How to Plant, Grow, and Care for Serrano Peppers

Peppers are an excellent backyard crop to grow—each compact plant produces prolific amounts of fruit. With two or four, you’ll grow baskets full of produce. This variety sprouts spicy little green or red fruits. Each one can range from 10,000 to 23,000 Scoville units, meaning ‘Serrano’ peppers are two to four times as spicy as the hottest jalapeños!

This variety is a staple in the backyard and the kitchen, especially for spice lovers and pepper enthusiasts. ‘Serrano’ makes salsas, stews, and casseroles punchy. When smoked, they add a deliciously complex flavor to meats, vegetables, and beans. 

Plant ‘Serrano’ today and enjoy its crunchiness, tanginess, and sometimes overwhelming spiciness! Whether you’re new to hot peppers or are a lifelong chile grower, this variety makes a superb addition to the garden.

What Is It?

‘Serrano’ is a type of chile similar to jalapeños. The fruits are slightly shorter and spicier. Their short bodies are meaty with thin skin and grow on an average-sized plant two to three feet tall. They grow to a width of two feet and require some space in the garden when fully mature.

‘Serrano’ now grows worldwide during spring and summer. They appreciate direct sun, warm temperatures, and good airflow. They survive perennially in regions without winter frost and as annuals in all other areas. Like most other peppers, they do not tolerate freezing conditions.

Characteristics

‘Serrano’ pushes out thin, herbaceous stems. Their trunks become woody over time, while the rest of the plant remains green. Off the stems sprout bright green leaves and white flowers. When pollinated, the white flowers morph into two to three-inch green peppers. Throughout the summer season, green chiles ripen to a deep red color. 

Peppers gain considerable heat, sweetness, and flavor as they age. Try them at all stages of ripeness to discover your favorite. Different states of ripeness coincide with various recipes, so having all stages of ‘Serrano’ fruits allows you to cook a wide range of dishes.

This type’s scientific name is Capsicum annuum ‘Serrano.’ It is a member of one of five main species of domesticated peppers. Many other species originate in South America and Asia, and some have roots in parts of Mexico and North America. They all appreciate warmth, sunlight, regular water, and good drainage. 

Propagation

Propagating chiles is easy enough with the proper tools. Chiles also need some time indoors in most areas of North America with winter cold. This gives them a jump start on the season so they produce lots of fruit and flowers under the summer sun.

Once peppers grow from seeds, you can propagate them further with cuttings. Read on and learn about both methods.

Seeds

For best results, sow seeds eight to ten weeks before your last average frost date. Fill five-inch pots with potting soil. Then, take your seeds and place two of them a quarter inch deep in each pot. Water well, and use a seed germination heat mat to help the seedlings sprout. Pepper seeds need light and heat to germinate.

Place the pots under a well-lit windowsill or grow lights. If using grow lights, keep them on for at least 16 hours. Under a windowsill, they naturally increase in size as the days lengthen from winter to spring. However, you need a good light source. Many windowsills do not have enough light to support early pepper growth.

Ensure the soil stays moist but not soggy, and the seeds will germinate in 10-25 days. Keep them under lights and ensure they receive enough water as they mature. As they grow they may get root-bound in their pots. Root-bound peppers frequently dry out and exhibit slow growth. Transplant overgrown ‘Serrano’ plants into quart or gallon pots with fresh soil.

Cuttings

Once your chile plants have multiple stems with prominent growth, you can take cuttings and increase your pepper supply. Take six-inch cuttings in early spring or summer. Strip off their lower leaves and leave the top ones to continue growing. Stripping the leaves helps the cuttings sprout roots beneath the soil. 

With snips or scissors, cut the top leaves’ edges so they stop growing. This further encourages the plants to grow roots, as they’re now forced to put all their energy into root production. 

Take your snipped cuttings and bury them two inches deep in pots with potting soil. Water well, and place the cuttings inside under a windowsill with bright light or outside under dappled shade. Add a humidity dome for increased rooting success. Monitor your baby plants and ensure their soil stays moist but not soggy.

After a week and up to a month later your cuttings should sprout roots. Successfully rooted plants sprout new growth from their stems, while unsuccessful ones drop their leaves and show signs of rot. Throw the rotting ones into the compost, and transplant the rooted ones into the garden or a container. 

Planting

Peppers thrive in raised beds, containers, and the ground. With one in a container or five in a raised bed, this variety impresses growers with its sheer productivity. Give ‘Serrano’ moderately draining soil with lots of compost or other organic material, and they’ll create loads of fruit. 

Plants may experience slow growth and have little flowers when their soil is extremely sandy or thick with clay. With the proper soil, peppers thrive with little input and maintenance. 

Preparation

Prepare the site by mixing in compost with the existing soil. Peppers appreciate drainage and nutrition—they benefit from an active soil biome with worms, bacteria, and fungi. Adding compost to the soil inoculates it with these things and adds nutrients ‘Serrano’ loves. It also increases drainage with chunky particles and porous humus. 

Let’s say you’re planting now and don’t have time to make compost. Worry not, as there are a few alternatives to use. Mix these options into the soil or add them on top:

Other amendments like kitchen scraps, plant clippings, and rotting material are best for burying underneath the peppers. As ‘Serrano’ matures, its roots reach down into these amendments while they decompose. 

‘Serrano’ thrives in containers too. They need containers with a minimum depth of 8 inches and a width of 16 inches, although they appreciate extra space. Fill the containers with potting soil mixed with compost. 

Transplanting

With their home prepared, your peppers are ready to move in. Dig a hole twice as deep and wide as the root ball. Add soil back to the hole so transplants are at ground level. Then, fill the sides with soil and press them down. Keep adding soil until it reaches the trunk’s base and water well. 

Once the plants settle, apply a layer of mulch. Top dressing with a few inches of mulch keeps the soil moist and cool during heat waves and warm and cozy during cool weather. Ensure your mulch is placed at least a couple of inches away from the base of your plant to prevent rot. 

Space ‘Serrano’ plants a foot to two feet apart. Bushy and compact peppers fit nicely among crops like tomatoes, onions, and beets. Plant one per container, unless your container is larger than five gallons with a large width. Depending on their size, big grow bags fit more than one—aim to give each ‘Serrano’ at least five gallons of space.

At transplanting, you may choose whether or not to “top” your plants. Topping cuts off the top part of the stem to encourage dense, bushy growth. This is optional and not necessary for optimal fruit production. Choose whether you’d like a shorter, denser ‘Serrano’ by snipping its top or a taller, skinnier one by leaving it alone.  

How to Grow

Throughout the season, ‘Serrano’ chiles thrive with little maintenance. They appreciate a few things throughout their lifetime. With some extra care and love, these plants produce copious amounts of peppers. The challenge, then, is finding enough recipes to use them all!

Light

‘Serrano’ appreciates full sun with six to eight hours of direct sunlight. To form lots of fruit, peppers use their leaves to photosynthesize energy and sugar. It then uses these products to make sweet, spicy, and juicy fruits.

Without enough light, ‘Serrano’ stems stretch and become long and scraggly. Under shade, the plants produce fewer fruits and flowers than chiles grown in proper full sun. However, in areas with high heat, afternoon shade will benefit the plant and protect its foliage from scalding.

The same is true for peppers growing inside before the last frost—they need bright light for six to eight hours on a windowsill. Use grow lights for peppers if they don’t have access to a bright window. 

Water

Peppers like regular water during flower and fruit formation. The fruits are incredibly juicy, and all that juice comes from the water they drink. ‘Serrano’ exhibits slow growth and fruit drop when it has too little irrigation.

Water weekly or more during cool early springs and summers. The best way to know if they’re thirsty is to check the soil. Stick your finger down as deep as it will go into the dirt, and pull it out. You don’t need to water if it feels moist below the surface. If the soil is sandy and dry, your plants need a refreshing soaking. In hot summers, ‘Serrano’ needs water every one to three days.

A container-grown ‘Serrano’ dries out quickly and needs more water than ones grown in the ground. Under the summer sunshine, you may have to water them daily and twice a day when heat waves occur. 

Soil

Part of proper watering lies in using the correct soil. Soil health is everything when it comes to growing plants, and studies show the benefits of having an active soil microbiome. ‘Serrano’ also appreciates drainage, nutrients, and moisture.

The best way to give chiles all they need is by adding compost, manure, or a similar material into their soil. This helps them have a jump start at transplanting, and it sets them up for success as mature adults. Their roots will continue to grow deeper and further into the soil, searching for nutrients.

These amendments add much-needed nutrients like nitrogen, phosphorous, and potassium. Add a dose of organic fertilizer to the soil at planting if incorporating a low-nutrient amendment like coco coir. 

Use soil with a slightly acidic to neutral pH, from six to seven. Most potting soils are already at this pH. In existing soils that are too acidic, alkaline, or nutrient-poor, add amendments ahead of the season to alter their composition.

Temperature and Humidity

‘Serrano’ fruits grow spicier and sweeter the hotter temperatures are. Direct sunlight helps them achieve this, although in cool summer areas, peppers may require more heat than they receive. In this case, plant them along a south-facing wall where heat traps itself. This helps ‘Serrano’ fruits warm up when the weather is mild. 

This variety appreciates average humidity with airflow. Ensure the soil is kept moist in dry climates—let the soil dry out before watering in wet areas. This helps moderate the moisture levels around your plants when extremely high or low. 

Fertilizing

With organic amendments in the soil, peppers need little else in the way of nutrients. Once established, they benefit from one to two applications of an organic fertilizer. Apply either a liquid or powder before the plants set blossoms. 

Maintenance

‘Serrano’ specimens appreciate maintenance through cutting off any dead or diseased foliage and stems. Monitor for pests and diseases, and apply compost to the soil if the top layer thins. Harvest peppers as they form so the plants continue producing fruits and flowers until the first frost. 

Although not necessary, ‘Serrano’ benefits from staking or caging. Add a bamboo stake, trellis, or tomato cage, and the plants will cling to it as they grow. This makes for easy harvesting once the fruits hang down and ripen. 

As the last frost date approaches your region, hard prune the stems to help ripen the fruits faster. A hard prune takes the pepper’s energy from growing new leaves, stems, and shoots and redirects it toward fruit and seed formation. To hard prune, cut off all branches above ripening fruits and snip the flowers. Remove a third of the plant’s leaves to let sunlight penetrate the interiors. 

Harvesting

Here’s the fun part! Harvesting peppers is a fantastic reward for all the hard work you’ve put into maintaining your crops. Pick them continuously as they ripen, and eat or preserve them. Slice them with herbal snips or pruners, and cut the stems above the top of the fruit. Consistently harvesting encourages plants to produce more as they rush to create seeds. 

Peppers contain capsaicin, a chemical that makes them spicy and punchy. Wear gloves while you harvest, and avoid touching your eyes. Capsaicin leaches from the fruits, stems, and leaves and irritates sensitive skin. Take care while cooking and harvesting them. 

Because of their worldwide presence, chile peppers have a wide range of uses in the kitchen. Read on to learn how to preserve them and cook them in recipes.

Uses

Eat ‘Serrano’ fresh in salsas or pickle it to dampen the spice. Use them in a spicy cooking base, blending them with onions, cilantro, bell peppers, and garlic. Then, saute the mixture in oil before you add your food. Another way to utilize fresh chiles is in soups, stews, or grilled meals. 

I often grow too many chile plants and have to find ways to keep them for months. There are two common methods of preservation: drying and freezing. ‘Serrano’ has thick flesh and is difficult to dry, although it’s not impossible. Dry the fruits by stringing them up by their stems in an area with airflow and indirect light.

Freezing the fruits is easier than drying them. Simply place the peppers in a closed container and freeze them. Both frozen and dried peppers last for at least a year.

Common Problems

‘Serrano’ is low maintenance and typically experiences few issues. They have some pests, and some viruses infect varieties of Capsicum annuum. With a little care and attention, your inflicted plants will be healthy in no time. 

Yellow Leaves

All peppers appreciate drainage and full sun and will grow sickly when these conditions are not met. A few yellow leaves are normal, especially lower on the plant. As they mature, the older leaves crowd out the younger leaves, yellow, and fall off.

If your plant has excessive yellow leaves, it could be root rot, low light, insufficient nutrients, or improper watering. Most of the time you can simply correct the moisture levels in the soil to improve their conditions. Yellow leaves during fall and winter are a normal response to the cold and wet weather.

Blossom-End Rot

The condition called blossom-end rot is a common in tomatoes and peppers. Typically a calcium deficiency causes it, although infrequent irrigation and a low soil pH also cause it. Proper soil fertility and watering generally fix this problem. Ensure your soil is good to go ahead of the season, and maintain a watering schedule that accounts for local rains. 

Pests

‘Serrano’ experiences attacks from aphids, flea beetles, and whiteflies. They are a host for pepper weevils that attack the fruit later in the season. Remove aphids easily with a strong jet of water daily for a week. By the end of the week, there should be little or no aphids left on your plants.

Early in the growing season, add row cover to plants in areas with high infestations of flea beetles and whiteflies. Add hoops to the area, and drape plastic over the sides of the hoops. Clasp the plastic down and open the ends daily to let air flow through. 

Later in summer, protect peppers from weevils by harvesting the fruit continuously. Pick green fruits and let them ripen inside where weevil infestations are severe. 

Applying organic horticultural oil or soap is an option for severe pest infestations, although it may interfere with the pollinator and predator species in your garden. Leaving a few pests each year invites predators like ladybugs into the garden, where they feast on the bugs for you. 

Diseases

‘Serrano’ chiles have a few diseases that pester them, like root rot and powdery mildew. Avoid root rot and similar fungi with proper drainage, irrigation, and airflow. Ensure your plants have enough space and sunlight, as well as soil with good drainage.

Tobacco mosaic virus is an incurable disease that often spreads via infected soil, and insect pests. Leafhoppers are one vector species that spreads mosaic viruses. Control them to control the spread of the disease. If your pepper leaves become mottled with yellow, it’s possible you’re dealing with it. There is no cure. It’s best to destroy the plant and avoid planting susceptible species in the area.

Frequently Asked Questions