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Serrano Pepper Plant Care: How to Grow and Harvest Serranos

Written by MasterClass

Last updated: Nov 10, 2021 • 5 min read

Serrano peppers add a kick to pickling mixtures and salsas, and they’re easy to grow in a vegetable garden.

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What Are Serrano Peppers?

Serrano peppers (Capsicum annuum) are long and thin, resembling a smaller version of jalapeño peppers. Serrano chiles are yellow, orange, red, or green peppers, changing color as they ripen. Serrano pepper plants can grow to be five feet tall and produce up to fifty peppers. Serranos are mostly grown in Mexico and originated in the mountainous regions of Puebla and Hidalgo. Like jalapeños, they have a bright, fresh kick with a medium to medium-hot spice level that varies depending on their size.

Serrano peppers rank between 10,000 and 23,000 Scoville heat units, making them hotter than anaheim or paprika peppers, but not as spicy as habañero or ghost peppers. While serranos can serve as a flavorful garnish for a variety of dishes, they are primarily sliced up and mixed into salsa, pico de gallo, and guacamole.

3 Types of Serrano Peppers

Serrano peppers come in various sizes and colors, with those qualities dictating the heat and flavor of the individual peppers. Some of the types include:

  1. 1. Hidalgo peppers: The hidalgo variety grows two-and-a-half inches long and only half an inch wide, making it a more narrow serrano pepper. Bright and fiery red when ripened, this traditionally Mexican pepper has a medium-thick flesh and is excellent in salsas.
  2. 2. Serrano purple: These uniquely colored peppers ripen from green to purple, eventually turning red. Stouter than other peppers, the serrano purple can grow to be three inches long and an inch wide.
  3. 3. Hot rod peppers: These longer peppers start as a dark green and can grow to be four inches long and just half an inch wide. They have a green stem and leaves.

How to Plant Serrano Peppers

Serrano peppers are a good source of capsaicin, which is responsible for the heat the peppers produce and is a cholesterol-lowering nutrient. As such, the spreading of pepper seeds in your garden can lead to healthy recipes and ingredients that spice up homemade hot sauce. Follow these steps to add serrano plants to your garden:

  1. 1. Secure growing conditions. Serrano pepper seeds need rich, loamy soil, full sun, and ample space to grow. With lots of watering involved, soil moisture will get high, so you’ll also want pots or beds that drain well.
  2. 2. Enrich the soil. Before planting your serrano seeds, you'll first want to up the soil's nutrients as they will help your plant flourish. You can do this by growing in mostly organic matter (a homemade or purchased compost) or by conditioning your soil with fertilizer, precisely one containing twice as much phosphate and potassium as its nitrogen content.
  3. 3. Plant after the last frost. Plant your seeds on an overcast but dry day, after the last frost has passed. The growing season for serrano peppers is in warmer weather.
  4. 4. Choose a sunny spot. Sow your serrano seeds in an area that gets direct sun. Serrano plants grow best with at least six hours of full sunlight per day.
  5. 5. Space out accordingly. A single serrano plant can hold fifty pepper pods, so you’ll want to space out your seeds by about a foot and a half. After planting the seeds, water thoroughly.

How to Care for Serrano Pepper Plants

Growing and caring for these hot peppers is relatively straightforward, with proper watering and fertilizing ensuring their success and richest flavors. For the best results, grow these chili peppers in warmer climates that enjoy warmer springs and summers, and follow these tips:

  1. 1. Water serrano pepper plants thoroughly. Serranos require a lot of water, and that means you'll want to water them thoroughly every three to four days, more often on hotter days during the growing season (late spring and summer). Poke your finger into the soil to see if it's wet; if the top layer is dry but an inch under is moist, you can go another day without watering.
  2. 2. Ensure your plants get plenty of sun. Sunlight is critical whether you are seeding a single serrano plant in a pot or growing more varieties in a garden. If growing in a pot indoors, be sure to have it on a windowsill or somewhere that will receive direct sunlight.
  3. 3. Fertilize monthly. Serranos will consume a fair amount of nutrients, so fertilize the plants with fresh organic matter once a month to keep them healthy and strong.
  4. 4. Add in some mulch. A fresh layer of mulch added atop your soil during hotter months can help the soil retain water and stay cool. Only do this after the surface has heated; soil temperatures should be warm to the touch come early summer, which is a good time to introduce a protective layer of mulch.

How to Harvest Serrano Peppers

Growing serrano peppers allows you to harvest and prepare them in several different dishes. They will have the same snap, crunch, and vibrancy of bell peppers but with an added layer of heat. Learn how and when to harvest them to maximize freshness:

  1. 1. Check the height of your plant. Somewhere around the three-month point, your serrano plant will have matured and reached two to three feet in height. This means the plant’s fruits are ready or near ready to be picked.
  2. 2. Pepper length will indicate readiness. It's not only the height of your plant that will indicate ripeness—the length of the pepper will similarly telegraph it is ready for picking. Once the pepper exceeds two-and-a-half inches, it is likely ready to be picked. If it is three to four inches, all the better—the more pepper there is, the more there is to chop and cook.
  3. 3. Pick based on color. The color indicates ripeness, and serrano peppers ripen from green to orange to red. With shears, snip your pepper from the stem when it is a dark green, and the pepper is just starting to turn reddish. For added spiciness, wait until the pepper reddens further.
  4. 4. Rinse and store. After picking your three-inch, reddish peppers, rinse lightly with cold water and then let them fully air dry on a paper towel. Place the dried peppers in a paper bag, and store them in the fridge for up to a week.

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