Star fruit, or Carambola, is gaining popularity in Florida. While the sunshine state is typically known for its oranges, a researcher from Florida International University is showing how cover crops can help star fruit farms be sustainable.

Researcher Ariel Freidenreich says that tropical fruits have been widely cultivated in the Miami-Dade region.

Currently, the Arkin variety is the most popular. Expanding to sweeter tropical fruits is becoming more prominent in Florida.

Creating sustainable growing conditions for star fruit

"For this reason, it is vital that sustainable farming practices are applied to these systems to ensure healthy soils and economically viable fruit production," she adds.

Finding a variety of crops that grow in the state is important for several reasons, research says.

The research involves cover crops. This means that crops are grown but not to be harvested. Rather, they are used to add to soil health. Specifically, the team looked at two different cover crops - sunn hemp and velvet bean. The purpose of doing so is to take nitrogen from the air and metabolize it into plant nutrients.

The use of these crops made sure that star fruit trees grew in healthy conditions without "the addition of synthetic inputs". Additionally, research thus far has shown that hemp can help star fruit remain resilient. Star fruit is sensitive to wind and some cover crops act as a windbreak to prevent damage.

Futhermore, "star fruit is truly tropical and can be sensitive to cool temperatures in the winter months in subtropical south Florida," adds Freidenreich.

"Cover crop mulches might insulate the roots of carambola trees."

Increasing the diversity of fruit in Florida could help combat the bad effects of diseases like citrus greening, explains Freidenreich.

"The disease destroys the production, appearance, and economic value of citrus trees and their fruit, and there is no cure. Similarly, laurel wilt has been greatly impacting the avocado industry in south Florida. Different crops are being planted to replace avocado groves," she details.

Not only does producing more star fruit diversify crops, but it also diversifies the income stream for farmers. Having diverse crops can function as risk management for farmers, says Freidenreich.

More details about the research

The team of researchers are currently still conducting tests on a certified organic farm. They chose this as the site of investigation because it is designed to help farmers transitioning to organic farming.

Soil at the research site is "rock-plowed limestone with little natural organic matter content," explains Freidenreich.

Therefore, improving soil organic matter through cover crops is essential.

"It should also improve soil structure and microbial interaction. We expect fruit yield improvement over time. South Florida has a subtropical climate, so hot and humid weather inspires quick turn over for organic matter degradation. Continually adding these treatments should have positive benefits season to season. The cover crops can be great for weed suppression in the growing season and after termination."