Tropical Fruits You Can Grow Economically in Hardiness Zones 8 & 9:
In a previous article I proved one can grow just about any tropical fruit/plant in temperate zones 8 & 9 as long as the plants can be kept/pruned/bonsaied at small enough size to fit inside a greenhouse during the winter AND provided one can afford the heating & lighting bills. This article is to separate out the plants that will die without expensive heating/lighting and those that will do just fine with minimal to average costs involved.
Generally, most woody trunk/stemmed plants will survive temperatures as low as 7°C/44.5°F throughout the winter and with moderate lighting. Avocados, starfruit, mangoes, citrus, specialty figs, etc… will fare well IF you can maintain a minimum room temperature of 10°C/50°F. Plants with soft trunks/stems such as papayas, bananas, sweet potatoes, moringa, Malabar spinach, salad tree, dragon fruit, pineapple, granadilla, etc… will NOT survive in such conditions. How would I know? Well, this mild winter of 2023/2024 (in Vancouver) had proven that without adequate heating/lighting even in relatively balmy December weather, all the soft stem plants mentioned above have died in my greenhouses.
To save money and to prove that my greenhouse setups can be cost effective, I turned off my 200watt usage grow lights (using just the low wattage lights) and lowered my heat settings from 10°C/50°F night and 16°C/61°F day to a constant 7.5°C/45.5°F throughout. Within a month of these conditions inside my greenhouse the soft trunk plants started dying. It was a pricey experiment but at least it will help others not to waste money purchasing these species from nurseries if they live in cold environments and don’t want to bring the plants inside or spend tons of money on their electric bills. Plants that I do recommend bringing indoors are valuable ones like moringa, granadilla & dragon fruit. They are not only healthy, expensive to buy at the grocers, they are also visually appealing indoors & require less space.
As for the woody trunk tropical plants mentioned earlier, all except the mangoes survived. I found that citrus and heat loving fig species tolerated even colder conditions. In the future I will definitely put the minimum setting to 10°C/50°F all day just to be safe. I placed most of my citrus and non-freeze tolerant figs inside my other greenhouse which only uses sunlight and almost no heating except for some nighttime incandescent Christmas string lights & a 5-gallon bucket of water heated with a small aquarium heater + heat mat.
To summarize, one should be wary of the kind of plants they purchase from nurseries… chances are a good majority of them will not make it through the winter. Just because they sell them in temperate regions doesn’t mean they’re meant for you to grow… it’s meant for the nurseries to make money. Most specialty nurseries will also carry cold-tolerant species of tropical plants but the vast majority of the fruits from these plants taste awful… so don’t bother unless you just want them for the looks. Choose wisely on what you want to grow in your garden, do your research on how to properly take care of them and things will grow great!
