Fresh and raw Chinese pak choi

How to Grow Pak Choi

Pak Choi, also called Bok Choi, is a cool-season crop grown for its delicious leaves that can be eaten fresh in salads, cooked in stir fries or lightly steamed. 

Sowing 

Because pak choi is a cool-season crop, it should be sown in early spring, autumn and in the winter. When growing pak choi in your S-Series Mini Greenhouse, it’s important not to keep the tray too warm or have the grow lights on for too many hours. Light for more than 10 hours and temperatures greater than 24°C will cause it to bolt, flower, and set seed. As bolting equals the end of harvest, keep well within those limits.  The ideal growing temperature is 7-21°C and less than 8 hours of direct light. The seeds tend to germinate in 7-14 days.

Pak choi is fairly easy to grow from seed and can be directly sown or transplanted later. It’s a perfect crop to sow in your Sprout as it can stay in there till it matures or be transplanted outside. 

Fill a tray with compost and water it. Sow the seeds about 5cm apart and sprinkle 2cm of compost on top. Press down slightly to make sure that the seeds are in good contact with the compost, and carefully water again. 

Keep the soil evenly moist until seeds germinate. If they dry out, it’s unlikely they will germinate at all. This can be aided with a plastic dome over the tray but it is not a must! As a general rule, the colder the soil the less moisture you need.

Plant care 

Keep the soil well watered throughout the growing season to avoid bolting and ensure good flavour. Also, make sure to keep them fed throughout the growing season. 

Growing options 

You can choose from one of the growing options below or do a combination of 2, 3 or 4! 

  1. Baby Leaves: Thin the seedlings to 7.5-10cm apart and then start harvesting directly from your tray when the leaves are big enough. If you pick one or two leaves of each plant from the outside, rather than the whole plant, it should keep on growing for a while and give you a few harvests! 
  2. Grow till maturity in your S-Series Mini Greenhouse: When the seedlings have emerged, thin them to 15-20cm apart. This can be done by cutting the rejects with scissors (eat them in a salad!) or carefully using a stick/pencil to loosen the soil and lift the seedling up by its leaves and transplant to elsewhere. Make sure they are big enough to handle before you set out to do this. The compost will only have enough nutrients for a few weeks so you will have to feed the plants with an organic fertiliser throughout the growing season. 
  3. Plant outside: When the seedlings have developed their true set of leaves (not the first set appearing but the second set) they can be transplanted out into your garden. Space them 20cm apart. If you have problems with slugs, keep them in your S-Series a little longer. A bigger plant can resist a slug attack much better! When planting outside it is best to make sure that your soil is great before planting, by adding well rotten manure or other organic material so that it’s full of nutrients for your plants. When transplanting seedlings, ideally plant out early morning or evening and/or on an overcast day. Avoid planting at peak sun times or on windy days as this can cause sun or windburn which can lead to death! 
  4. Container Grown: Pak Choi grows well in containers outside, but as it is heat-sensitive, move containers into the shade on warm days and keep in mind that containers will warm quicker than garden soil in spring, so keep it well watered. Also, keep in mind that the compost will only have enough nutrients for a few weeks so you will have to feed the plants with an organic fertiliser throughout the growing season.

Harvesting 

Pak Choi leaves can be harvested as soon as they are big enough to eat and it is up to you if you like the small baby leaves for a salad or larger ones for cooking!  Baby leaves are ready to harvest in 30 days, while semi-mature to full-sized heads take 45–75 days.  Baby leaves can be picked one at a time, whilst mature heads are harvested by cutting the whole head at ground level. In any case, finish harvesting before the weather gets hot, as it will make the leaves tough and strongly flavoured. It will also make the plant bolt. 

Watch out! 

Flea beetles are the biggest problem leaving the leaves covered in small holes and damaged areas turning brown. They should however not be a problem in your S-Series. When planting out, seedlings are particularly susceptible. The best solution is to grow plants under a horticultural fleece and keep the soil moist. Also, keep the plants well fed to help the crop outgrow the pest! Slugs can also be a problem when planting out so it may be better to keep them in your mini-greenhouse for longer. 

Pro Tip

Do not let Pak Choi bolt. Instead, harvest quickly as it will keep in your fridge in the vegetable compartment for up to 4 weeks. You can also blanch Pak choi and freeze for 3 months. Perfect for a quick stir fry!

Nerdy facts

The botanical name is Brassica rapa subsp. chinensis

Recommended Varieties

Here are two great varieties but there are many more fantastic varieties to choose from!

‘Red Choi’ is a gorgeous purple-red leaf variety with green undersides and bright green stems. 

‘Glacier’ is an F1 hybrid bred to cope with British weather! It has excellent resistance to bolting during hot weather and also has a good cold tolerance.