Direct-Seeding
Annual Garden Flowers
Gardeners who plant a
large cutflower garden or like to edge their vegetable gardens with
annual flowers find it is more economical to direct-seed these
flowers into their garden than to purchase transplants. Many fast-growing
annuals will be flowering within 7 weeks of sowing the seed.
Unfortunately, there are a few disadvantages to direct-seeding. The
obvious problem is the plants will not be flowering as soon in the
garden as compared with those started indoors and set out as
transplants. Also, after the seedlings come up, they will need to be
thinned out to a uniform plant spacing.
The seed bed should
be worked well and raked so that the soil is fine, without large
clumps or clods. Direct-seed annual flowers after the threat of
frost is past in the spring and when the soil warms ups.
Some species
germinate faster if the seeds are given a special treatment prior to
planting. This treatment, called "scarification," breaks
the hard seed coat and allows the seeds to imbibe water more quickly,
resulting in earlier germination. Morning glories, for example, will
germinate faster and more uniformly if the seed coat is nicked
slightly. This can be done using a nail clipper to snip off a small
piece of the seed coat on one end. Scarify sweet pea seeds by filing
the seed coat on one side. After scarifying the seeds, soak them in
warm water for 24 hours before sowing.
Sow the seeds in
shallow furrows then cover them lightly with fine soil. Keep the
seed bed moist. After germination, thin the young seedlings to the
appropriate plant spacing. The excess seedlings can either be
discarded or transplanted to fill empty spaces in the row.
Annual garden
flowers that can be direct-seeded into the garden are listed below:
Annual garden
flowers that can be direct-seeded into the garden.
| Species |
Days to
germination |
Final plant
spacing |
Special
considerations |
| Bachelor's
button (Centaurea cyanus) |
7-14 |
6-12" |
bury seeds;
needs darkness for germination |
| Spider
flower (Cleome hasslerana) |
10-14 |
2-3' |
|
| Cosmos (Cosmos
bipinnatus and C. suphureus) |
5-10 |
10-24"
depending on variety |
|
| Annual
baby's breath (Gypsophilia elegans) |
10-15 |
18" |
|
| Sunflower (Helianthus
annuus) |
10-14 |
24" |
|
| Morning
glory (Ipomoea purpurea) |
5-7 |
4" |
|
| Sweet pea (Lathryrus
odoratus) |
10-14 |
4-6" |
scarify seeds; bury seeds; needs darkness for germination |
| Love-in-a-mist
(Nigella damascena) |
10-15 |
8" |
|
| Rose moss (Portulaca
grandiflora) |
10-15 |
12" |
|
| Creeping
zinnia (Sanvitalia procumbens) |
10-15 |
6" |
do not bury seeds; needs light for germination |
| Marigold (Tagetes
spp.) |
5-7 |
6-18"
depending on variety |
|
| Nasturtium (Tropaeolum
majus) |
7-12 |
8-12" |
scarify seeds; bury seeds; needs darkness for germination |
| Zinnia (Zinnia
elegans and Zinnia angustifolia) |
5-7 |
6-12" |
| 
