Arugula (Eruca vesicaria)

About Arugula

Arugula (Eruca vesicaria, syn. Eruca sativa) is the peppery Mediterranean salad green that has become one of the defining ingredients of modern restaurant cuisine worldwide — and in the Philippines, it represents the cutting edge of the country's evolving relationship with raw, salad-based eating. Once available only in high-end Manila restaurants importing European baby greens, arugula is now increasingly grown by Filipino urban gardeners on balconies, rooftops, and in small hydroponic setups, part of a broader trend toward growing specialty salad greens at home.

The plant belongs to the Brassicaceae family — the same mustard clan as pechay, mustasa, labanos, and kangkong-dagat. Like its Brassicaceae relatives, arugula contains glucosinolates — the sulfur compounds that produce its characteristic peppery, mustard-like bite. Young baby arugula (20-25 days) has a mild, nutty flavor with a gentle peppery finish; mature leaves (35+ days) or heat-stressed plants develop an intensity that can rival wasabi, making harvest timing critical for palatability.

Arugula is exceptionally fast-growing — seeds germinate in 3-5 days and the first baby leaves are harvestable in just 20-25 days. This speed makes it one of the quickest-to-harvest salad crops available, but the same metabolic urgency drives rapid bolting in Philippine heat. Managing this race between harvest readiness and bolting is the central challenge of tropical arugula growing, and the reason succession planting (sowing new batches every 2-3 weeks) is essential rather than optional.

For Filipino growers, arugula occupies an interesting cultural niche: it is a "premium" salad green associated with Italian, Mediterranean, and modern Western cuisine, but it grows with the same ease and speed as its Filipino Brassicaceae cousins pechay and mustasa. The barrier is not difficulty — arugula is simpler to grow than many traditional Filipino vegetables — but awareness. Any grower who can produce pechay can produce arugula, using the same cool-season timing and shade management strategies.

History & Discovery

Eruca vesicaria is native to the Mediterranean region — southern Europe, North Africa, and western Asia. It has been cultivated since at least Roman times, when it was considered both a food and a medicinal plant. The Romans ate arugula in salads and believed it had aphrodisiac properties — a reputation that persisted through the Middle Ages. The name "arugula" is Italian (from Latin "eruca"); "rocket" is the English name (from French "roquette," also from Latin "eruca").

The genus Eruca contains only a few species, with E. vesicaria being the sole widely cultivated member. The specific epithet vesicaria means "bladder-like," referring to the inflated seed pods. In modern taxonomy, the cultivated form is sometimes treated as Eruca vesicaria subsp. sativa, with sativa meaning "cultivated." Wild arugula (Diplotaxis tenuifolia) is a different genus — it has narrower leaves, a more intense flavor, and is perennial rather than annual.

Arugula arrived in the Philippines relatively recently — primarily through the influence of Italian restaurants, international hotel kitchens, and the global food media that made arugula a symbol of contemporary salad culture in the 2000s-2010s. Unlike most Filipino vegetables, which arrived through ancient trade routes or colonial-era introduction, arugula's Philippine story is one of modern culinary globalization — driven by chefs, food bloggers, and health-conscious consumers seeking diversity beyond traditional cooked greens.

How to Plant Arugula in the Philippines

Arugula is always direct-sown — it resents transplanting because its taproot is easily damaged. Seeds are increasingly available at Philippine garden centers, online seed shops, and specialty agricultural suppliers. The plant requires minimal space and grows well in shallow containers, making it ideal for balcony and windowsill growing.

Propagation Steps

1. Direct sow seeds: Scatter seeds thinly on moist soil surface, then cover with 3-5 mm of fine soil. Press gently. Water with a fine spray. Space rows 15-20 cm apart. For containers, use shallow pots (15+ cm deep, any width). Seeds germinate in 3-5 days — one of the fastest germinating vegetables.
2. Thin seedlings at 7-10 days: When seedlings are 5 cm tall, thin to 10-15 cm apart. Eat the thinnings — baby arugula thinnings are the mildest, most tender leaves the plant produces and are restaurant-quality microgreens.
3. Position in partial shade: Full Philippine sun causes immediate bolting and fierce bitterness. Morning sun (3-4 hours) with afternoon shade is ideal. Shade cloth (50-70%), east-facing balconies, or positions under taller plants provide the protection needed. Highland growers can use more sun.
4. Water daily: Keep soil evenly moist. Arugula wilts and bolts quickly under drought stress. Shallow roots mean frequent light watering rather than deep soaking. Mulch lightly to conserve moisture.
5. Succession plant: Sow new batches every 2-3 weeks throughout the cool season (November-February). Arugula's productive window in Philippine heat is short — succession planting ensures continuous harvest rather than a single boom-bust cycle.
6. Harvest young: Begin cutting outer leaves at 20-25 days when 8-15 cm long. Cut 3 cm above the base for regrowth. Harvest 2-3 times per planting before bolting. Morning harvest produces the crispest, mildest leaves.

Best Planting Season

In lowland Philippines (Metro Manila): the cool dry season from November to February only. The amihan months offer the narrow temperature window (22-28°C) where arugula can produce quality leaves before bolting. Year-round growing is possible only with significant shade management and hydroponic climate control. In highland areas: arugula grows year-round with excellent quality.

Care Guide

Sunlight

Partial shade is essential in the Philippine lowlands — 3-4 hours of morning sun with afternoon shade. Full direct sun above 28°C triggers bolting within days. East-facing exposures are ideal. Shade cloth (50-70%) extends the growing season. In highland areas, full sun to partial shade works well year-round. Arugula tolerates less light than lettuce before quality declines.

Water

Daily watering with a fine spray — arugula has shallow roots that dry out rapidly in Philippine heat. Consistent moisture is critical: drought stress concentrates glucosinolates, making leaves unpleasantly bitter and triggering bolting. Keep soil evenly moist but not waterlogged. Morning watering reduces disease risk. Mulch conserves moisture between waterings.

Soil

Well-draining, fertile potting mix or sandy loam amended with compost. pH range of 6.0-7.0. Arugula is not fussy about soil — it grows in a wide range of conditions as long as drainage is adequate. Container growing in standard potting mix works well. Rich soil produces milder, more tender leaves; poor soil increases peppery intensity.

Humidity & Temperature

Optimal temperature: 15-22°C — genuinely cool-season. Temperatures above 25°C increase bitterness; above 28°C, bolting is almost inevitable. Philippine lowland temperatures are challenging — the amihan months offer the best window. Moderate humidity (50-70%) is ideal; high tropical humidity (80%+) increases downy mildew risk. Good air circulation helps manage humidity.

Fertilizer

Light feeding is sufficient — arugula's short growing cycle (25-35 days) means a single application of balanced fertilizer at sowing time is often enough. Avoid heavy nitrogen in hot conditions — it promotes rapid, lush growth that bolts even faster. Liquid seaweed or fish emulsion at half strength every 2 weeks supports steady growth. For hydroponics, use standard leafy-green nutrient solution at EC 0.8-1.2.

Bolting Management

Bolting is inevitable — the question is when, not if. In Philippine lowland heat, the productive window between harvestable size and bolting can be as short as 10-15 days. Maximize this window: grow in coolest season, provide shade, maintain moisture, harvest young, and succession plant. Once the central flower stalk appears, harvest all remaining leaves immediately — they become very bitter within days. The flowers themselves are edible and attractive.

Growing Medium Options

Edible Uses & Nutrition

Arugula is eaten primarily raw — its peppery, nutty flavor is best appreciated fresh, and cooking diminishes the characteristic bite. The leaves wilt quickly after harvest and do not store well — one of the strongest arguments for growing it at home rather than buying it, since freshly picked arugula is dramatically superior to supermarket arugula that may be days old.

Edible Parts

• Leaves (primary): Raw in salads, as garnish, or wilted briefly in warm dishes
• Flowers: Edible with concentrated peppery-sweet flavor — excellent salad garnish
• Young seed pods: Crunchy, spicy — like a mild wasabi
• Seeds: Can be pressed for oil (taramira oil) or ground as a spice — rarely done in the Philippines

Culinary Uses

• Fresh salads: The classic use — arugula with cherry tomatoes, shaved parmesan, and balsamic vinaigrette (Italian-style); or mixed with other greens for a peppery accent
• Pizza topping: Fresh arugula scattered on pizza after baking — the heat slightly wilts the leaves while preserving their flavor
• Pasta garnish: Tossed into warm pasta just before serving — the residual heat wilts the arugula gently
• Sandwiches and burgers: A handful of arugula adds peppery crunch to any sandwich
• Arugula pesto: Blended with olive oil, garlic, pine nuts or cashews, and parmesan — a more peppery alternative to basil pesto
• Smoothies: Mild baby arugula blended into green smoothies — adds nutrition without overwhelming flavor
• Steak or grilled meat accompaniment: A bed of arugula under grilled meat — the peppery flavor cuts through richness

Nutritional Information

Per 100 g of raw arugula (USDA FoodData Central):

Arugula is a nutritional standout among salad greens — excellent vitamin K (109% DV), good vitamin A (47% DV), and notably high calcium (16% DV, one of the best plant sources). The glucosinolates are bioactive phytochemicals studied for anti-inflammatory properties. Arugula's high calcium-to-calorie ratio makes it valuable as a non-dairy calcium source. The protein content (2.6 g) is higher than most salad greens.

Air Quality & Oxygen

As a small, fast-cycling annual, arugula provides minimal individual air quality benefits. Its environmental value lies in converting small, underused urban spaces — windowsills, shallow containers, balcony corners — into micro-productive areas that collectively contribute to urban greening. A window box of arugula replaces a bare surface with a few square centimeters of photosynthetically active leaf area, producing oxygen and capturing dust for 4-6 weeks before the cycle restarts.

The growing trend of home salad-green production (arugula, lettuce, kale, microgreens) contributes to a broader shift in urban food systems — reducing food miles, packaging waste, and the carbon footprint of perishable produce transportation from highland farms to Metro Manila consumers.

Toxicity & Safety

Humans: Arugula is completely non-toxic and safe for all ages. The glucosinolates that produce the peppery flavor are not toxic at food quantities — they are actually studied for health-promoting properties. People with thyroid conditions should note that Brassicaceae vegetables contain goitrogens that may interfere with iodine uptake in very large raw quantities — cooking reduces goitrogens, but arugula is typically eaten raw and in small salad portions, so the risk is minimal. People on blood thinners should maintain consistent arugula intake due to its high vitamin K content.

Pets: Arugula is not listed as toxic to dogs or cats by the ASPCA. Small amounts of plain, washed arugula are safe for dogs. The peppery flavor naturally limits consumption — most dogs dislike the taste. Not a concerning plant for pet households.

Common Pests & Diseases in the Philippines

• Flea beetles: Tiny jumping beetles that create shot-hole damage in leaves — the most common pest of arugula and all Brassicaceae crops. Worst on seedlings. Control with neem oil, kaolin clay spray, or floating row covers. Mature plants tolerate moderate damage.
• Aphids: Green or black colonies on undersides of leaves. Stunt growth and cause curling. Control with strong water spray, neem oil, or insecticidal soap. Check daily — populations explode rapidly on young, tender growth.
• Diamond-back moth (Plutella xylostella): Small caterpillars that skeletonize leaves — the same pest affecting pechay and mustasa. Control with Bt spray. The short growing cycle of arugula means damage has limited time to accumulate.
• Downy mildew: Yellow patches on upper leaf surface with gray fuzz underneath — common during cool, humid periods. Improve air circulation, avoid overhead watering, and space plants properly. Remove infected leaves immediately.
• Slugs and snails: Feed on tender leaves at night. Worst during wet season. Beer traps, crushed eggshell barriers, or iron phosphate bait. Elevated containers avoid slug contact.
• White rust (Albugo candida): White pustules on undersides of leaves — a fungal disease specific to Brassicaceae. Remove infected leaves. Improve air circulation. Avoid planting where other Brassicaceae crops had the disease.

Frequently Asked Questions

Sources

• Plants of the World Online — Eruca vesicaria (L.) Cav. Royal Botanic Gardens, Kew.
• USDA FoodData Central — Arugula, raw. FDC ID: 169387.
• FNRI-DOST — Philippine Food Composition Tables: Leafy greens nutritional data.
• Martinez-Sanchez, A. et al. (2008). Glucosinolates and isothiocyanates in health and disease. Trends in Molecular Medicine, 14(5).
• Bell, L. & Wagstaff, C. (2014). Glucosinolates, myrosinase hydrolysis products, and flavonols found in rocket (Eruca sativa). Journal of Agricultural and Food Chemistry, 62(20).

This guide is for informational purposes. Consult local agricultural extension offices (ATI, DA-RFO) for region-specific growing recommendations.