Thai White Guava, a flavorful tropical fruit, is easy to cultivate both in the ground and in containers. Gardening expert Melissa Strauss provides insights on how to grow and maintain the delightful Thai White variety, a popular choice at farmers’ markets.

Thai White guava is distinguished by its glossy, broad green leaves and round, textured green fruit.

Thai White Guava Tree Overview

• Plant Type: Tropical Evergreen
• Family: Myrtaceae
• Genus: Psidium
• Species: Guajava
• Native Area: Mexico, Central America, the Caribbean, South America
• Exposure: Full sun
• Height: Up to 20 feet
• Watering Requirements: Moderate
• Pests & Diseases: Thrips, mealybugs, aphids, anthracnose, algal leaf spot, peralotiopsis, stylar end rot, wilt
• Maintenance: Low
• Soil Type: Sandy, loamy, rocky, muck, acidic
• Hardiness Zone: 9-11

This resilient small tree adds beauty to any landscape, thriving outdoors only in USDA hardiness zones 9-11. In cooler climates, it serves well as a container or patio plant.

Guavas have been cultivated for around 5,000 years in Peru. Spanish and Portuguese explorers brought the guava to Florida and Europe, eventually spreading it to Asia and India.

Legend has it that guava fruit was once inedible until a compassionate young boy prayed for the gods to make it edible for a hungry beggar. The gods granted his wish, endowing the fruit with the deliciously sweet and tangy flavor we cherish today.

Key Features of ‘Thai White’ Guava Trees

• The Thai White guava is a medium-sized evergreen tree that can reach heights of 15 to 20 feet if left unpruned. To manage its size and make harvesting easier, you can prune it as needed.
• The fruit is green on the outside with white flesh inside, offering higher sugar, vitamin C, and fiber content compared to pink guava. It also contains more seeds, which contributes to its fibrous texture. The entire fruit, including the peel, is edible.
• The National Library of Medicine notes that consuming the fruit with the peel provides significant health benefits. It can help reduce blood glucose levels and triglycerides, making it a valuable addition to a nutritious diet.
• Visually appealing, the ‘Thai White’ guava tree enhances any tropical landscape. It typically features one or two central trunks and a broad, umbrella-shaped canopy. The leaves are large, medium green, and have noticeable veining.

Origin of Thai White Guava

Guavas originally come from Central and South America as well as the Caribbean. In the 17th century, Portuguese explorers introduced the white guava to Asia, where it quickly gained popularity as a favored fruit. In Thailand, the fruit is called “farang,” a term historically used to refer to foreign individuals of European descent.

Planting

The ideal time to plant your Thai White guava is in the spring or early summer, as the tree is in an active growth phase and will establish itself more quickly. If you’re growing it in a container, you can re-pot it at any time of the year. However, remember to bring the plant indoors if temperatures fall below freezing.

In certain regions of North America, where the tree is considered invasive, it’s best to keep it in a container. To encourage robust root growth, use loose soil and dig a hole three times as deep and wide as the root ball. Although this might seem excessive, it provides the ideal environment for root development.

Fill the hole with soil up to the level of the root ball, ensuring that the top of the root ball is even with the surrounding ground. Generally, soil amendments aren’t necessary, so just fill in the hole, press down the soil firmly, and water it thoroughly.

Since guava roots can spread extensively beyond the drip line, it’s important to plant it at a sufficient distance from your home, buildings, or concrete surfaces to avoid any potential damage.

Tips for Growing Guava Trees from Seed

‘Thai White’ guava trees are typically propagated through grafting, as growing them from seed does not guarantee the same characteristics as the parent plant. If you’re up for a gardening adventure, you can grow them from seed, but be prepared for a long wait: it usually takes six to eight years for these trees to produce fruit when started from seed.

To grow guava from seed:

1. Choose Fresh Seeds: Extract seeds from fully ripe fruit, as their viability diminishes rapidly once removed. Avoid using old seeds.
2. Soak Seeds: Soak the seeds overnight, or up to two weeks, before planting.
3. Prepare Potting Medium: In a medium-sized nursery pot, use a soilless potting mix. Press one seed into the mix and lightly cover it.
4. Provide Warmth: Guava seeds require warmth to germinate. Place the pot in a warm location, maintaining a temperature above 65°F (18°C). A heating mat can help if needed.
5. Maintain Moisture: Keep the soil consistently moist but not waterlogged during the germination period. Be patient, as germination can take anywhere from four to 12 weeks.

Cultivating Thai White Guava Trees

Thai White guava trees are known for their fast growth and ease of care. With proper attention, a mature tree can yield several dozen pounds of fruit. If grown from seed, expect a maturity period of about eight years, but if propagated from cuttings, fruit production will occur much sooner.

Light Requirements : For optimal fruit production, ensure the guava tree receives at least six hours of sunlight daily, though eight to ten hours is ideal. While it can tolerate partial shade, the tree will produce fewer flowers and fruits in such conditions. If growing in a container, place it in the sunniest spot and bring it indoors only when temperatures drop. Indoor growth requires a bright window.

Watering Needs : Initially, the guava sapling will need frequent watering—every other day for the first week—to establish its roots. Following this, water twice a week throughout the growing season. Ensure deep watering to promote robust root growth, allowing the soil to dry out between waterings to prevent fungal issues. Established trees are moderately drought-tolerant but still require watering during dry spells. Avoid overwatering to prevent root rot, characterized by yellowing leaves and a musty smell. A lack of water during drought can cause the tree to go dormant, affecting fruit production.

Soil Preferences : Guavas are adaptable to various soil types, including sandy, loamy, rocky, and muck soils, as long as there is good drainage. The crucial factor is soil pH; an acidic pH of 4.5-7 is ideal for optimal iron availability. In less acidic soils, supplement with chelated iron. Plant in loose soil to accommodate the tree’s shallow root system, especially if propagated by air layering.

Temperature and Humidity : This tropical tree thrives in warm climates and prefers temperatures above 60°F (16°C). Exposure to temperatures below freezing can cause dormancy or even death in young trees, while mature trees tolerate brief cold spells but may suffer foliage damage. Container growing is advisable in areas with freezing winters. Maintain moderate humidity levels (40-50%) to prevent growth inhibition or fungal diseases. Growing in a greenhouse can help control humidity levels.

Fertilizing : Thai White guava trees require regular fertilization, particularly in their first year. Start with monthly applications of 1/4 pound, increasing to one pound by the fourth month. In subsequent years, fertilize three to four times annually, adhering to the recommended amounts on your fertilizer packaging, without exceeding 20 pounds per year. Use a balanced fertilizer with added magnesium, such as 10-10-10-4 or 6-6-6-2, and stop feeding during the winter dormant period.

Common Problems

Guavas are prone to attracting pests due to their high sugar content and sweet aroma. Additionally, the high humidity levels ideal for their growth can increase their susceptibility to fungal diseases.

Pests
Guavas can attract various pests, including fruit flies, whiteflies, scales, guava moths, and red-banded thrips. To manage these pests, use a strong water spray to dislodge them and hand-pick moth eggs. For scale insects, apply a cotton swab dipped in 70% alcohol to remove them.

Maintaining a healthy plant through proper watering and fertilizing can enhance its resistance to pest issues. For additional protection, use organza bags to cover individual fruits, preventing pest damage without the need for pesticides, which is beneficial for both you and pollinators.

Diseases
Tropical guava trees, thriving in warm and humid climates, are susceptible to fungal diseases such as anthracnose, stylar end rot, wilt, and pestalotiopsis (guava scab). To mitigate these issues, remove and discard affected fruit to limit disease spread. Avoid consuming damaged fruit.

To prevent diseases like algal leaf rot, ensure good airflow around your plant by thinning its interior. Applying preventive anti-fungal sprays containing sulfur can help manage fungal problems before they become severe.

Iron Deficiency
Guavas require ample iron, and iron deficiency, or chlorosis, can occur, particularly in calcareous or alkaline soils. Symptoms include yellowing between leaf veins, while the veins themselves remain green, and deformed or undersized fruit.

Prevent iron deficiency by amending the soil with organic material to reduce pH levels. For soils that remain alkaline, use iron chelates designed for such conditions to ensure adequate iron availability to the plant.

Maintenance

To keep your Thai White guava in top condition, regular maintenance is essential. Apply mulch annually to protect and insulate the tree’s shallow root system. Additionally, proper pruning helps manage the tree’s size and encourages optimal fruit production.

Young Trees : In the first year, trim your guava to a height of about one to two feet. This promotes the growth of lateral branches, bringing the fruit closer to the ground.

As the tree develops, choose three or four strong branches to serve as the main structure. Allow these to grow to around two feet before pinching the tips to encourage further branching.

Once the second tier of branches reaches two feet, tip them as well. This will result in a tree that remains lower to the ground with ample branches to support a bountiful harvest.

Remove any waterspouts—branches that grow straight up and do not bear fruit—as they consume energy without producing results.

Mature Trees : Pruning should be guided by your desired tree size. For container-grown trees, maintain a height of up to six feet. This size is manageable, facilitates fruiting, and makes indoor wintering easier.

To maintain a smaller size, make cuts closer to the trunk and tip branches more compactly. For trees planted in the ground, aim to keep them around 12 feet tall. Larger trees can grow up to 20 feet, making fruit harvesting more challenging.

A height of 10-12 feet is ideal for easy harvesting and protection from strong winds. Regularly prune crossing branches to improve airflow, reduce the risk of fungal diseases, and enhance branch strength.

Propagation : While Thai White guava can be grown from seeds, which will produce true-to-type fruit, it requires up to eight years to bear fruit. Grafting is an option, but air layering and cuttings are the preferred methods for quicker fruit production.

Cuttings : For propagation via cuttings, select healthy terminal branches that are six to eight inches long and recently mature, ensuring they have two or more leaves. Optionally, apply rooting hormone to speed up the rooting process. Cut the branches at an angle to maximize the surface area for roots.

Plant the cuttings in a sterile, moist potting mix. Keep the soil consistently moist and place the cuttings in a warm location with bright, indirect light to facilitate rooting.

Air Layering : Air layering is an effective method for propagating guavas, though it results in a shallower root system. To ensure strong root development, prepare the soil by loosening it well and watering deeply.

Select a healthy branch with desirable growth. About 12-18 inches from the end, make two parallel scores in the bark about an inch apart, then remove the bark between the cuts.

Cover this area with moist peat or sphagnum moss, and wrap it with plastic wrap or an air-layering ball to keep the moss in place.

Check the roots every two to three weeks to monitor their growth. Be cautious when unwrapping to avoid damaging the delicate new roots.

Once the roots are well-developed, cut the branch just behind the root ball. For better survival, start by planting it in a container to allow the roots to strengthen further before planting it in the ground. Initially, keep the plant out of direct sunlight until it shows new growth, then move it to a sunny spot.

Harvesting and Storage

To harvest Thai White guavas, pick the fruits while they are still firm and green. They are typically collected before they ripen fully. The guavas will continue to ripen off the tree, and they will do so more quickly if left at room temperature rather than in the refrigerator.

For extended storage, keep the guavas in the refrigerator. You can also freeze them for longer preservation. Additionally, guavas can be used to make various products like sweet pastes, syrups, and jams.

Frequently Asked Questions

How long does it take for guava fruits to ripen?
Guava trees typically flower in the spring, with the fruits requiring between 90 to 150 days to fully ripen, depending on the weather conditions.

Is guava safe for pets?
Yes, guava is safe for pets to consume in moderation. However, ensure you only offer it as an occasional treat.

Is ‘Thai White’ self-pollinating?
Yes, the Thai White guava tree is self-pollinating and can produce fruit on its own. Planting an additional tree nearby can enhance fruit yield.