Garden cress (Lepidium sativum) is a cool season annual, also known as pepper grass because of the leaves peppery flavor. It grows well in containers, and is excellent on a sunny windowsill in the kitchen for easy access. The baby leaves can be harvested as soon as the true leaves appear as Garden cress is frequently grown for sprouts.
Growing the Herb Garden cress
Cress grows well in loose soil and a sunny location. Start outdoors between one and two weeks before the average last frost. Sow seeds ½-inch deep, spaced 1 inch apart. Rows should be 6 inches apart. You can also place a line of seeds along prepared rows and cover lightly. Keep consistently moist. Seedlings should emerge in 5 to 15 days. Thin seedlings when ½ inch tall, to 2 inches apart.
For a continuous crop, repeat the planting every 10 to 14 days starting in spring. Cress can be started indoors 2 – 4 weeks before average last frost and then transplanted in garden after danger of frost. It can also be planted in containers for inside or outside. Fill container with well-draining soil. Scatter seeds across top of container and cover with ½-inch layer of soil. Keep moist.
Garden cress is suitable for growing outdoors, indoors, in containers, and hydroponics.
Garden cress grows to a height of 12 to 20 inches (30 – 50cm).
Plant Garden cress seeds 1 inch (2.5cm) apart. Thin to one plant every 2 inches (5cm) when seedlings are 1/2-inch (1.25cm) tall. Rows should be spaced 6 inches (15cm) apart.
Preferred pH Range
Garden cress prefers a relatively narrow pH range between 6.0 (mildly acidic) and 7.0 (neutral).
Cress is propagated from seeds in spring and fall. Seeds can be started inside or outside, directly in the garden or in containers.
Seed Germination Period
Garden cress seeds will germinate in soil in approximately 5 to 15 days, but can germinate in as few as 24 hours to 4 days in dedicated propagation media such as Oasis Rootcubes, Rapid Rooters, or Grodan Stonewool.
Number of Seeds per Gram
There are approximately 350 garden cress seeds per gram.
The soil should be loose, well-draining and amended with compost and a well-balanced fertilizer. Keep consistently moist.
Alternative Growing Media
Soilless potting mixes (Pro-Mix, Sunshine Mix, etc.), perlite, vermiculite, rockwool, coco peat, Oasis Rootcubes.
Sun & Lighting Requirements
Garden cress grown outdoors prefers full sun but tolerates some shade.
Cress will grow indoors satisfactorily under standard fluorescent lamps, and exceptionally well under high output T5 fluorescent plant lights, compact fluorescent, or high intensity discharge (metal halide or high pressure sodium) plant growing lights. Keep standard fluorescent lamps between 2 and 4 inches from the tops of the plants, high output and compact fluorescents approximately one foot above the plants, and HID lights between 2 and 4 feet above the plants, depending on wattage.
Have an oscillating fan gently stir seedlings for at least 2 hours per day to stimulate shorter, sturdier, and more natural plant habit.
Annual. Not applicable.
Above average water needs. Cress prefers a consistently moist soil. Thrives in hydroponics.
Potential Plant Pests and Diseases
Garden cress has no serious pest or disease issues.
Fast growing, can sprout in as little as 24 hours. Use entire baby plants for micro greens, or repeatedly cut back when thickly sown. Garden cress is an entirely different variety than Watercress and should not be confused.