Beans: Growing Chinese Long beans （长豆）

The Chinese long bean (also known as yardlong bean) belongs to the Legumes family. It is widely eaten in Asia as sambal stir fried vegetable dish that goes with steamed rice. It is not only tasty and protein-rich but also a great 'farmers help' in the area of nitrogen soil enrichment.

Legumes plants host nitrogen fixing properties and help to improve soil fertility. I typically rotate my plot between Asian leafy vegetables which is nitrate hungry and beans which can aid in enriching the nitrogen depleted soil.

Below are the steps needed to plant long beans.

Materials you need

• At least a space of 1.5 m by 0.5m with full sunlight. You will need a garden plot. The following illustration is developed using a green house plot.
• Beans are twining plants. You need to provide support for them to twine on.
• I arranged bamboo poles (at least 5mm diameter) in vertical and horizontal rows forming a vertical fence with small squares. You can use netting with small squares too.
• Overhead netting are placed at the top end of the vertical poles to allow more foliage to flow on top. I bought my netting from Daiso.

Fig. 1 Closed up on poles arrange in vertical and horizontal rows.
 

• I used seeds bought from Thailand (Chiang Rai) but most long bean seeds yield the same result.

Fig. 2 Bag of long bean seeds.

Step 1: Prepare the soil at least 10 to 14 days before seeding. Refer to here if you need help to prepare the soil.

Step 2: Seed about 15 seeds if you are looking at having 10 to 12 seedlings. This is just a general guide of germination rate of 70 to 80%. Your result may varies depend on seed source. I have seen worst case germination rate of 50% (out of 10 seeds only 5 grow into seedlings) for some seed sources. But generally an assumption of 70 to 80% is safe. The best germination rate I have seen can be as high as 90 to 95%.

Dig small holes about 2 to 3 cm apart in the pot, place the seeds in the holes and cover them. Water well and place in sunny place. It takes typically about 10 to 14 days for seeds to grow into seedlings suitable for transplant (about 10 to 15 cm height). It is important to space out the seeds so that it will be easier to remove the seedlings individually with enough soil wrapped around the roots for best transplant success rate.

 

Fig. 3 After 5 days seedlings emerging from soil (above) and

ready for transplant on day 10 (below)

 

Step 3: Transplant the seedlings to the actual location. In this case just directly next to the fencing support as shown below.

Fig. 4 The Long Bean Plants 3 to 4 weeks after seeding

(~ 1 to 2 weeks after transplant) 

 

You need to apply organic fertilizer once a week. You need about 10 pellets or 1/8 of 200ml cup per plant.

Dig hole at least 5 to 10 cm away from the stem, apply the fertilizer and cover it. Do not apply too near the stem or apply too much fertilizer. The plant will die due to sudden surge of 'salt' content in the soil. The roots will rot and the leaves will wither.

Step 4: The long bean plants will twine thier way up the support. You can help them along initially by twinning the end to the support if they failed to find the way themselves. Below is a picture of the plants after 7 weeks. Notice that the netting on top of the vertical support is now overflow with long beans foliage.

 

Fig. 5 Long Bean Plants on week 7

Step 5: If you want more beans to form, from time to time trim off about 10% of the foliages. By week 8 after transplant, the plants should be full of beans. It is harvest time!

Fig. 6 Long Beans hanging from the plants (left).

Closed up on the long beans(right).

 

From time to time, you may wish to allow some beans to mature on the plant to provide seeds for next planting.

Fig. 7 Keeping beans on the bean stalks to slowly mature and provide seeds for next planting cycle. Choose fat and long beans for best quality seeds. The bean shown above is about 2.5 ft long.