How to Grow Onions in the Philippines

Why Grow Onions at Home?

Growing onions at home in the Philippines saves you money on one of the most essential kitchen ingredients. Onion prices in the Philippines have been notoriously volatile, sometimes reaching over 600 pesos per kilo during supply shortages. Growing your own sibuyas ensures a steady supply and puts you in control of quality.

Onions (Allium cepa) are a staple in Filipino cooking. You use them in practically every dish from sinigang and adobo to ginisa and tortang talong. The Philippines grows several varieties including Red Creole, Yellow Granex, and the popular native red onion from Nueva Ecija.

Home gardeners can grow bulb onions in raised beds and garden plots or spring onions in containers and small pots. This guide walks you through the entire process from planting to harvest so you can enjoy fresh, homegrown sibuyas all year round.

What You Need to Grow Onions

• Onion seeds or sets - Seeds take longer but offer more variety choices. Sets (small bulbs) are faster and easier for beginners.
• Well-draining raised bed or containers - At least 15 cm deep for bulb onions and 10 cm for spring onions.
• Sandy loam soil - Mix loam soil with river sand and aged compost. Onions dislike heavy, waterlogged soil.
• Full sun location - Onions need at least 6 hours of direct sunlight for proper bulb development.
• Complete fertiliser - 14-14-14 at planting time and potassium-rich fertiliser during bulb formation.
• Mulch material - Rice straw or dried grass clippings to control weeds and retain moisture.

Step-by-Step Guide to Growing Onions

Step 1: Choose Your Planting Method

You can grow onions from seeds, sets (small bulbs), or the bottom of store-bought onions. Seeds offer the widest variety selection but take 90 to 120 days. Sets give you a 30-day head start and are easier to handle. For spring onions, simply plant the root end of store-bought ones in moist soil.

Step 2: Prepare the Soil

Onions need loose, well-draining soil rich in organic matter. Mix 50% loam soil, 30% compost, and 20% river sand. For raised beds, build the bed at least 15 cm high. Remove all weeds and debris. Work the soil until it is fine and crumbly. A pH of 6.0 to 7.0 is ideal for onion production.

Step 3: Start Seeds in a Nursery Bed

If using seeds, sow them in a nursery bed or seedling tray first. Scatter seeds thinly and cover with 1 cm of fine soil. Water with a fine spray twice daily. Seedlings are ready for transplanting 30 to 45 days after sowing when they reach pencil thickness. Harden off seedlings by reducing water for 3 days before transplanting.

Step 4: Transplant or Plant Sets

Transplant seedlings or plant onion sets 10 to 15 cm apart in rows spaced 20 cm apart. Plant so that the top of the bulb sits just at or slightly below the soil surface. Firm the soil around each plant and water immediately. For container growing, use one bulb per 15 cm pot or space them 10 cm apart in long planters.

Step 5: Water Consistently

Water onions every 2 to 3 days during the dry season. The soil should stay moist but never waterlogged. Overwatering causes bulb rot, the most common reason for failure. Reduce watering as bulbs mature and stop completely 2 weeks before harvest to allow the outer skins to dry and toughen.

Step 6: Fertilise at Key Stages

Apply complete fertiliser (14-14-14) at planting and again 30 days later. When bulbs start swelling, switch to a potassium-rich fertiliser like muriate of potash (0-0-60) to promote bulb size and storage quality. Side dress fertiliser 5 cm from the plants and water in immediately.

Step 7: Control Weeds and Pests

Keep the onion bed weed-free. Weeds compete aggressively with the shallow onion roots for water and nutrients. Mulch between rows with rice straw to suppress weeds. Check for thrips (tiny insects on leaves) and spray with neem oil. Remove any plants showing signs of purple blotch disease.

Onion Care Tips for Philippine Climate

Sunlight

Onions are day-length sensitive plants. Philippine varieties are short-day types that form bulbs when they receive 10 to 12 hours of light. Ensure plants get full sun for at least 6 hours daily. Shaded onions produce lush green tops but small or no bulbs.

Watering During the Rainy Season

Growing onions during the rainy season is challenging because they are prone to fungal diseases in wet conditions. If you must grow them during this period, use raised beds at least 20 cm high with excellent drainage. Cover beds with clear plastic during heavy downpours to prevent waterlogging.

Temperature

Onions grow best between 20 and 30 degrees Celsius. Philippine lowland temperatures suit onion production during the cooler months from November to February. Highland areas like Benguet and Bukidnon offer year-round conditions for onion growing.

Common Problems When Growing Onions

Small or No Bulbs

Small bulbs result from overcrowding, insufficient sunlight, or planting the wrong variety for your day length. Space plants at least 10 cm apart. Ensure 6 hours of direct sun daily. Use short-day onion varieties suited to tropical latitudes.

Bulb Rot

Rot develops in waterlogged soil or during extended rainy periods. Improve drainage by adding river sand to the soil mix. Raise beds above ground level. Stop watering 2 weeks before harvest. Remove and discard any bulbs showing soft, smelly brown spots.

Purple Blotch Disease

This fungal disease causes purple-brown lesions on leaves during humid weather. Remove infected leaves immediately. Apply copper-based fungicide as a preventive spray every 7 to 10 days during the wet season. Improve air circulation between plants.

Thrips Damage

Thrips are tiny insects that rasp the leaf surface, causing silvery streaks and curled leaves. Spray neem oil solution weekly during dry weather when thrips populations peak. Yellow sticky traps near the bed help monitor and reduce populations.

When to Harvest Onions

Onions are ready to harvest 90 to 120 days after planting. Watch for these signs of maturity.

• The tops fall over naturally and turn yellow or brown.
• The neck of the bulb feels soft and thin when squeezed.
• The outer papery skin is dry and crinkly.
• At least 50% of the plants in the bed have fallen tops.

Pull bulbs gently from the soil on a dry, sunny day. Leave them on the soil surface to cure in the sun for 2 to 3 days. Then move them to a shaded, well-ventilated area for another 2 weeks of curing. Properly cured onions store for 2 to 3 months in a cool, dry location.

For more detailed species information, visit our sibuyas (onion) plant guide page.

Frequently Asked Questions