Spinach vs Arugula for Hydroponic Growing (2026)
Arugula matures 10 days faster than spinach and tolerates the same cool water range, but spinach delivers nearly double the per-plant yield and requires higher EC - making arugula the faster crop and spinach the heavier producer.
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Spinach and arugula are both cool-water crops (15–21°C optimal) with overlapping pH ranges (6.0–7.0), making them natural system-mates. The key difference is speed vs yield: arugula finishes in 18–25 days at a low EC of 0.8–1.4, while spinach takes 28–40 days but produces 50–80 g/plant at a higher EC of 1.8–2.3 mS/cm.
Side-by-Side Comparison
| Feature | Spinach | Arugula | |---------|---------|---------| | Difficulty | Easy | Easy | | Days to First Harvest | 28–40 | 18–25 | | pH Range | 6.0–7.0 | 6.0–7.0 | | EC Range (mS/cm) | 1.8–2.3 | 0.8–1.4 | | Light (h/day) | 10–12 | 10–12 | | Water Temp (°C) | 15–20 | 15–21 | | Yield per Plant | 50–80 g | 30–50 g/tray | | Key Flavour Profile | Mild, iron-rich | Peppery, nutty |
Where Spinach Wins
- Higher yield: 50–80 g/plant vs arugula's 30–50 g/tray at equivalent spacing.
- Better nutritional density per gram (iron, folate, oxalate-bound calcium).
- Longer productive window before bolting under controlled light (10–12 h keeps it vegetative).
Where Arugula Wins
- Fastest leafy green in this pairing: harvestable at 18 days from transplant.
- Very low EC tolerance (0.8–1.4) means minimal nutrient spend per cycle.
- Peppery flavour is premium-priced at farmers' markets and in restaurants - better revenue-per-gram in many markets.
Growing Them Together
pH overlap is perfect (6.0–7.0), and both prefer the same short light window (10–12 h) and cool water. The EC gap is significant: arugula wants 0.8–1.4 while spinach thrives at 1.8–2.3. Running at a compromise of ~1.4–1.6 will keep arugula at the top of its range and spinach slightly under-fed - acceptable for baby spinach harvested early. For mature spinach, use separate reservoirs.
Which Should You Grow?
- Choose Arugula if you want the fastest harvest cycle, lowest EC spend, and a high-value peppery crop.
- Choose Spinach if yield per plant and nutritional density matter more, and you can sustain EC at 1.8–2.3.
- Grow both if you run a two-reservoir setup and want staggered quick (arugula) and medium (spinach) harvest cycles.