Amaranth or Yin Choi
By Kristian Johnson. A recent graduate of Johns Hopkins University, Kristian is preparing for a career in agriculture and forestry. He is currently undertaking an internship at Wildroots Organic Farm. His goal is to help conserve forests through sustainable farming practices.
It’s easy to condemn the use of synthetic fungicides, insecticides and herbicides by conventional farmers. They, however, are at the mercy of conditions over which they have little to no control. These unsafe toxic compounds provide effective solutions for plant diseases, insect attacks, and weed infestations. Conventional farmers tend to overuse these cheap chemical tools, rather than risk suffering a poor harvest.
An organic farmer, without these potent tools, must instead rely on a deep understanding of the land and the lifecycles of common pests, as well as the characteristics of various plant species. Before deciding what to grow, every farmer must take into account the growing conditions of the upcoming season. Here are some of the challenges of growing in the Hong Kong summer.
Heavy rains (Avg. May to Sept. is 379 mm per month)
Too much water will cause rooting (carrots, radish) and fruiting (tomato) vegetables to crack and also lose much of their flavor. The high clay content prevalent in Hong Kong soils often makes drainage difficult, thereby causing the roots of many plants to die off.
Punishing humidity (Avg. May to Sept. is 81%)
High humidity makes it difficult for many plants to transpire thereby significantly reducing the growth rate of temperate climate species, such as lettuce or spinach. Coupled with warm temperatures, it increases the chances of fungal diseases especially for plants such as zucchini.
High temperatures (Avg. May to Sept. is 28 C)
Plants ill-suited to high temperatures, such as lettuce, wilt or become bitter in summer. Most temperate climate herbs, such as mint or lemon balm, become dormant.
High temperatures also result in prolific weed growth. Competing for sunlight and nutrients, weeds are one of the biggest threats to yield. The Japanese Knotweed is a pernicious invasive species common in Hong Kong. It thrives in warm weather, and has a deep, dense network of rhizomes that spread both vertically (2m deep) and horizontally effectively choking any competition. Removal is nearly impossible as small rhizome fragments can sprout new growth even after 3 years. On organic farms, countless hours are spent manually removing weeds.
Summer temperatures mean there are significantly more harmful insects such as melon flies, flea beetles, and aphids. As consumers, we can select vegetables that grow well during the season, thereby helping conventional farmers reduce their reliance on chemical pesticides. This also ensures we ingest fewer harmful toxic chemicals into our bodies. Here are some of the highly nutritious vegetables that grow well during Hong Kong summers:
- Yardlong beans
- Ceylon spinach
- Morning glory
- Sweet potato leaf
- Sweet corn
原刊於 Go Green 網頁