Pak choi, or bok choi as it is also known, 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.
Follow the table below to know when to plant pak choi, how and when to sow, how to grow, and harvesting pak choi in the UK.
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Belonging to the Brassica rapa species within the cabbage family, its cultivation traces back to China around the 5th Century. Its robust nature and straightforward cultivation process have led to its widespread adoption in various cool temperate areas worldwide, including here in the UK.
Pak choi stands out as a highly advantageous vegetable, particularly suitable for novice gardeners due to its simplicity in cultivation, swift maturation, and delightful taste.
Pak choi thrives when planted in full sun during the spring and autumn seasons. However, during the peak of summer, it benefits from partial shade to deter premature bolting.
Pak choi will grow well in any reasonably fertile, humus-rich, 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 July or August for a late-season crop. Bolt resistant varieties can be sown any time between April and August.
To grow pak choi you will need:
Pak choi seeds.
Seed trays/ pots or soil blocks if not direct sowing.
A suitable growing area.
A container and potting mix if growing in a container.
Facility to water your crop.
Organic matter for mulch/ feeds.
Basic gardening tools for planting/ weeding/ spacing, etc...
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.
Pak choi can be planted outdoors anytime between April and August, while indoor cultivation allows for year-round sowing. To ensure a continuous harvest, opt for successional sowing by planting small quantities of seeds at intervals.
If you decide to start seeds indoors for later transplanting, use high-quality, peat-free seed-starting compost in seed trays, small pots, or soil blocks.
After sowing pak choi seeds indoors, it's advisable to acclimate them gradually to outdoor conditions, a process known as hardening off. This should be done after the last frost date in your area, when the soil has started to warm up. Ideally, the pak choi seedlings should be around 10cm tall at the time of planting.
Upon planting, ensure thorough watering to help the plants establish themselves. And add an organic mulch.
For outdoor gardens, sow seeds directly after the soil warms and frost is no longer a concern. Outdoors, prepare beds well before sowing.
Plant seeds approximately 2cm deep, aiming for eventual spacings of 5-10cm for baby leaves, 20cm for semi-mature plants, and perhaps even 25-30cm for fully matured, full-sized plants.
Due to its shallow root system, Pak Choi is well-suited for container cultivation. When selecting a container for planting Pak Choi, opt for one that is at least 20-25cm wide. Ensure the container has ample drainage holes to prevent waterlogging of the soil, which can adversely affect the growth of the plants.
Fill your container with a suitable moist yet free-draining growing medium. A peat-free commercial potting mix, or a homemade mix, should work just fine as long as it contains a reasonably high proportion of organic matter.
Remember, you can grow pak choi in a wide range of locations, in the ground, in raised beds, or in containers. Before sowing or planting, you should have prepared the area to make sure that the basic growing needs of the crop can be met.
Consider sunlight, wind and water, choosing a sunny, sheltered and moist yet free-draining situation. Remove any weeds thoroughly and enrich the site with plenty of organic matter. Think about adding any physical barriers that may be required to protect the crop once it is sown or planted.
Physical barriers such as row covers, mini polytunnels or netting can be necessary when growing members of the cabbage family and pak choi is no exception. Covering your crop can help to protect it from slugs and snails, birds, caterpillars and a range of other pests.
After being hardened off, indoors sown pak choi can be planted out after risk of frost has passed. This will of course be a little earlier if you are planting in a polytunnel than it will be if you are planting outside.
Thin or plant out indoors sown seedlings to give 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 or so by eating every second plant.
This is not a crop that is challenging to care for. Mostly, caring for pak choi means watering, applying a mulch and perhaps feeding when growing in containers. Some pest protection, as mentioned above, may also be required.
Ensure your crop receives consistent moisture through watering or irrigation to prevent wilting or premature bolting, especially in hot and dry conditions. If feasible, water early in the morning rather than in the evening.
Early watering aids plant vitality and mitigates potential problems associated with late watering, such as attracting slugs, snails, and other pests.
Apply a high-quality organic mulch, such as homemade compost, around the plants. This mulch serves multiple purposes: retaining moisture in the soil, protecting against soil erosion, providing slow-release nutrients, and to some extent, suppressing weed growth.
When cultivating pak choi in raised beds or in-ground beds, maintaining adequate mulching and ensuring soil health should generally suffice to maintain a thriving crop. However, if growing pak choi in smaller containers, it might be advantageous to feed the plants every couple of weeks during the summer with a nitrogen-rich organic plant feed like nettle or compost tea.
Furthermore, companion planting with nitrogen-fixing legumes such as peas or beans can contribute to providing essential nutrients for pak choi and other cabbage family plants. This symbiotic relationship aids in enhancing soil fertility and supporting the growth of healthy crops.
Make sure that you keep on top of weeds in your vegetable garden so that your pak choi can obtain the nutrients and water it needs without having to deal with too much competition.
To prevent bolting, especially during hot and dry weather, opt for bolt-resistant varieties of pak choi in the summer months. Ensure plants are consistently watered and provide shade from the intense midday sun.
If flowering stems begin to emerge, promptly remove them and incorporate them into salads or stir-fries before the buds open. It's advisable to harvest the entire plant immediately as it will deteriorate somewhat once bolting begins. Additionally, be vigilant with other plants sown simultaneously, as they are likely to follow suit in flowering, necessitating prompt harvesting.
Do not discard pak choi that has flowered however, or which is about to do so. Unlike lettuce and some other plants, bolting won't make the leaves taste bitter. You can still harvest and eat your pak choi, flowers and all – as long as you are quick to do so.
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 to use in a range of recipes.
As a member of the cabbage family, pak choi can experience all the same pest and disease problems as its relatives. Birds like pigeons, slugs and snails, cabbage caterpillars and cabbage root fly can all become issues, for example.
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. But covering your crop is a good idea to protect from birds where these are a problem, and physical barriers may also be needed to prevent issues with common brassica pests.
To prevent problems rooted in environmental conditions, the key thing with pak choi is to make sure that it is always well-watered throughout the growing season.
Selecting the right pak choi to grow can be important. There are many different cultivars to choose from. Some highly regarded options for the UK are:
Brassica rapa subsp. chinensis ‘Baraku’
Brassica rapa subsp. chinensis ‘Choko F1’
Brassica rapa subsp. chinensis Glacier’
Brassica rapa subsp. chinensis ‘Ivory’
Brassica rapa subsp. chinensis‘Red Choi’
Brassica rapa subsp. chinensis‘Summer Breeze’
Consider carefully how you maintain fertility in your polytunnel growing areas and what you might grow alongside polytunnel pak choi for best results.
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.
BBC Good Foods. (2020) Pak Choi Recipes. [online] Available at: https://www.bbcgoodfood.com/recipes/collection/pak-choi-recipes [accessed 21/03/24]
