How to Plant, Grow, and Care for ‘Merlot’ Chinese Cabbage

If you love the taste of ‘‘Napa’ cabbage but are looking for something new, put ‘Merlot’ on your list of brassicas to grow. This variety produces leaves with a taste and texture similar to other types of Chinese cabbage, but they’re bright purple instead of green!

‘Merlot’ has similar care requirements as other cabbages but is pickier about water and temperature. Therefore, you should pay special attention to planting time and irrigation. Keep reading to learn the ideal planting windows, how to deal with common pests, and more.

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‘Merlot’ Chinese Cabbage Overview

A vegetable cut in half, showcasing the rich contrast between its bright purple leaves and the pale white core, set against a dark background.


Plant Type Annual vegetable Species rapa var. pekinensis	Native Area Mediterranean, Iran, Africa Watering Requirements Moderate	Pests & Diseases Flea beetles, harlequin bugs, aphids, cabbage worms, cabbage loopers, black rot, alternaria

What Is It?

A crisp vegetable with tightly packed purple and white leaves is displayed on a clean white surface, its outer layers curling slightly. — Like most brassicas, ‘Merlot’ grows best in cooler weather.

While you may think all heads of cabbage are round, Chinese cabbages produce thinner leaves and upright heads. They’re popular additions to soups and stir-fries and are a key ingredient in kimchi.

Like most brassicas, ‘Merlot’ grows best in cooler weather. Since it matures more quickly than traditional cabbage varieties, it’s a good option if you’re working with a short growing season.

Characteristics

A neatly sliced vegetable with vibrant purple leaves rests beside a wooden bowl filled with diced pieces, all on a dark, rustic surface. — They have an upright, elongated shape and feature leaves with thick, crunchy ribs and thinner foliage.

While most types of Chinese cabbage have green leaves, the ‘Merlot’ variety is vibrant purple. The plants have an upright, elongated shape and feature leaves with thick, crunchy ribs and thinner foliage. The heads grow to about a foot tall and can weigh upwards of a pound.

Planting

A detailed view of richly colored leaves with a mixture of purple and light green veins, highlighting their delicate, wrinkled texture. — Since this variety is somewhat new and rare, you may have to start from seed.

You can grow ‘Merlot’ cabbage from transplants or seeds. However, since this variety is somewhat new and rare, you may have to start from seed. I recommend starting the seeds in seed trays and planting them outdoors when they’re a few weeks old.

Growing from Seed

A hand carefully holds small, dark seeds above a patch of rich brown soil, preparing to plant them in the ground. — First, make sure you sow the seeds at the right time of year.

Since it can be difficult to find ‘Merlot’ seedlings in nurseries and garden centers, you may need to start these crops from seed. Fortunately, it’s pretty simple to grow from seed.

First, make sure you sow the seeds at the right time of year. Since the seeds take about four weeks to grow into a size good for transplanting, you should sow them about a month before you want to transplant the seedlings into your garden.

The ideal planting time varies depending on your growing zone. In most areas, you can sow seeds indoors in February-March for a spring planting and again in July-August for a fall planting. Use your last frost date, and count 2 to 4 weeks for direct sowing, or 4 to 6 weeks for indoor sowing.

Regardless of when you sow indoors, start with the right planting mix and trays. You can use a variety of trays for seed starting, but you should make sure they have bottom drainage holes. When it comes to a potting mix, choose a well-draining mix that contains nutrient-rich compost or fertilizer.

Fill each of the cells with potting mix, pack it down gently, then poke a quarter-inch deep hole in each cell. Place one or two seeds in each hole, cover, and water well. Set the trays somewhere warm and keep the potting mix moist. The seeds should germinate within five days.

Once the seedlings emerge, place them somewhere that receives 10-14 hours of direct light. You can place them in a greenhouse or use grow lights to provide supplemental lighting. If you planted more than one seed per cell, thin to one plant when the seedlings have their first set of true leaves.

When the seedlings are two to three inches tall, they’re ready to transplant. Move the seedlings outdoors for a few days to harden them off. Although this may not seem necessary, it will help limit the stress they experience during transplanting.

Transplanting

Whether you grow your seedlings or purchase plants from a garden center, you should follow the same planting methods. Since this cabbage is a cool weather crop, spring and fall planting is best. However, if you want to only grow the plant once per year, fall crops are typically more successful than spring crops.

If you’re planting in the spring, you need to transplant the seedlings so they have time to mature before hot temperatures arrive. The ideal planting time depends on your growing zone, but planting near your average last frost date is your best choice. The plants can survive a light frost, but newly planted seedlings will appreciate being protected by a layer of row cover. Avoid planting the seedlings too early since more than a week of temperatures below 50°F (10°C) can encourage them to bolt (prematurely go to flower).

The best time to plant fall crops is late summer or early fall. It’s okay if they experience temperatures near 80°F (27°C) during their first few weeks in the ground. However, temperatures in the mid-80s can also cause bolting, so you should avoid planting when the weather is still hot.

When you transplant, space the plants 12-18 inches apart. Water well and keep the soil moist in the first week after transplanting.

How to Grow

A row of healthy green plants with large, textured leaves growing in rich soil, surrounded by other lush greenery in the garden. — They are slightly more challenging to grow than their green cousins.

Growing ‘Merlot’ Chinese cabbage is similar to growing green Napa cabbage like ‘One Kilo’. However, this purple variety is likelier to bolt and experience tip burn. Therefore, they are slightly more challenging to grow than their green cousins.

Light

A garden filled with large, overlapping green leaves, each one crinkled and textured, forming a dense canopy of foliage. — Aim to provide at least ten hours of bright light.

Full light is ideal for these brassicas, but they can also tolerate a few hours of afternoon shade. Aim to provide at least ten hours of bright light.

Water

These crops require a moderate amount of water to remain healthy and grow into full heads. The amount of water you’ll need to apply varies depending on factors, including natural rainfall, temperature, and humidity.

Aim to provide at least an inch of water each week. I recommend applying about half an inch of water two or three times per week rather than one inch all at once. Watering multiple times per week will help keep the soil moisture level consistent and allow for nutrient uptake.

You can water with a hose, watering can, or drip irrigation system. Regardless of your method, it’s a good idea to check the soil moisture after you water. If the top few inches of water are still dry after you irrigate, add more water.

Soil

Napa cabbage can grow in various types of soil as long as it has good drainage. Sandy soils, clay soils, and loam can all work well. However, you will need to water more often if your soil is high in sand.

Temperature and Humidity

A large plant with tightly packed green leaves that curl inward, forming a compact and textured spherical shape in the center. — If you are expecting a day or two of hot temperatures, you can cover them with shade cloth.

‘Merlot’ is more sensitive to hot and cold than other Chinese cabbage varieties, so you should pay closer attention to the temperature.

If the plants experience temperatures above 85°F (29°C), they are more likely to bolt. If you are expecting a day or two of hot temperatures, you can cover them with shade cloth. However, it’s best to time your planting dates so the crops can avoid contending with heat.

While ‘Merlot’ plants are frost-tolerant, these cold temperatures can encourage them to bolt when the weather warms again. Therefore, you should wait until the last frost passes before planting spring seedlings outdoors. If a late frost pops up, cover the beds with row cover to protect them.

Fertilizing

A gardener wearing blue gloves carefully pouring fertilizer into dark, nutrient-rich soil, with the young plants showing early growth. — If you haven’t added any compost to your soil, you may want to add a balanced vegetable fertilizer before planting.

Like most brassicas, these crops are moderate to heavy feeders. Unless your soil is high in organic matter, you should add a nitrogen source before planting. A nutrient-rich compost will supply nitrogen as they mature, but you can also add a fertilizer like feather meal.

If you haven’t added any compost to your soil, you may want to add a balanced vegetable fertilizer before planting. This product will supply the three macronutrients: nitrogen, phosphorus, and potassium.

Maintenance

A small green plant with broad leaves growing steadily in a garden bed covered in straw mulch, surrounded by soil and greenery. — Adding mulch around the bases will limit weed growth and decrease the amount of time you need to spend pulling weeds.

Fortunately, ‘Merlot’ doesn’t require much maintenance! After the plants are in the ground, you should keep an eye out for weeds and remove them when they’re young. Adding mulch around the bases will limit weed growth and decrease the amount of time you need to spend pulling weeds.

Harvesting and Storage

purple napa cabbage on cutting board — Although you can harvest and eat the cabbages at any time, the best time to harvest is after they develop dense heads.

You can expect your cabbages to be ready to harvest about 60 days after transplanting. Although you can harvest and eat the cabbages at any time, the best time to harvest is after they develop dense heads. Cabbages that are ready to harvest will feel solid when you touch them.

Grab a knife and cut near the soil line. If the outer leaves are dirty or discolored, pull them off until you’re met with a better-looking interior.

Common Problems

A vegetable with crinkled, deep purple leaves showing a textured pattern rests on a smooth, black surface, revealing its tightly packed structure. — It deals with the same pests and diseases that impact many brassicas and also faces a few unique problems.

Unfortunately, ‘Merlot’ Chinese cabbage is susceptible to various problems. It deals with the same pests and diseases that impact many brassicas and also faces a few unique problems brought on by inadequate growing environments.

Pests

A close-up of a green leaf showing a group of small, orange-black insects called harlequin bugs gathered around tiny, pearly eggs on its surface. — Adult harlequin bugs and their nymphs eat the leaves, leading to raggedy holes.

‘Merlot’ cabbages are susceptible to attack from numerous pests. Here are some of the most common ones to look out for. If you’re using organic pesticides, ensure you wash your produce well before consuming it.

Flea beetles: The small, dark beetles appear in large numbers and chew small holes in cabbage leaves. Covering with insect netting or row cover at transplanting time can keep the pests off the plants. You can also spray the pests with neem oil, spinosad, or pyrethrins.
Harlequin bugs: Although these shield-shaped bugs may look pretty, they can become serious Napa cabbage pests! The adults and nymphs eat the leaves, leading to raggedy holes. Control the pests by removing them by hand and placing them into a bucket of soapy water. Alternatively, you can spray them with neem oil or pyrethrins.
Cabbage loopers: These green caterpillars eat many brassicas, including ‘Merlot’ Chinese cabbage. Control them by handpicking or spraying the leaves with Bt.
Cabbage worms: Cabbage worms consist of a few species of moth larvae that attack crops like Napa cabbage. When left untreated, they can quickly devour the foliage. The best treatments include spraying with Bt or removing the worms and eggs by hand.
Slugs and snails: Both of these mollusks attack Napa cabbage, but they’re particularly dangerous to young seedlings. Since the pests come out at night, they can be difficult to detect and kill. Beer traps and organic slug bait are two effective control measures.
Aphids: Although aphids are small, they can quickly multiply and damage ‘Merlot’ plants. Natural predators like ladybugs and green lacewings can keep aphid populations in check, so avoid applying broad-spectrum insecticides and plant diverse flowering crops to keep these good bugs around. If aphids get out of hand, spray them with a strong stream of water. Follow up with neem oil or insecticidal soap if necessary.

Diseases

A large green leaf marred by brown spots and holes, evidence of insect or environmental damage, against a natural backdrop. — Small, brown dots on yellow leaves often indicate the fungal disease alternaria.

‘Merlot’ Chinese cabbages are susceptible to some of the same diseases as other brassicas. Keep an eye out for the following, and do your best to prevent the diseases from entering your garden.

Black Rot: This bacterial disease is difficult to control, so prevention is the best strategy. Only purchase clean seed, and avoid growing brassicas in the same spot multiple times in a row. If you spot telltale yellow and brown leaves, remove them from the garden.
Alternaria: Small, brown dots on yellow leaves often indicate the fungal disease alternaria. You can prevent alternaria by avoiding overhead watering and utilizing wide plant spacing for good airflow.

Environmental Problems

A green leaf with ragged edges and dry, brown spots, lying flat on a white surface, showing signs of wear and tear. — Knowing the factors that cause these issues can help prevent them.

‘Merlot’ is more susceptible to bolting and tip burn than other types of Napa cabbage. However, knowing the factors that cause these issues can help prevent them.

Tip Burn

A plant with thick green leaves that curl inward, revealing a slight purple tint near the edges, growing in rich soil and showing robust health. — Inconsistent or insufficient irrigation can lead to calcium-deficiency and tip burn.

A lack of calcium is often the cause of tip burn. While many people assume calcium-deficient plants mean calcium-deficient soil, this isn’t always the case! Calcium uptake is highly dependent on water, so inconsistent or insufficient irrigation can lead to calcium-deficient plants that develop tip burn.

Aim to keep the soil moderately moist as your crops grow. While you don’t have to water every day, avoid shifting between bone-dry and soaking wet soil. Setting up a drip irrigation system on a timer is one way to keep soil moisture consistent.

Bolting

bolted yellow brassica flowers — This flowering process coincides with bitter leaves, so it’s best to avoid bolted greens.

When greens like cabbage and lettuce begin to send up a tall flower stalk, gardeners say the plants are bolting. This flowering process coincides with bitter leaves, so it’s best to avoid bolted greens. It is a natural cycle that plants go through, where energy is transferred to seed production rather than leaf production.

‘Merlot’ crops are extremely sensitive to temperature changes, and a combination of high and low temperatures can encourage the plants to flower. Ideally, the temperature should remain between 50-70°F (10-21°C) throughout the plants’ lives. However, younger plants can tolerate warmer temperatures, and older plants can tolerate colder temperatures.

Frequently Asked Questions

Napa cabbage may begin to flower if the temperatures are too low or too high. Aim to avoid temperatures above 80°F (27°C) and below 40°F (4°C).

If your cabbage is a loose cluster of leaves a month after planting, the soil may contain too much nitrogen. You can avoid this problem by using a balanced vegetable fertilizer rather than a product that contains only nitrogen.

These plants don’t like hot temperatures, so you should avoid growing them in the summer in most areas. However, you can transplant your fall crop in the late summer.