When to Plant Watercress? A Detailed Guide to Key Growing Techniques

Watercress, properly known as watercress (Nasturtium officinale), belongs to the cruciferous family of vegetables and is one of the main leafy vegetables planted in autumn and harvested in winter and spring in Guangdong Province. Watercress is sweet and cool in nature, clears heat and moistens the lungs, contains various vitamins and relatively high superoxide dismutase, and has anti-aging effects. Many watercress products on the market use large amounts of nutrients to speed up growth, so it is really not easy to eat safe and healthy watercress. When is watercress generally planted? What are the key growing techniques?

1. When is watercress generally planted?

Watercress is generally planted from August to September. With advances in technology, it can now be cultivated all year round, but in northern winters it should be kept indoors.

Watercress is suitable for open-field cultivation. It is a landscaping plant for pool sides and stream banks, and can also be grown in pots for ornamental purposes. It is mainly used for greening or covering the edges of garden water features and shallow-water areas.

2. Key growing techniques for watercress

Watercress has a very short growth cycle, taking about 20-30 days from transplanting to harvest. It grows well at 15-25°C, and grows rapidly with good quality at around 20°C; below 10°C it grows slowly and can tolerate short periods of frost; above 30°C it struggles to grow and is prone to disease. The base fertilizer must be sufficient; generally no additional fertilizer is applied, but if there is no base fertilizer, one topdressing can be applied after transplanting. As the plants grow, deepen the water layer, maintaining a water depth of 5-7cm at the peak growth stage. If the water layer is too deep, the plants tend to grow leggy with many adventitious roots and yellowing stems and leaves; if the water layer is too shallow, the new stems easily become woody, affecting yield and quality. Watercress likes light; insufficient light or overly dense planting makes the stems and leaves grow weak and spindly. When harvesting, leave 1-4 of the cultivated area as seed stock for propagation.

1. Watercress seedling raising

Watercress bought from the market can be used directly for cuttings. Old stems are best, and if they have adventitious roots, they will root even more easily. Cut the watercress stems into small sections of about 10-15 cm, each with about 3-5 nodes.

Insert the cuttings diagonally into the soil to a depth of about 3-5 cm, preferably in a semi-lying position so the stems are as close to the soil surface as possible. Water thoroughly, and it is best to maintain a water level of about 1 cm.

If dividing plants for transplanting, do so about 1 month after cuttings, with a spacing of about 10 cm.

2. Daily care of watercress

It likes moisture and dislikes drought, so it needs frequent watering to keep the soil moist. Water cultivation is best, with a shallow water level; during the vigorous growth period, a water level of 3-5 cm is generally sufficient.

It is relatively cold-tolerant but not heat-tolerant. The optimal growing temperature is 15-25°C; above 30°C growth is hindered, below 10°C growth stops, and it can overwinter outdoors at around 0°C. It likes ample light, preferably 7-8 hours of sunlight per day, but during the high summer heat it is best moved to a shaded spot.

It needs a lot of fertilizer, but it is best to apply complete-element fertilizer, and spray decomposed organic fertilizer once after each harvest.

There are relatively few pests and diseases, and timely hand removal is the main method. If pest damage is severe, you can also add water to submerge the plants, drown the pests, and then drain the water.

3. Harvesting watercress

When the plants reach about 20 cm in height, the tender stems (about 10-15 cm) can be harvested.