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How to Grow Marrow

Cucurbita pepo

Tender Warm Season Continuous Harvest

When to Start

Start seeds indoors 4 weeks before your last frost date. Transplant outdoors once night temperatures stay above 10°C and soil has warmed to at least 12°C.

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Growth Stages

Sow seeds
Germination ~7d
Flowering ~60d
Fruiting ~65d
Harvest ~75d

Approximate days from start

Care Essentials

  • Once flowering begins, feed every two weeks with a high-potash liquid fertiliser. Before planting, enrich the soil generously with well-rotted compost or manure — marrows are hungry plants.
  • Marrows need full sun, rich soil, and consistent moisture. Water deeply at the base each week and mulch well to retain moisture. In cool summers, hand-pollinate flowers to improve fruit set.

Companion Planting

Growing Conditions

Min. soil temperature: 12°C+
Germination temperature: 20–28°C

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Spacing & Planting

Plant spacing 75 cm
Row spacing 85 cm
Sow depth 2.5 cm
Mature height 40 cm
Mature spread 120 cm

Marrows are trailing plants that need plenty of room. Train along the ground or over a compost heap. Allow at least 1 square metre per plant.

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Care Guide

Feeding
Once flowering begins, feed every two weeks with a high-potash liquid fertiliser. Before planting, enrich the soil generously with well-rotted compost or manure — marrows are hungry plants.
Watch for
  • Powdery mildew (white coating on leaves, common late season)
  • Grey mould / Botrytis on fruit and stems
  • Slugs and snails on young plants
  • Aphids on new growth

Pests & Diseases

Pest Slugs and Snails

Identification: Holes in leaves and stems, particularly damaging to young plants

Organic treatment:
  • Physical barriers around young plants
  • Beer traps
  • Hand picking at dusk
Chemical treatment:
  • Slug pellets - use sparingly
Pest Aphids

Identification: Small insects clustering on undersides of leaves and new growth

Organic treatment:
  • Insecticidal soap
  • Strong water spray
  • Encourage natural predators
Chemical treatment:
  • Approved systemic insecticides
Disease Powdery Mildew

Symptoms: White powdery coating on leaves, more common late in season

Treatment: Remove affected leaves, improve ventilation

Prevention: Good air circulation, water at soil level, avoid overcrowding

Disease Grey Mould (Botrytis) Botrytis cinerea

Symptoms: Fuzzy grey mould on fruits and stems

Treatment: Remove affected parts, improve growing conditions

Prevention: Good air circulation, remove damaged fruits promptly

Growing Conditions

Min. soil temperature12°C
Germination temperature20–28°C
Base growth temperature10°C
Min. daylength to start10h
Photoperiod sensitivityday neutral

Frequently Asked Questions

How far apart should I plant Marrow?
Plant Marrow 75cm apart with 85cm between rows.
When can I harvest Marrow?
Marrow is ready to harvest approximately 45 days after transplanting.
Is Marrow frost hardy?
Marrow is classified as Tender.

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