Sowing your seeds: important factors for germination
WHEN sowing seeds in your garden, keep these three important factors for germination in mind.
1/ SOWING DEPTH
- Depends on the size of the seed.
- Fine seed should be barely covered.
- Medium-sized seed may be planted to a depth of about 6mm.
- Larger seeds are planted more deeply.
Seeds that need light
- Some tiny seeds need to be contacted by light for germination to occur. Examples are begonias, impatiens, petunias, primulas and coleus.
- Press these into the surface of moist seed raising mix.
- Cover with plastic wrap or glass.
- Keep in bright shade.
- Water by misting with fine spray or immersing the base of the container in a tray of water.
- Varieties: ageratum, alyssum, antirrhinum, aquilegia, begonia, campanula, impatiens, petunia, primula, salvia, stock, lettuce.
Seeds that need dark
- Some seeds need to be totally protected from light. Examples are violas, pansies and nasturtiums.
- Cover with a sheet of newspaper or cardboard. Remove after germination.
- Varieties: calendula, cornflower, delphinium, forget-me-not, gazania, pansy, schizanthus, sweet pea, verbena, viola, coriander.
2/ SOIL MOISTURE
Seeds have differing moisture requirements.
- Some very fine seeds, (eg. some petunias) have been 'pelletised', coated with a layer of inert material to make them easier to handle. These should be watered more frequently than uncoated seeds.
- Avoid watering while the soil remains moist or until the seedlings emerge. Do not pre-soak these seeds.
- Keep soil or seed raising mix moist for slower germinating seeds (such as pansies which may take 21-28 days).
- After seedlings have emerged, water thoroughly but less frequently to encourage the development of good, strong roots.
3/ SOIL TEMPERATURE
- Soil temperature is critically important for successful germination.
- Soil should be consistently warm before sowing warm season varieties direct in the garden.
- Cool soils cause many failures with seeds of summer plants (such as tomatoes) that are sown in early spring.
- Seeds can be sown in pots in a warm, sheltered spot and transplanted out into the garden when conditions are more favourable.
- A hint for raising temperature-sensitive seeds, such as petunias, in early spring is to sow into a 15cm diameter pot, water well and enclose the pot in a plastic bag that is sealed around the rim. Place the pot on a gentle source of heat - such as a hot water tank or a refrigerator. As soon as seedlings appear, remove the plastic bag and harden off seedlings outdoors.
- As soon as seedlings have emerged begin fertilising every week with half strength Thrive Soluble Plant Food. Don't apply to dry soil or mix.
- Once plants are established they can be fed fortnightly at regular strength.
Sowing direct into soil
Larger seeds are usually the most suitable for direct sowing.
- Flower seed examples are nasturtiums, marigolds, sweet peas and zinnias.
- Prepare the soil by mixing in some well-aged compost or manure.
- Add some Thrive Granular All Purpose plant food.
- Dig well so that the soil ends up with a fine, crumbly structure.
- Scatter seed thinly along the rows and cover with seed raising mix.
- Water well with a fine, gentle spray.
For further information, read more at www.yates.com.au