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How to Grow Arugula
Learn how to grow Arugula from seed to harvest in 30 days. Beginner difficulty. Complete nutrient guide, pH/EC requirements, and growing conditions for hydroponics, soil & greenhouse.
Backed by 12 peer-reviewed citations.
Temperature
Arugula is a cool-season leafy green. The previous database values were Fahrenheit values stored in Celsius fields; production should use Celsius targets. Cornell lists germination at 40-55F, while controlled germination studies found viable Eruca sativa seed can germinate across 5-40C with best stored-seed performance across a broad 15-35C band. For practical crop quality, keep production cool: Ohio State NFT arugula performed well at about 18.5C day and 16.8C night, and Cornell/Wisconsin extension guidance warns that heat drives bolting and stronger flavor. Use 18C as the controlled-environment setpoint, allow roughly 10-25C for growth, and avoid sustained warm conditions above 25C when leaf quality is the goal.
Humidity
A 50-75% relative humidity range is supported by controlled-environment arugula studies. Ohio State's NFT experiment logged about 50.9% RH with strong growth at optimal EC, while a fully controlled Eruca vesicaria chamber study used 70 +/- 5% RH without visual leaf damage.
Light
Arugula tolerates moderate to high controlled-environment light. Ohio State produced hydroponic arugula at a DLI of about 17 mol/m2/d under a 16-hour photoperiod, which corresponds to roughly 300 umol/m2/s average PPFD.
Airflow
No arugula-specific airflow velocity trial was found, so airflow is verified from controlled-environment leafy-green practice and disease biology rather than a species-specific dose response. Cornell CEA recommends vertical airflow in DWC leafy greens to prevent tip burn under DLI 17 by improving calcium transport,…
Nutrition
Hydroponic arugula nutrition should be moderate, not aggressively high. Ohio State found the best combined yield and quality at EC 1.5-1.8 dS/m, with total nitrogen around 110-150 mg/L; EC 1.2 caused deficiency symptoms, while EC 2.1 increased chlorosis and nitrate risk.
Propagation
Arugula is propagated by seed and is easy to start. Cornell recommends direct sowing as soon as soil can be worked, with seed planted about 1/4 inch deep and initially 1 inch apart, then thinned to about 6 inches for individual plants or left denser for baby-leaf harvest.
Harvesting
Arugula is harvested young for best flavor. Wisconsin extension states leaves can be harvested once a few inches long, either by removing outer leaves or cutting the whole plant 1-2 inches above the ground for regrowth in as little as 3-4 weeks.
Calendar
For outdoor temperate gardens, arugula is a spring and fall crop. Direct sow as soon as soil can be worked in spring, continue sowing every 2-3 weeks, and resume sowing in late summer for fall harvest.
Environments
Arugula is suitable indoors, outdoors, in greenhouses, and in containers. Outdoors, it is a cool-season crop for spring and fall and can tolerate cold better than heat.
System Compatibility
Arugula is highly compatible with hydroponics. NFT is directly verified by Ohio State's four-EC arugula trial, which used recirculating channels, 20 cm plant spacing, daily EC adjustment, and pH near 5.82.
Growing Media
Rockwool is the best-verified hydroponic medium for arugula seedlings: Ohio State used Horticubes for NFT propagation, and the Arkansas hydroponic study sowed arugula into 162-cell rockwool sheets before transfer to DWC vessels. Cornell baby-leaf DWC also supports foam trays filled with peat-perlite or coir substrate.
Container Specs
Arugula has modest container needs because it is compact and fast. A 15 cm deep tray is enough for baby-leaf production, while 20 cm or deeper containers better support repeated cut-and-come-again harvests.
Training & Support
Arugula needs no training or structural support. It grows as a low leafy rosette for harvest, and the useful interventions are thinning, succession sowing, and repeated cutting before flowering.
Common Issues
The most important arugula issues are bolting, flea beetles, downy mildew, tip burn, root rot, nitrate accumulation, chlorosis from pH drift, and contaminant insects. Cornell and Wisconsin both identify flea beetles as the key garden pest, and an open-access Journal of Economic Entomology study found Eruca sativa was…