Latin Name and family: Psidium guajava L. Myrtaceae (Myrtle Family)
Other names: common guava, apple guava, yellow guava, or lemon guava, goiaba (Portuguese) and guayaba (Spanish).
We grow several varieties of guava on our Big Island fruit farm. The most notable ones are the “Indonesian White Guava” and “Ruby Supreme”. We often sell the seeds when they are in season. Check out our website ainaexotics.com or our etsy shop.
Guava fruit Characteristics:
The fruits of the guava tree are fragrant, and globular or ovoid and usually around 2-4 inches (5-10 cm) in diameter and can weigh from a few ounces to (more uncommonly) a pound. There are several varieties, which differ slightly in shape, skin, flesh color, taste, water content etc. Usually, the skin ripens from green to pale yellow and can range from thin skin to thick depending on the variety. Furthermore, the guava flesh can be pink, yellowish and even white. Inside there are many small hard seeds, but again depending on variety some guavas have less seeds.
The most two popular types of Psidium guajava are white and pink guavas. Pink guavas have thicker pulp, more water, and are not as sweet as white guava. And surprisingly white guava is higher in Vitamin C.
Guava Taste and Culinary Uses:
The short shelf life, propensity to pests like the fruit fly and ants, and the amount of seeds in guavas, has directed it’s culinary uses. They aren’t often sold fresh in markets. Instead, they lend really well to processing into juice and pulp for flavoring a large variety of edible goods. Additionally, guavas are very rich in pectin and are often used to make jelly, jams and juices on a commercial scale. To extract the seeds out of guavas, the fruit is often boiled and the seeds are strained, resulting in a rich juice and pulp. The pulp is then used to flavor desserts, chutneys, pies, relishes, bread etc.
Guava harvest and Storage:
While some Psidium guajava may fruit almost year-round, most often fruit matures in the summer. However, in some climates or some trees may fruit a various times of the year or even multiple times a years. You can tell it is time to pick guava when the skin color changes from green to yellow and the fruit begins to give under light pressure of the fingers. Guava has an extremely short shelf life. And is also hard to harvest before bugs have gotten hold of it. For the home grower who doesn’t treat with pesticides, it is best to stay on top of harvesting. Harvest every day and avoid letting over ripe fruit rot on the ground. This encourages higher populations of pests. Storing in the fridge can extend its shelf life a few days, but processing ASAP is preferred.
Guava health benefits:
Guava is very good source of Vitamin C (350 mg per 100 g). The pulp is rich in fiber, and the fruit itself is high in minerals like manganese, vitamin A, folic acid, potassium. Phosphorus, iron, and calcium. Additionally, they contain a high amount of antioxidants. The leaves are also widely used in traditional medicine to treat inflammation as well as digestive disorders.
Guavas are relatively small evergreen trees. They are native to the American tropics but spread and naturalized to many tropical and subtropical areas. In some areas, as in Hawaii, certain varieties are considered a weed and have displaced Native forests. One reason why they are so weedy is because they adapt to a range of soils and can grow almost anywhere where it isn’t too cold. At first guava grows quite slow, but then explodes with a growth spurt and can fruit in as little as 2 years.
Various insects pollinate guava, but the most common insect is the honeybee.
Seedlings are the most commonly used method of propagation for guavas, although guava seed does not reproduce a true to type child plant. Other methods include air layering, grafting and propagation from leafy cuttings. Trees made from vegetative propagation may take 2-3 years to produce fruit (from planting out), while seedling trees may take a little bit longer.
How to save guava seeds
The best method we have found of saving guava seeds, is to remove the flesh from the guava, place in a plastic baggy with water and let ferment a few days. During this process the flesh falls from the seeds.
Germination of guava seeds:
In general, seeds can take 2-12 weeks for germination, but more likely will take around 4-8 weeks. For guavas, plant seeds 1/4-1/2″ deep in moist soil. For best results, use sterile potting media. The soil needs to be warm, ideally between 70-85F. If the soil is much cooler, and the seed germination time will be increased or inhibited all together.
There are several methods you can try to increase germination rates and speed up germination time. But, the most common hurdle is not allowing enough time to pass and not keeping soil moist during the germination period.
scarification with gibberellic acid or sulphuric acid
Paper towel method: Place your guava seed on a wet paper towel and fold the paper towel over the seed. Place the paper towel into a sealable plastic bag. Poke holes into the baggie with a toothpick. Take a plate and add a bit of water to it. Place the baggie on top of the plate. Set the plate in a dark place and wait three weeks. Add water to the plate every four to five days. Additionally, by allowing the seed to remain moist while in a dark place you will help to speed along germination.
Soak the Seeds:
Place the guava seeds in a bowl and cover with 2 to 3 inches of warm water. Cover the bowl and place it in a warm, dark location for two weeks. Add more water if necessary to keep the seeds wet. After two weeks, the seed coating is soft enough for the inner embryo to germinate.
Place the seed-starting tray in a brightly lit, warm location or on a seed heating mat set at 80 degrees Fahrenheit. Guava seeds germinate at temperatures between 70 degrees Fahrenheit and 85 degrees Fahrenheit. If the soil temperature drops below 60 degrees Fahrenheit, the seeds stop growing. The guava seeds germinate slowly, requiring between four and 12 weeks before the tiny sprouts appear above the surface. When the seedlings appear, remove the plastic cover to prevent damping off.
(Essien, E. (2004), Breaking of seed coat dormancy in guava. Trop. Sci., 44: 40–42. doi:10.1002/ts.130, http://onlinelibrary.wiley.com/doi/10.1002/ts.130/abstract)