Pak choi is really easy to grow. It can do well in a polytunnel and can help fill in gaps with a quick-maturing crop in either the spring or the late-summer/ autumn. This is a Chinese brassica, or Chinese cabbage, as it is sometimes known and can be a useful crop for the home grower. This tasty leaf vegetable can be picked as cut-and-come-again baby leaves for salads or stir fries or as a mature crop for a range of different Oriental recipes.
Pak choi will grow well in any moisture retentive soil. It must be kept relatively cool and moist or the leaves will lack flavour and plants may bolt and will be more prone to disease. Mulch, provide shade and water well, especially during warmer periods. Bolt resistant varieties are available but most pak choi are best sown before or after the hottest part of the year, either just after the last frost date in your area or later in August for a late-season crop. Bolt resistant varieties can be sown any time between April and August.
Pak choi can be sown indoors earlier and planted in the polytunnel or elsewhere in the garden as seedlings. Of course if you decide to do this then you must be sure to harden off the pak choi seedlings before you move them to their final positions. Alternatively, you may simply sow seeds where they are to grow. Thin to a spacing of 7-10cm as they grow – this spacing is sufficient for plants that will be harvested for baby leaf. For semi-mature plants, increase this spacing to around 20cm by eating every second plant.
Like any leafy vegetable, pak choi will appreciate a nitrogen rich soil. They will benefit from high nitrogen organic mulches and liquid feeds (a home-made nettle or grass clippings 'tea' will work well). Pak choi may also benefit from nitrogen fixing companion plants. Peas and beans may work well and can also provide shade from hot sun. If flea beetle becomes a problem you can plant radishes as a trap crop to draw them away from your pak choi. Alliums such as garlic or onions may also been good companion plants for repelling pests. To prevent other problems, the key thing with pak choi is to make sure that it is always well-watered throughout the growing season.
Pak choi can be harvested for cut-and-come-again leaves in as few as 30 days from sowing the seed and can be harvested semi-mature or full sized in a couple of months. It is possible to harvest smaller amounts from pak choi plants over a fairly long period. Simply take leaves as and when they are needed.