super soil

We tried growing radishes in the Yale-NUS College Farm. They grew out to be in a really sorry state – small and shrunken. We have less than a metre of soil on the farm, and concluded that radishes needed more soil depth. 

However, we went to Mdm Kamisah’s rooftop community garden and saw rows of huge, white radishes sprouting out of the soil, with only about half a metre of soil depth. I realized then that (for radishes at least), the depth is only one aspect influencing plant health. Soil quality, meaning the minerals and microbial activity inside the soil, is integral. Chingwei, founder of Project Blackgold and part of the Foodscape Collective, mentioned a story of her friend who bought a piece of land in Dakota, USA, and wanted to use it to grow crops. His crops were weak, and he sent a sample of the soil to the lab, and found that it was 95% sand. He decided to compost, and added compost to the soil over time. He sent another sample, and it also reported 95% sand. However, his crops were flourishing this time. This showed Chingwei that plants really need the relevant minerals and microbial activity in the soil, on top of just the composition of sand, silt, and clay in soil. Each plant has different requirements (for example, chilis do not really like wet soil, radishes need soft, peat soil, spinach can be mixed with flour?), and Chingwei advised against “feeding them too much” to attract pests as well. It has been an eye-opening experience how to tend to particular plants in particular climates. Sometimes, plants can also help each other out. The Three Sisters, for example, squash provides shelter for the ground so they do not get solarized, beans fix nitrogen in the soil, corn are sturdy enough to provide support for the climbing beans. 

On the campus farm, much of the soil is yellowish, hard clay, instead of fine, black soil that contains enough air pockets for beneficial aerobic microorganisms to break down matter (pathogens are mostly anaerobic?). We decided to do more composting. We learned that a 2-3 carbon : 1 nitrogen ratio is needed for a compost, so we managed to get dried leaves and sawdust that make up our carbon pile, and nitrogen from fruit peels and vegetables coming in from students and faculty. Our compost pile is shrinking over time and rising in temperature due to microbial activity, and hopefully we can use our compost to germinate seeds in the future.