Yu Choy Sum
Brassica Chinensis Var. Parachinensis
Yu Choy Sum, also known as Brassica Chinensis Var. Parachinensis, is a fast-growing leafy green vegetable prized for its tender leaves and mild flavor. Originating from Asia, it is a staple in many cuisines and is easy to grow, making it a favorite among home gardeners.
Everything it needs
9 essentials at a glance
Watering
Yu Choy Sum prefers consistently moist soil, requiring watering every 2-3 days during warm weather.
In cooler months, reduce watering to once a week. Ensure the soil is well-drained to prevent root rot. Signs of over-watering include yellowing leaves and a mushy stem, while under-watering may cause wilting and dry leaf edges.
Light
This plant thrives in full sun, requiring at least 6-8 hours of direct sunlight daily.
It can tolerate partial shade but may result in slower growth and reduced yield. Ideal placement includes a south-facing garden bed or a sunny windowsill.
Soil
Yu Choy Sum prefers loamy, well-draining soil with a pH range of 6.0 to 7.5.
A recommended potting mix includes a combination of compost, peat moss, and perlite to enhance drainage and nutrient retention.
Humidity
This plant enjoys moderate humidity levels around 50-70%.
To increase humidity, mist the leaves or place a humidifier nearby. Signs of humidity stress include leaf curling and browning tips.
Temperature
Ideal growing temperatures range from 60-75°F (15-24°C).
Yu Choy Sum is best suited for USDA hardiness zones 3-10. It can tolerate light frost but should be protected from extreme heat above 85°F (29°C) to prevent bolting.
Fertilizing
Use a balanced fertilizer with an NPK ratio of 10-10-10 every 4-6 weeks during the growing season.
Signs of nutrient deficiency include yellowing leaves (nitrogen), purple stems (phosphorus), and poor growth (potassium).
Pruning
Pruning is not typically necessary, but you can trim off any yellowing or damaged leaves to encourage new growth.
Use clean, sharp scissors or pruning shears to avoid disease transmission.
Repotting
Repotting is usually not required unless grown in containers.
If the roots become crowded, choose a pot that is 1-2 inches larger in diameter. Signs it needs repotting include roots growing out of the drainage holes and stunted growth.
Propagation
Yu Choy Sum can be propagated from seeds.
Sow seeds ¼ inch deep in well-prepared soil in early spring or late summer. Keep the soil moist until germination, which typically occurs in 7-14 days. Thin seedlings to 6-12 inches apart once they reach a few inches in height.
When it's unhappy
Yellow leaves
Why it happens
This can be caused by nutrient deficiency, over-watering, or insufficient light.
How to fix it
Ensure proper fertilization, check soil moisture levels, and provide adequate sunlight.
Bolting
Why it happens
Bolting occurs when temperatures are too high or the plant is stressed.
How to fix it
Provide shade during extreme heat and ensure consistent watering to reduce stress.
Pest infestations (aphids, cabbage worms)
Why it happens
Pests are attracted to the tender leaves of Yu Choy Sum.
How to fix it
Inspect plants regularly and use insecticidal soap or neem oil as a preventive measure.
Root rot
Why it happens
Over-watering and poor drainage can lead to root rot.
How to fix it
Ensure pots have drainage holes and allow the soil to dry slightly between watering.
Leaf curling
Why it happens
Leaf curling can indicate low humidity or pest damage.
How to fix it
Increase humidity through misting and check for pests on the undersides of leaves.
Care through the year
Spring
In spring, sow seeds directly into the garden or containers, ensuring consistent moisture and full sun exposure for optimal germination.
Summer
During summer, monitor for pests and provide shade during extreme heat. Water regularly to prevent stress and bolting.
Fall
In fall, continue to harvest leaves regularly to encourage new growth and consider planting a late crop before frost.
Winter
In winter, protect plants from frost with row covers if grown outdoors. If indoors, ensure they receive enough light and maintain humidity.
Toxicity & Safety
Yu Choy Sum is non-toxic to pets and children. It is safe for consumption, and no parts of the plant are known to cause harm.
Good to know
How often should I water my Yu Choy Sum?
Water Yu Choy Sum every 2-3 days in warm weather, and reduce to once a week in cooler months, ensuring the soil remains consistently moist.
What light conditions does Yu Choy Sum prefer?
Yu Choy Sum thrives in full sun, requiring at least 6-8 hours of direct sunlight daily for optimal growth and yield.
How can I prevent my Yu Choy Sum from bolting?
To prevent bolting, keep the plant in a shaded area during extreme heat and ensure consistent watering to reduce stress.
What type of soil is best for Yu Choy Sum?
A loamy, well-draining soil with a pH range of 6.0 to 7.5 is ideal for Yu Choy Sum, promoting healthy growth and nutrient absorption.
When is the best time to plant Yu Choy Sum?
The best time to plant Yu Choy Sum is in early spring or late summer, allowing for optimal growth before extreme temperatures.
Can I grow Yu Choy Sum in containers?
Yes, Yu Choy Sum can be successfully grown in containers, provided they have adequate drainage and are watered regularly.
What are the signs of nutrient deficiency in Yu Choy Sum?
Signs of nutrient deficiency include yellowing leaves (nitrogen), purple stems (phosphorus), and stunted growth (potassium).
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