Bok Choy photo by Stephanie Suesan Smith
Bok Choy photo by Stephanie Suesan Smith

Bok choy, also known as pak choi (Brassica rapa var. chinensis), originated in Asia but is grown in the United States by a lot of people. It has a mild flavor and is not as picky about conditions as Chinese cabbage. I use it in stir-fries.

Description  

Bok choy has green leaves and a white base, and white petioles. It grows to be one to two feet tall and spreads one to one and a half feet.

How to Care for Bok Choy

Here are the things you need to know to grow bok choy.

Light 

Bok choy needs full sun to partial shade. In hot climates, partial shade will help keep the plant from bolting as early in the summer. In cooler climates, planting in the full sun works better.

Soil 

The soil needs to be well-drained and have lots of organic matter in it. I till the ground to a depth of six inches, then spread three inches of compost (not manure, it spreads diseases) on the area I tilled up. I then mix the compost into the tilled soil. Bok choy needs a pH of 6.0-7.5.

Planting 

In the spring, it is best to start seeds indoors four to six weeks before the last frost date. Plant transplants six to twelve inches apart, depending on the mature size, after all danger of frost is over.

In the fall, you can plant seeds 1/4 to 1/2 inches deep and about an inch apart. When the plants come up, thin to one every six to twelve inches, depending on mature size. You can also start seeds indoors and transplant the seedlings.

Water 

Keep the bok choy evenly moist. I bought an inexpensive water meter, which helps me track when my plants need water. In cooler climates, an inch of water a week is adequate. In hotter climates, more water may be needed to keep the soil moist.

Temperature 

Seed germinates when the soil is 50-80 degrees F. If the plants are exposed to frost or a week of weather colder than 50 degrees, they will bolt prematurely. Wait until after the last frost to direct seed or transplant the seedlings. In the fall, plant seeds four to six weeks before the first frost.

Fertilizer 

After preparing your soil by tilling and mixing in compost, it is best to get a soil test to tell you what nutrients your soil needs to grow bok choy. In the absence of a soil test, spread 10-20-10 into the soil before planting and mix it in the top two to three inches of soil. Every four weeks until harvest, reapply 10-20-10 along the row and about six inches from the plants. Water after fertilizing.

Harvest

Harvest baby bok choy when it has grown as large as you want it. Harvest other bok choy when it has ten to fifteen leaves. If bok choy gets more than fifteen leaves, it can become bitter. You can harvest the outer leaves and leave the plant growing for repeated harvests until it gets too hot or frosts.

Diseases of Bok Choy

Leaf spot and downy mildew tend to occur when it is rainy, and the temperatures are high. If such weather is coming up and the bok choy is large enough to harvest, it would be wise to harvest before the rains start. Otherwise, you can get a fungicide allowed on vegetables and spray it on the bok choy. Most organic fungicides have copper in them and will work on these diseases.

Pests of  Bok Choy

Aphids and various cabbage caterpillars are the main pests of bok choy. Aphids can be dealt with by spraying the bok choi with an insecticidal soap that is allowed on vegetables. Cabbage caterpillars can be treated with spinosad or BT. Neither hurts humans.

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