Spinach in a hydroponic system
Common and Alternative Names
- Spinach (Spinacia oleracea)
- English Spinach
- Smooth-Leaf Spinach
- Baby Spinach (young harvest)
- New Zealand Spinach (Tetragonia tetragonioides) - unrelated but similar use
Varieties
- Bloomsdale Long-Standing: 'Bloomsdale' (Spinacia oleracea 'Bloomsdale Long-Standing')
- Space: 'Space' (Spinacia oleracea 'Space')
- Butterflay: 'Butterflay' (Spinacia oleracea 'Butterflay')
- Olympia: 'Olympia' (Spinacia oleracea 'Olympia')
- Giant Winter: 'Giant Winter' (Spinacia oleracea 'Giant Winter')
- Merlo Nero (Italian heirloom)
Positive Identification
- Oblong to triangular, smooth leaves (young) or lightly crinkled (mature)
- Leaves on long, slender petioles arising from a basal rosette
- Bright to dark green coloration, sometimes with a slight waxy sheen
- Stems and veins slightly succulent, tender to the touch
- Small, inconspicuous greenish flowers on terminal spikes when bolting
Toxic Look-Alikes
- New Zealand Spinach (Tetragonia tetragonioides) - edible but not true spinach
- Waterleaf (Hydrophyllum spp.) - similar leaf shape, edible but different family
- Wild Parsnip (Pastinaca sativa) - toxic sap, different flower umbel
- Hemlock (Conium maculatum) - toxic, umbrella-shaped flower clusters
Common Plant Parts and Uses
Part |
Uses |
Leaves |
Fresh salads, cooking, smoothies; high in vitamins & minerals |
Stems |
Blanched in soups or stews; often discarded if fibrous |
Flowers |
Rare in harvest stage; attract pollinators if allowed to bolt |
Roots |
Not typically consumed; anchorage in hydroponic media |
Growing Parameters
Field |
Range |
Optimal |
Electrical Conductivity (EC) |
1.2 - 2.0 mS/cm |
1.6 mS/cm |
pH |
5.5 - 6.5 |
6.0 |
Total Dissolved Solids (TDS) |
600 - 1,200 ppm |
800 ppm |
Temperature |
16 - 20 °C (61-68 °F) |
18 °C (64 °F) |
Hours of Light |
12 - 16 h/day |
14 h/day |
Seasons to Plant |
Early Spring, Late Summer |
Early Spring |
Seasons to Harvest |
Spring, Fall |
Spring |
Wattage of Grow Lights |
20 - 30 W/ft2 |
25 W/ft2 |
Propagation Methods
- Seed-direct sow in rockwool cubes, coco coir plugs, or germination trays
- Cuttings-rare; typically grown from seed
Compatibility with Hydroponic Systems
System Type |
Compatibility |
Notes |
Deep Water Culture (DWC) |
Excellent |
Shallow roots thrive in oxygenated reservoir |
Recirculating DWC (RDWC) |
Excellent |
Uniform nutrient delivery; supports multiple heads |
Nutrient Film Technique (NFT) |
Excellent |
Thin film provides continuous flow past roots |
Ebb and Flow |
Good |
Periodic flooding prevents waterlogging |
Drip Irrigation |
Good |
Precise moisture control at root zone |
Kratky Method |
Good |
No pumps needed; monitor nutrient depletion |
Wick System |
Fair |
Wicks must deliver sufficient moisture; best for small heads |
Aeroponics |
Excellent |
Fine mist encourages rapid growth |
Common Pests
- Aphids (Aphidoidea)
- Leaf Miners (Liriomyza spp.)
- Whiteflies (Trialeurodes vaporariorum)
- Fungus Gnats (Bradysia spp.)
- Downy Mildew (Peronospora farinosa)
- Spider Mites (Tetranychus urticae)
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