🍆 Sowing Aubergine Seeds: When to Move to the Greenhouse

Knowing when to move aubergine seedlings into the greenhouse is just as important as sowing them at the right time. Move them too early and cold nights can stall growth or cause damage. Move them too late and plants can become stressed or root-bound indoors.

This guide explains when aubergine seedlings are ready for the greenhouse, what conditions to wait for, and how to move them safely.

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• Aubergine Seeds

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• Seed Compost

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• Propagators

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• Seed Trays & Module Pots

Using seed trays or module pots keeps seedlings organised, improves drainage, and makes potting on easier with minimal root disturbance.

🌡️ Temperature Comes First

Aubergines are very sensitive to cold.

Only move seedlings into the greenhouse when:

• Night temperatures stay above 12–14°C
• Daytime temperatures are consistently mild
• There is no risk of frost

In most parts of the UK, this is usually late April to May, depending on weather and greenhouse protection.

🌱 How Big Should Aubergine Plants Be?

Seedlings should be:

• Well rooted but not pot-bound
• Growing steadily
• Showing several true leaves
• Sturdy, not leggy

Small, weak plants struggle to cope with cooler greenhouse conditions.

🏡 Heated vs Unheated Greenhouses

Heated greenhouse

• Plants can be moved earlier
• Temperatures remain stable day and night
• Late March or early April may be possible

Unheated greenhouse

• Wait until nights are reliably mild
• Late April to May is safest
• Extra protection may still be needed early on

Unheated greenhouses often feel warm during the day but drop sharply at night.

🌿 Hardening Off Before Moving

Even greenhouse moves should be gradual.

Before moving plants permanently:

• Place seedlings in the greenhouse during the day
• Bring them back indoors at night
• Do this for 5–7 days

This helps plants adjust without shock.

🌞 Positioning Plants in the Greenhouse

Once inside:

• Choose the warmest, brightest spot
• Avoid cold draughts near doors
• Keep plants off cold ground

Good positioning helps maintain steady growth.

🚫 Common Mistakes to Avoid

• Moving plants based on daytime warmth alone
• Ignoring night-time temperatures
• Putting small seedlings straight into cold soil
• Overwatering in cool greenhouse conditions

Most setbacks happen from moving plants too early.

🧠 Key Takeaway

Move aubergine seedlings into the greenhouse only when night temperatures are consistently above 12–14°C and plants are strong enough to cope. For most UK gardeners, late April to May is the safest window for unheated greenhouses.

Patience at this stage leads to healthier plants and better harvests later on.