There are three main types of petunia seeds ; Multiflora and Floribunda types are ideal for bedding and have a good resistance to inclement weather. Grandiflora types, with their larger booms, are more suitable for containers. All three varieties produce some stunning flowers with a wide choice of colours and sizes.
This half hardy annual should be sown between February and April under glass in a gentle heat. This will mean that flowering will occur between June and September.
Petunia seeds should germinate within 10 to 21 days. When the seedlings are large enough to handle transplant them into trays 5cm apart. Petunia plants need to be acclimatised to outside condition before planting out (when all danger of frost has passed) at 30cm apart, in an open sunny position.