Some things to look for when buying annuals at a garden centre:
- balanced, compact and bushy growth, indicating that the plants have been given sufficient light;
- healthy-looking, firm, white roots that fill the soil mixture without completely covering the inner walls of the container and poking out the drainage holes;
- plants with flower buds but no open blooms are better able to withstand transplanting and form roots;
- insect-free (avoid any annuals with leaves covered in yellow spots, sticky substances or small black dots) and disease-free plants (avoid any plants covered with a downy white or grey substance).
Choose a cloudy day or wait until late in the day. Plants take better when the soil is loose, moist and relatively warm (minimum 7°C).
Keep your plants in a shady spot and water them as necessary if you are unable to plant them straight away.
Loosen the soil to a depth of 15 cm and add compost if you did not amend the soil in early spring (you may wish to add slow-release fertilizer).
Set the plants out on the ground exactly where you intend to plant them. Leave enough space between them to allow them to grow properly.
Dig a hole large enough to hold the roots. Remove the plant from its container without damaging the roots. When separating plants grown in flats, be careful to keep a root ball for each specimen.
Place the plant in the hole so that the crown is at ground level. Cosmos, zinnias and cleomes can be planted more deeply. Remove one or two leaves from the base of the stem and bury the bare part of the stem.
Sowing directly outdoors
Some annuals germinate and grow so fast that it is more advantageous to sow them directly in the flowerbed. Outdoor seedlings give good results if the seeds are sown in a loose, moist and relatively warm soil (minimum of 7°C). Some seeds need soaking for 24 hours in warm water before being planted. This is the case for the castor oil plant, morning glories, scarlet runner beans and sweet peas.
Loosen the soil to a depth of 15 cm and add compost if you did not amend the soil in early spring.
Decide where you want to plant and distribute seeds on the surface of the soil. You can also make a series of small furrows in which to plant the seeds. This last option will facilitate weeding when the seeds have germinated.
Cover seeds with soil and lightly tamp down to ensure contact. Some species, however, need light to germinate, so there is no need to cover them with soil.
Water gently so as not to dislodge the seeds. The soil must remain moist, not soggy, until germination. Seedlings emerging from the soil need water. Water regularly until they have multiple leaves.
Once the plants have several leaves, thin the seedlings to the recommended distance between each plant.