There are three main types of garden flowers: annual plants, biennial plants, and perennial plants.

Plants: Annuals

Plants of this description arrive at maturity, bloom, produce seed, and die in one season. There are three different types of annual flowers .....

Hardy Annuals

The seed of hardy annual garden flowers can be sown thinly outdoors during March, April, or May in fine soil, covering them slightly — very small seeds need just a light covering of compost over them. When the plants are large enough to handle, thin them out to let them to develop fully. In this way strong and sturdy plants are produced and their flowering properties enhanced ..... continued below

Garden Plants for Sale on

Many hardy annuals can be sown in August and September for spring flowering, and require little or no protection from frost.

Half-Hardy Annuals

Half hardy annuals are best sown in seed trays 2 or 3 in. deep during February and March, and placed in a greenhouse at a temperature of about 60 degrees. The seed tray should be nearly filled with equal parts of potting compost and coarse silver sand, thoroughly mixed, and have holes at the bottom for drainage. Scatter the seeds thinly and evenly over the soil and cover very lightly.

Very small seeds, such as lobelia and musk, should not be covered by compost but a sheet of glass over the box helps as it keeps the moisture from evaporating too quickly. If watering become necessary, care must be taken that the seeds are not washed out.

As soon as the young plants appear, remove the glass and place them near the light, where gentle ventilation can be given them to prevent long and straggly growth. Harden off gradually, but do not plant out until the weather is favourable. Seed can also be sown in a cold frame in April, or in the open border during May; or the plants can be raised in the windows of the sitting-room.

Tender Annuals

These must be sown in a rather stronger heat than is necessary for half-hardy varieties. As soon as they are large enough to be moved, prick them off into small pots, gradually potting them on into larger sizes until the flowering size is reached.

Text derived from: Gardening for the Millions by Alfred Pink