Asian Greens

Asian greens require well-drained soil and full to part sun, 5‐6 hours of which should be direct sun.

Start seeds for Pac choi and Chinese/Savoy cabbages indoors February through March, 6‐8 weeks before desired transplanting date. Harden off seedlings to outdoor temperatures by setting them in a cold frame for one week before planting. If you do not have a cold frame, set seedlings outdoors in the day and indoors at night for a week before planting.

Transplants can go into the garden as early as two weeks before the last frost date (April 15th in Portland). Prepare the planting area by mixing 2‐3” of composted manure and lime into the top 4‐6” of the soil. In addition, mix in an all‐purpose granular fertilizer and lime in the bottom of each planting row. Asian greens are also excellent in containers at least 8” deep.

Plant cabbage seedlings 12‐18” apart in rows 18‐36” apart, and water in with liquid seaweed or B1. Cover your new planting with floating row cover to prevent attacks from cabbage loopers, aphids, and other chewing insects that love Asian greens.

Asian greens can be directly sown in your Portland area garden from March through early June. Be sure to amend the planting area with 2‐3” of composted manure before sowing seeds. Plant seeds 1⁄4” deep in rows 18‐ 36” apart. Seedlings should be thinned 12‐18” apart when they have at least two true leaves.

Seeds for a fall harvest should be started in flats throughout July and August. Seedlings can go in the ground once they have 2‐3 sets of true leaves. Fall harvested greens can be directly seeded August through September. Asian greens are very sensitive to heat, so plant them in the shade of larger summer crops such as cucumbers or potatoes.

Transplants for leafy Asian greens can go in the ground through mid September.

How much water your plants will require depends on the soil and weather. Water new transplants daily, or when the top 2” of the soil is dry. Once they reach 12 inches, Asian greens need average and evenly moist soil. Avoid overhead irrigation. Instead, use drip or flood irrigation. Hand watering is also an option. Mulch around plants to retain soil moisture.

The cabbages are heavy feeders and benefit from a side dressing of composted manure or all purpose granular fertilizer in two weeks after transplanting. Repeat side dressing once a month for the next two months. The leafier greens, Pac choi and mustard, benefit from a foliar spray of liquid fish emulsion every 3‐4 weeks.

Chinese cabbages are ready to harvest when the head is firm. Start checking when the heads reach about 12”. Leafy greens, such as mustards and Pac choi, are ready to harvest about one month after transplanting. You can pick outer leaves to maintain a continual harvest, or cut an entire clump about 1” above the ground. Wait another month for a second harvest of smaller clumps.

Heads of Chinese cabbage can be stored refrigerated for 7‐14 days after harvest. Leafy greens are best eaten fresh, but will store 2‐5 days refrigerated.

Weather and cultural conditions can affect Asian greens. Plants will bolt (go to flower) quickly in hot weather and drought. Correct planting time, moderate and consistent moisture, soil amending, and row covers are all strategies to improve growing conditions.

Damping‐off occurs in cool, wet weather. It prevents seedlings from emerging or causes seedlings to die off. Replant new seeds in an area with better drainage, or add more compost and wait for warmer weather.

Cutworms can often mow down all of your seedlings in a single night. They can also eat holes into the leaves and stems. Spinosad is an organic control for cutworms. Nematodes can also help control cutworms.

Cabbage loopers and imported cabbage worms leave large, irregular holes in leaves—coupled with bits of green excrement. They can also burrow holes in cabbage heads. For prevention, cover new seed beds with floating row cover. Spray with Bt to stop infestation.

Aphid damage often appears as curled, deformed, or yellow leaves. You may find colonies of green or grey aphids on the undersides of the leaves and growing tips. Also, sticky sap on leaves and stems and white aphid skeletons are quite prevalent. There are numerous sprays and control measures to help combat aphids.

Flea beetles chew dozens of tiny holes in the leaves. For prevention, cover new seed beds with floating row cover until plants are 8” tall. Dust with diatomaceous earth or spray with pyrethrin.

Mildews appear as white patches, preceded by reddish patches, on the leaves and stems. Both downy and powdery mildew are fungal issues. Downy mildew can also cause roots to be misshapen with rough, cracked skin. First, remove as much of the infected areas as possible. There are numerous fungicides listed for edibles, such as Serenade, that can prevent the spread of powdery mildew.

Snails and slugs leave large holes in leaves—or eat new transplants entirely—when they feed at night. They often leave iridescent trails on leaves and the ground. Slug baits and beer traps are just two ways to control them.

Club root is a soil fungus that stunts and deforms roots. It may kill seedlings or weaken older plants. Infected plants become stunted and wilt on warm days, and leaves may turn slightly yellow. There is no cure for club root, and the fungus will persist in the soil for many years. Remove and destroy infected plants, including the soil ball around the roots. Plant new transplants in a different area of the garden. Do not plant brassica crops in an area that has had club root for at least 7 years.

Fusarium Wilt will cause eaves to turn yellow, and they may twist and eventually drop off. There is no cure, and the fungus will remain in the soil for many years. Remove and destroy infected plants. Start new plants in a different area.