How to Grow Plants from Seed

Many plants with large seeds, such as Peas, Beans and Sweet Corn, are best sown directly where the plants are to grow. Plants with small seeds, such as Broccoli and Cabbage, should be sown into punnets or small pots of Yates Seed Raising Mix and the seedlings later transplanted into their final position. Seed packets will indicate whether direct sowing or growing seedlings is best. Seed-raising mix is recommended when growing seedlings in punnets, trays or pots, as it has a fine texture to improve the contact between the mix and the seed and help keep the seeds moist as they germinate.  

Before sowing seeds directly into the garden, remove any existing weeds and grasses. Then improve and enrich the soil by mixing in handfuls of Yates Dynamic Lifter Soil Improver & Plant Fertiliser. The rich organic matter and gentle nutrients will help give the new plants a great start. Seeds can be sown straight away into the Yates Dynamic Lifter improved soil – there is no need to wait.

When sowing seeds directly into potting mix, choose a well-drained pot and fill with a quality potting mix like Yates Premium Potting Mix with Dynamic Lifter.

Gently water to moisten the soil, potting mix or seed-raising mix. Watering before sowing rather than afterwards helps protect seeds from being swamped or washed up and out of the soil or potting mix.

Some seeds, such as Carrots, are best sown in furrows (rows). Other seeds, such as Sweet Corn and Zucchini, should be sown in individual holes. The seed packet will provide information on which sowing technique is best. 

Make the holes or furrows as deep as indicated on the seed pack (sow depth) and at the recommended spacing. Sowing depth is important, as seed sown too deep or too shallow may fail to grow. In general, larger seeds, such as Beans, are sown deeper than small seeds, such as Poppies. Some seeds, such as Cineraria, require light to germinate and are only just pressed into the surface of the soil or potting mix.

Sprinkle seeds along the furrows or drop a few seeds into individual holes. If too many seedlings emerge, they can be thinned later.

Cover with soil, potting mix or seed raising mix and gently firm down. This helps provide good contact with the seed.

When growing your own seedlings in pots or punnets, place them in a warm, brightly lit wind protected spot. Keep the seed raising mix consistently moist, but not wet. Seedlings can be transplanted into their final position once they’re large enough to handle.

For garden beds and pots, keep the soil or potting mix consistently moist. Lack of moisture can result in seeds failing to germinate or seedlings dying. The exception to this moisture rule is when growing Beans and Peas, as overly wet soil or potting mix can result in the seeds rotting. Just keep the soil only slightly moist.

Seedlings have a small root system and therefore limited access to moisture, so keep the soil or potting mix moist while they establish. This is particularly important for transplanted seedlings, which will also be suffering from transplant shock after being moved from a seedling tray or punnet into their final position.  

Young seedlings are particularly vulnerable to Snails and Slugs. As the seedlings emerge, protect them by lightly sprinkling some Yates Snail & Slug Bait around the plants.

Once the seedlings are established, usually after 4-6 weeks, start regularly feeding with an appropriate fertiliser. For example, Yates Thrive Vegie & Herb Liquid Plant Food for vegies and herbs, Yates Thrive Roses & Flowers Liquid Plant Food for flowering plants or Yates Dynamic Lifter Liquid for all plants including native plants. 

When sowing seeds, there are a few things to consider to get your seeds to germinate successfully, including sowing depth, light, soil moisture, and soil temperature.

The depth seeds should be sown at varies and usually depends on the size of the seed. Fine seeds (e.g., Lettuce and Snapdragons) should be barely covered; medium-sized seeds (e.g., Capsicum and Tomato) should be planted to a depth of about 6 mm; and large seeds (e.g., Peas and Beans) are planted more deeply, to a depth of about 25 mm. Seed packets include information on how deep to sow the seed.

Some tiny seeds need to be contacted by light for germination to occur.

Press seeds 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.

Examples of seeds that need light to germinate are: Ageratum, Alyssum, Antirrhinum, Aquilegia, Begonia, Campanula, Coleus, Feverfew, Impatiens, Petunia, Primula, Salvia, Stock, and Lettuce.

Some seeds need to be totally protected from light. To propagate dark-loving seeds cover with a sheet of newspaper or cardboard and remove after germination. 

Examples of seeds that need darkness to germinate are: Calendula, Cornflower, Delphinium, Forget-me-not, Gazania, Nasturtium, Pansy, Schizanthus, Sweet Pea, Verbena, Viola, and Coriander.

Fine seeds, such as Poppies, are sown shallowly and therefore are more prone to drying out. So, these should be watered frequently to keep the soil or potting mix moist.  

Large seeds (e.g., Sweet Peas, Sweet Corn, Peas, Beans and Broad Beans) need moist soil but not wet, so avoid watering while the soil remains moist or until the seedlings emerge. Do not pre-soak these seeds. 

Slow-to-germinate seeds (e.g. Pansy which take 21-28 days to germinate) need constant moisture and can't be allowed to dry out. 

After seedlings have emerged, water thoroughly but less frequently to encourage the development of good, strong roots. 

Soil temperature is critically important for successful germination. Some seeds need cool-to-cold soil to germinate, while others need warm soil (at least 20°C). Seed packets will indicate the best time of year for sowing in your climate. 

For seeds needing warm soil, wait until the soil temperature is consistent before sowing direct in the garden. Cool soils cause many failures with seeds of warmth-loving plants (e.g., Tomatoes and Beans) that are sown too early in spring.

To overcome inconsistent soil warmth, seeds can first be sown into seed trays and/or pots and grown in a warm and sheltered position. Once soil has warmed up, the seedlings can be transplanted out into the garden.

One way to protect seedlings from the cold is to grow them in pots and cover them with a plastic bag that is sealed around the rim to create a mini glasshouse. Then place the pot on a gentle source of heat – such as a hot water tank or a refrigerator until they have germinated. Once the seedlings have established, remove the plastic bag and harden the plants off outdoors.