Petunia: Sowing, planting and harvest calendar
How to sow petunias successfully under cover?
Plan your indoor petunia sowing about ten weeks before outdoor planting, adjusting the date to the end of frost risk in your area. Use clean seed trays or small pots with drainage holes and a fine seed-starting medium. Moisten the growing medium before distributing the seeds across its surface.
The seeds are tiny and need light to germinate. Place them on the surface and press gently to ensure contact, without burying them or covering them with compost. For pelleted seeds, also follow the packet instructions. Water very gently so you do not move the seeds or wash them into clumps.
Keep the container in bright light and warmth, around 24 to 27 °C during germination. A clear cover helps maintain moisture, but keep the covered container away from direct sunshine to prevent overheating. Remove the cover as seedlings emerge and provide enough light in a cooler place that remains frost-free.
Move seedlings into individual pots when they have several true leaves, preserving their roots and holding them by a leaf rather than the stem. Continue growing without saturating the medium. Before final outdoor planting, gradually acclimatise the plants to wind and sun. Plant outside only after frost risk has passed, allowing spacing appropriate to the cultivar.
How to sow petunias successfully outdoors?
How do you plant petunias?
When does the petunia flower?
How to care for this plant
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Remove faded flowers
If your petunia retains faded flowers, remove them with their short stalks without harming nearby buds. Self-cleaning varieties do not need this.
