Tops of the crops: What does it take to grow the tastiest tomatoes?

Juicy tomatoes bursting with flavour and sunshine are the star of any dish. As a firm favourite among Hong Kong consumers, the fruit is a key crop for our Restore farmers. 

But what does it take to produce a healthy, delicious tomato? 

From soil quality to the availability of water and sunlight, it is vital to understand the nuances of each environment so our farmers can implement the most effective practices. We adopt different approaches with each of our Restore farms to maximise improvements in soil health. The transition from traditional to regenerative practices takes time, but with the help of our soil experts at Homeland Green and our diligent Technical Assistance Providers (TAPs) collecting valuable data, we have already seen changes. 

This year’s grantees have been keen to try companion planting to reap benefits, including improved pollination and pest control and covering bare soil to reduce moisture loss. Early observations at AuLaw Organic Farm have shown their plot could not support tomato growth and fertilisation, so we recommended they apply compost tea to build a healthy fungal-to-bacterial ratio. After only two weeks of regularly using the compost, coupled with planting basil on the side (a popular companion choice for tomatoes), the leaves of the tomato plants are visibly more nourished and suffer less damage from pests (Fig. 1 shows before (left) and after (right).  

Fig. 1

Unlike AuLaw’s farm, Sangwoodgoon has limited onsite infrastructure and cannot make its own compost tea. Instead, they applied mushroom substrates to control weeds, added their farm-made compost, raw nut pulps, and included Indian Lettuce as a companion plant. The results of this combination speak for themselves (Fig. 2) - the plants have grown taller and stronger, with flowers ready for pollination. Furthermore, data collected in December indicated a higher ‘Brix’ level (dissolved sugar content), giving plants higher resistance to harmful insects chewing on their leaves and fruit.

Fig. 2

Due to the current degradation of Hong Kong’s soil, it will take time to rebuild above and below-ground microbiology. But there are measures our grantees can take to give their tomatoes the best chance of success before they have even entered the soil. Just as a baby needs nourishment in the womb, we can prevent disease and other issues further down the line by strengthening plants at the germination stage. A working example is the tomatoes at Eva’s Farm, which have been suffering from bacterial wilt – a contagious disease that spreads to other crops. To promote healthy growth, we recommend Eva soaks the seeds with Trichoderma water, which she can only apply before the plants reach the seedling stage.

Eva’s tomato field under attack

Asymmetric or curly leaves and uneven fruit sizes are all indicators of malnutrition. Applying nutrient amendments is an effective way to improve plant health, but the right combination of substances is critical. For example, when making fish hydrolysis, a common nutrient amendment, zinc-rich kombu must be included to prevent leaf discoloration. Adding the micronutrient Boron is also encouraged as it supports cell wall formation and functional integrity of a plant.

Farmer Pat Fan from Cham Shan has learned these practices as a beneficiary of the Restore fund, and has implemented them along with mulching and composting to successfully grow healthy tomatoes with no bacterial wilt.

Next time you order spaghetti marinara or a caprese salad, consider what lengths farmers need to go to for you to enjoy this juicy fruit.