Ong Choy Seeds - Kong Xin Cai - Kangkong

10, 11

USDA Zones 10-11 - Grows as a perennial in these zones. It is extremely sensitive to cold and will not tolerate frost. In all other zones, it must be grown as a warm-season annual or as an indoor houseplant.

Best performance in Zones 9-11 where long, hot, and humid summers provide ideal growing conditions.

Northern Zones (2-9) - Start seeds indoors 6-8 weeks before the last expected frost date. Do not transplant outdoors until all danger of frost has passed and night temperatures are consistently above 55F. Can be grown in containers and brought indoors for winter.

Hot Climate Zones (9-11) - Can be direct sown or transplanted outdoors in early spring. Will thrive with a long, warm, and humid growing season.

Soil Temperature - Requires warm soil for germination, with an optimal temperature of 70-85F. Seeds can be slow to germinate without warm soil.

Growing Season - Requires 30-40 days to maturity from seed, but can be harvested sooner as a baby green. This makes it an excellent crop for succession planting.

Learn more about USDA Hardiness Zones here

When to Plant:
Start seeds indoors 6-8 weeks before your last expected frost date. Ong Choy is very sensitive to cold, so do not plant outdoors until all danger of frost has passed and night temperatures are consistently above 55F. You can also direct sow seeds outdoors after the soil has warmed to at least 70F.

Location and Soil:
Choose a location that receives full sun (at least 6-8 hours of direct sunlight per day). Ong Choy prefers rich, well-draining soil with a good amount of organic matter, but it is known for thriving in wet, even boggy conditions. It can also be grown in containers or hydroponically.

Starting Seeds:

Seed Preparation: The seeds have a hard coat. To speed up germination, soak the seeds in warm water for 12-24 hours before planting.

Fill seed starting trays or pots with a high-quality, sterile seed starting mix.

Sow seeds about 1/4 to 1/2 inch deep.

Lightly cover the seeds with soil and gently water to moisten the mix.

Place the trays in a warm, sunny location or on a heat mat.

Keep the soil consistently moist until seedlings emerge, which typically takes 5-14 days.

Transplanting Outdoors:

Harden off seedlings for 7-10 days before transplanting to acclimate them to outdoor conditions.

Space plants 6-12 inches apart in the garden bed.

Dig a hole slightly larger than the root ball, place the plant in the hole, and backfill with soil.

Water thoroughly after transplanting.

Care and Maintenance:

Watering: Ong Choy requires a lot of water. Keep the soil consistently moist, and do not let it dry out. If growing in containers, you may need to water daily, especially in hot weather.

Fertilizing: Amend the soil with compost before planting. Ong Choy is a heavy feeder, so a balanced, high-nitrogen fertilizer can be applied every few weeks to support vigorous leafy growth.

Harvesting: Begin harvesting when the plants are about 8-10 inches tall. Cut the stems about 1-2 inches above a node to encourage new growth. You can harvest the entire plant or cut the outer stems to extend the harvest.

Pests and Diseases: Watch for common pests like aphids. Ensure good air circulation to prevent fungal issues in humid conditions.