Upo (Lagenaria siceraria)

About Upo

Upo (Lagenaria siceraria) is the everyday gourd of Filipino home cooking — a mild, versatile, fast-growing vine vegetable that appears in ginisa, soups, and stews across the Philippines with such frequency that it barely registers as a distinct ingredient, instead serving as the quiet workhorse base that absorbs the flavors of garlic, onion, shrimp paste, and whatever protein the cook has on hand.

The vine is a vigorous, fast-climbing cucurbit that can grow 5-10 meters in a single season, rapidly covering trellises, fences, and arbors with large, soft, rounded leaves. The tendrils grip any available support, making upo an excellent candidate for vertical gardening in space-limited urban areas. When grown on an overhead trellis (banggerahan or paras), the fruit hangs freely and develops into the long, straight, club-shaped gourds preferred by Filipino cooks — typically 20-40 cm long and 8-12 cm in diameter at harvest.

What makes upo botanically remarkable is its status as one of humanity's oldest cultivated plants. Archaeological evidence dates bottle gourd cultivation to over 10,000 years ago — predating rice, corn, and wheat. The original purpose was not food but technology: the mature gourd, with its hard, waterproof shell, served as a container, water vessel, and float. The young fruit's use as food came later, making upo one of the rare plants domesticated first for its industrial utility and only secondarily for eating.

For Metro Manila urban growers, upo is among the most rewarding vine vegetables to grow. It germinates fast (5-10 days), grows explosively in the Philippine heat, and begins producing harvestable fruit within 60-75 days. A single well-trellised vine can yield 10-20 fruit over 3-4 months, providing a steady supply for the kitchen from a minimal footprint of ground space.

History & Discovery

Lagenaria siceraria originated in Africa, where wild populations still exist in southern Africa and Zimbabwe. The species was formally described by Molina in 1782, though it had been cultivated on every inhabited continent for millennia before scientific classification. The bottle gourd holds a unique distinction in agricultural history: it is the only cultivated plant known to have been present in both the Old World and the New World before Columbus — archaeological remains dating to 8,000-10,000 years ago have been found in both Africa and the Americas.

How the gourd crossed the Atlantic Ocean before human seafaring remains a topic of scientific debate. The leading hypothesis, supported by genetic analysis, is that wild gourds floated across the ocean from Africa to the Americas — the mature fruit's hard, waterproof shell and buoyancy make this plausible, with viable seeds surviving months of saltwater immersion. This natural dispersal was followed by independent domestication on each continent.

In the Philippines, the bottle gourd arrived via Austronesian migration and Indian Ocean trade routes, establishing itself in Filipino agriculture well before the Spanish colonial period. The Tagalog name "upo" and regional names — tabungaw (Ilocano), upo (Kapampangan), kukunubong (Visayan) — reflect indigenous linguistic roots. The mature dried gourd was traditionally used as a water dipper (tabo) and storage container in rural areas, though this use has largely been replaced by plastic.

How to Plant Upo in the Philippines

Upo is grown from seed — direct-sown or started in seedling trays for transplanting. Seeds are widely available from agricultural supply stores and even wet markets. The vine establishes quickly in Philippine heat and begins fruiting within 60-75 days.

Propagation Steps

1. Pre-soak seeds: Soak upo seeds in warm water for 12-24 hours to soften the hard coat. Alternatively, nick the pointed end with a nail file. This reduces germination time from 10-14 days to 5-7 days.
2. Prepare planting holes: Dig holes 30 cm wide and deep, spaced 1-2 meters apart along the base of your trellis. Mix soil with generous organic compost or aged animal manure — upo is a heavy feeder that rewards rich soil.
3. Sow seeds: Plant 2-3 seeds per hole, 2-3 cm deep, pointed end facing down. Water thoroughly. Thin to the strongest seedling after the first true leaves emerge.
4. Install trellis before climbing begins: Set up a sturdy bamboo A-frame, overhead arbor, or wire/nylon net trellis before the vine starts climbing (around 2-3 weeks after germination). The trellis must support heavy fruit — each upo can weigh 1-5 kg. Overhead trellises produce the straightest fruit.
5. Train the vine: Guide the young vine toward the trellis and loosely tie the main stem to the support with soft ties. Once the tendrils engage, the vine climbs independently. Redirect wayward branches as needed.
6. Water consistently: Water daily or every other day — upo is a moisture-loving crop. Insufficient water causes bitter fruit, poor set, and blossom-end rot. Mulch the base to retain soil moisture. Drip irrigation at the root zone is ideal.
7. Harvest young: Pick fruit when 20-35 cm long and the skin is easily punctured by a thumbnail. Overmature fruit becomes hard-shelled, fibrous, and potentially bitter. Cut stems with shears — don't twist, which damages the vine.

Best Planting Season

Upo can be planted year-round in the Philippines but performs best when sown at the onset of the wet season (June-July) or during the cool dry months (October-December). Avoid peak dry-season planting (March-May) unless consistent irrigation is available — heat stress combined with drought produces bitter fruit.

Care Guide

Sunlight

Upo requires full sun — at least 6-8 hours of direct sunlight daily. The vine grows toward light and flowers prolifically in full-sun positions. Shaded vines produce excessive foliage with few flowers and fruit. In urban settings, the south- and west-facing walls and rooftops of Manila offer ideal trellising locations.

Water

Upo is a thirsty crop — water daily or every other day during active growth and fruiting. The fruit is 96% water, so consistent moisture directly determines yield and quality. Drought-stressed plants produce bitter-tasting fruit due to accumulated cucurbitacins. Mulch the root zone with 5-8 cm of organic material to conserve moisture. Avoid wetting leaves late in the day, which promotes fungal disease.

Soil

Rich, well-draining loamy soil with abundant organic matter is ideal. Upo is a heavy feeder that depletes soil nutrients quickly during its rapid growth phase. Amend soil generously with compost or aged manure before planting. Optimal pH is 6.0-7.0. Raised beds with custom soil mix work well in Manila's urban environment, where native soil is often compacted or nutrient-poor.

Humidity & Temperature

Upo thrives in the Philippines' tropical heat and humidity — 25-35°C with 70-85% humidity. The vine grows fastest during warm, humid conditions and slows during cooler months. Upo cannot tolerate frost (irrelevant in the Philippines) and shows reduced growth below 18°C. High humidity promotes powdery and downy mildew — ensure good air circulation through proper vine spacing and trellis design.

Fertilizer

Upo is a heavy feeder that benefits from frequent fertilization during its rapid 3-4 month growing cycle. Apply complete fertilizer (14-14-14) at 50-75 g per plant every 2 weeks during vegetative growth. Once flowering and fruiting begin, switch to a potassium-rich formula (e.g., 0-0-60 muriate of potash) to improve fruit quality. Side-dress with compost or aged manure every 3-4 weeks. Foliar feeding with dilute fish emulsion accelerates vine growth.

Pruning & Training

Prune lateral branches below the trellis level to direct energy to the main growing tip and upper canopy where fruit develops. Once the vine reaches the top of the trellis, allow it to spread horizontally. Remove yellowing leaves and spent fruit promptly to reduce disease pressure and redirect energy to new fruit set. Some growers pinch the growing tip after 3-4 meters to encourage lateral branching and more fruiting nodes.

Growing Medium Options

Edible Uses & Nutrition

Upo is the definition of a utility vegetable — mild, absorbent, and versatile, it takes on the flavor of whatever it is cooked with. This very mildness is its strength in Filipino cooking, where it serves as a neutral base that stretches meals, adds bulk and moisture to dishes, and provides a soft, comforting texture in soups and stews.

Edible Parts

• Young fruit (primary): Peeled and sliced — the main edible part used in cooking
• Young leaves and tendrils: Edible — sautéed (ginisa) or added to soups as a leafy green
• Seeds (young): Edible when the fruit is harvested young; mature seeds are hard and inedible

Culinary Uses in Filipino Cooking

• Ginisang upo: The classic preparation — upo sautéed with garlic, onion, and either ground pork, shrimp, or dried hibi (small shrimp). Simple, everyday, and deeply Filipino.
• Misua with upo: Thin wheat noodles (misua) in a light broth with upo and ground pork or patola — a traditional postpartum recovery dish for new mothers
• Tinolang manok with upo: Chicken ginger soup using upo slices as the vegetable component, especially when green papaya is unavailable
• Upo con hibi: Stewed upo with dried shrimp — a home-cooking staple that stretches budget ingredients into a flavorful side dish
• Chopsuey and pancit: Sliced upo added to mixed vegetable stir-fries and noodle dishes for volume and soft texture
• Sabaw (broth/soup): Upo in clear broth with fish or pork — a simple, nourishing soup served with rice
• Lumpia filling: Grated upo mixed into lumpiang shanghai or fresh lumpia fillings for added moisture

Nutritional Information

Per 100 g of raw upo (USDA FoodData Central — white-flowered gourd/calabash):

Upo is extremely low in calories (14 kcal per 100 g) and nearly all water — making it an excellent diet food. It provides modest amounts of vitamin C, zinc, and B vitamins. In Filipino folk medicine, upo is considered a "cooling" food recommended during fever, urinary tract issues, and hot weather. Its bland, soft texture makes it one of the first vegetables introduced to Filipino babies during weaning.

Air Quality & Oxygen

As a fast-growing vine with large, broad leaves, upo provides seasonal air quality benefits and effective green coverage for urban spaces. When grown on overhead trellises, upo creates a functional green canopy that shades the ground below, reducing surface temperature by 3-5°C — useful for cooling patios, walkways, and even vehicle parking areas in Metro Manila's heat.

The vine's rapid growth rate means it produces significant oxygen during its 3-4 month growing season. While this is seasonal (upo is an annual), successive plantings can maintain green coverage year-round. The large leaves also intercept airborne dust and particulates, contributing to localized air quality improvement in urban garden settings.

Toxicity & Safety

Humans — Normal fruit (SAFE): Young, non-bitter upo fruit is safe to eat raw or cooked. The young leaves and tendrils are also edible.

Humans — Bitter fruit (TOXIC): Upo fruit that tastes bitter contains elevated levels of cucurbitacin E — a toxic triterpenoid compound. Consuming bitter upo causes severe gastrointestinal distress (nausea, vomiting, abdominal cramps, bloody diarrhea) and in rare cases can be life-threatening. Cases of cucurbitacin poisoning from bitter bottle gourd have been documented in the Philippines and India. Always taste a small piece of raw upo before cooking — if it is bitter, discard the entire fruit. Cooking does not destroy cucurbitacins.

Pets: Young, non-bitter upo fruit is generally safe for dogs in small amounts. The same cucurbitacin toxicity risk applies to pets — never feed bitter-tasting upo to animals. The vine itself is not listed as toxic by the ASPCA.

Common Pests & Diseases in the Philippines

• Fruit flies (Bactrocera cucurbitae): The cucurbit fruit fly — the most damaging pest of upo in the Philippines. Female flies puncture developing fruit to lay eggs; larvae feed inside, causing rot. Manage with cue-lure traps, fruit bagging, and prompt removal of fallen fruit.
• Downy mildew (Pseudoperonospora cubensis): Yellow angular leaf spots during humid weather. Severely affected leaves dry and die, reducing vine vigor and yield. Improve air circulation, avoid overhead watering, and apply copper-based fungicide preventively during the wet season.
• Powdery mildew (Podosphaera xanthii): White powdery coating on leaves, especially during cool, humid periods. Reduce leaf wetness and apply sulfur or potassium bicarbonate spray. Well-spaced, trellised vines with good airflow are less susceptible.
• Aphids: Colonize young shoots and leaf undersides, causing curling and stunting. Transmit viral diseases. Control with neem oil spray or strong water jets to dislodge.
• Leaf miners: Serpentine mining trails in leaves from fly larvae. Cosmetic damage is usually tolerable; severe infestations can be managed by removing and destroying mined leaves.
• Mosaic virus: Transmitted by aphids — causes mottled, distorted leaves and stunted growth. No cure — remove infected plants immediately to prevent spread. Control aphid populations to reduce virus transmission.

Frequently Asked Questions

Sources

• Plants of the World Online — Lagenaria siceraria (Molina) Standl. Royal Botanic Gardens, Kew.
• PROSEA (Plant Resources of South-East Asia) — Lagenaria siceraria species profile.
• USDA FoodData Central — Gourd, white-flowered (calabash), raw. FDC ID: 169228.
• FNRI-DOST — Philippine Food Composition Tables: Upo nutritional data.
• Erickson, D.L. et al. (2005). An Asian origin for a 10,000-year-old domesticated plant in the Americas. PNAS, 102(51), 18315-18320.
• Philippine Statistics Authority — Vegetable crop production statistics.

This guide is for informational purposes. Always taste upo before cooking — discard bitter fruit. Consult local agricultural extension offices (ATI, DA-RFO) for region-specific growing recommendations.