Pelham Gardens
Pelham GardensGrow What Matters

Onion

A kitchen essential. Grow from seed indoors or plant sets directly for a reliable midsummer harvest.

Establishing this month
First sprouts in 10–14 days

Sow

Jan – Apr

Plant Out

Mar – Apr

Harvest

Jul – Sep

Type

Both

Difficulty

Onion

Growing Calendar

Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Sow
Transplant
Harvest

This month: Apr

Move seedlings outside carefully

  • Harden off plants
  • Prepare soil outdoors
  • Space plants correctly
  • Water well after planting

Sowing Guide

What you'd find on the seed packet

Sow Depth

1cm

Spacing

10cm

Germination

10–14days

Thinning

Thin to 10cm apart when tops reach 5cm tall

Grower's Note

Growing from seed gives more variety choice. Sets are easier and more reliable for beginners.

Growing Stages

Approximate weeks from sowing to harvest

Sprouting

2wks

Seeds germinate and first leaves emerge. Keep warm and moist.

Establishing

8wks

Root system develops and plant builds structure. Pot on if needed.

Maturing

8wks

Plant reaches full size and begins producing. Harvest at peak.

Total~18 weeksfrom seed to harvest

Companion Plants

CarrotLettuceBeetrootChivesMarigold

Climate Control

Today

C

Humidity

%

Water

Every 3–4 days

Sunlight

6+ hours direct sun

Watch Out For

  • ! Onion fly lays eggs near the base — use enviromesh to exclude
  • ! Neck rot in storage — ensure bulbs are fully dry before storing
  • ! Bolting if sets are planted into cold, wet soil

What You'll Need

Equipment for growing onion

Modular Seed Tray

96-cell for precision sowing

Fine Rose Watering Can

Gentle shower for seedlings

Bamboo Canes

Pack of 20 × 120cm

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Grown Organically

Every method in this guide works with natural systems — no synthetic chemicals, no shortcuts.

Read our approach

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