Spinach
Spinacia oleracea
Spinach is a fast-growing cool-season crop that bolts readily in heat or long days. It is best sown in spring and autumn, avoiding the height of summer. Leaves are ready quickly and can be harvested as baby leaf or left to mature. Succession sowing every 3 weeks provides continuous supply.
Terminology
Key facts
- Family
- Amaranthaceae
- Category
- Leafy
- Height
- 20-30 cm
- Soil type
- Fertile, moisture-retentive, well-drained
- Soil pH
- 6.5-7.5
- Sowing window
- Feb–Apr, Aug–SepNow
- Sowing depth
- 20 mm
- Spacing
- 15 cm between plants, 30 cm between rows
- Watering
- medium
- Frost sensitivity
- low
- Days to maturity
- 40-60 days from sowing
- Harvest window
- Apr - Nov
- Storage
- Refrigerator
- Storage duration
- 2-3 days; wilts quickly after harvest
Soil
Preparation
- -Incorporate well-rotted compost before sowing
- -Avoid acid soils - spinach is sensitive to low pH
Sowing notes
- -Avoid sowing June-July - long days and heat trigger bolting
- -Earliest spring sowings (February-March) benefit from cloche protection
- -Autumn sowings under cover extend the season into winter
- -Succession sow every 3 weeks for continuous supply
- -Sow thinly - overcrowding increases disease pressure
Harvest notes
- -Harvest outer leaves first or cut the whole plant above the growing point
- -Baby leaf can be harvested from 25-30 days
- -Pick promptly once plants begin to bolt - leaves become bitter quickly
Varieties
Issues & threats
Wilting
EnvironmentalPlants are drooping or losing vigour. Most commonly caused by water stress but can also indicate root damage, vascular disease, or heat scorch. Identifying the cause quickly is important as some causes are serious.
Poor germination
EnvironmentalSeeds are emerging unevenly or not at all. Usually caused by soil temperature being too low, seeds sown too deep, poor seed-to-soil contact, or old seed stock.
Damping off
Fungal diseasePythium spp. / Phytophthora spp.
Young seedlings collapse at or just below soil level, caused by fungal pathogens that thrive in overwatered, poorly ventilated growing conditions. Can spread rapidly through a seed tray.
Yellowing leaves
EnvironmentalLeaves are turning yellow, which can indicate a range of problems including nutrient deficiency, overwatering, disease, or natural senescence. Identifying whether the pattern is upper or lower leaves, whole leaves or between veins, is key to diagnosis.
Stunted growth
EnvironmentalPlants are significantly smaller or slower to develop than expected. May be caused by poor soil, nutrient deficiency, root restriction, compaction, pest damage to roots, or disease.
Chewing damage
PestGeneral chewing damage from an unidentified pest, leaving holes or missing leaf sections. May be caused by caterpillars, beetles, or other insects. Inspect at dusk to identify the culprit.
Sap-sucking pests
PestGeneral sap-feeding pest activity causing weakened or distorted growth. May be caused by aphids, whitefly, scale insects, or other sucking insects. Inspect leaf undersides and growing tips to identify the pest.