the same regardless of which variety you choose, although maturity dates vary widely. Early jalapenos can be ready to pick at about 60 days, while habaneros can take over three months to mature. 

Provide full sunshine and fertile, well-drained soil for the best hot pepper crop. Many peppers are slow to get started, so in all but the longest growing season, starting your hot pepper plants indoors and transplanting them outside well after the last frosts is the way to go. Hot peppers are notoriously poor at germination, so start twice as many seeds as you want plants. Many varieties will only germinate at about 60%. 

Gardeners can alter the growing environment to turn up the heat a bit on their favorite varieties. Like the soil and weather can affect the flavor of wine grapes, so can the growing conditions affect the amount of heat in a pepper. 

Stress your pepper plants: Once the pods have formed, hold back a little on the water, allowing the plant to start suffering (similar again to wine grapes). Wait to provide water until a few leaves are starting to look slightly less perky, but don’t overdo it. Actual drought stress won’t help your crop.

Harvest when mature, but don’t wait too long: Waiting for those peppers to finally turn color can be agonizing–it seems to take forever. But the wait is worth it. Capsaicin keeps accumulating for a while. Don’t let the pepper hang too long, however, as those compounds will eventually start to decline. For many varieties, the peak heat begins about a month after the fruit has set.

Provide some nitrogen: While peak capsaicin levels appear to happen at both a nitrogen stress level and with some excess, starving the plant will yield few peppers. Apply a modest amount of high-nitrogen fertilizer regularly, whether an organic or synthetic product. A healthy, vigorous plant will yield premium peppers.