Help and Information
Why grow from seed?
The reasons for growing vegetables and flowers from seed are many and varied. There is no doubt that seed is the only way to obtain many of the less common types, but economics, satisfaction and control over how and when they are grown also rates highly.
When we purchase seedlings they invariably come in punnets and need to be transplanted. This transplanting has minimal effect on some plants, but in others can lead to transplanting shock, retarded growth and delayed maturity.
At home it is best, where desirable and practical, to sow as many types as possible directly where they are to grow. This can result in sturdier plants with better root systems than those transplanted.
Direct sown crops will often mature at the same time as a similar crop that was transplanted! However in some instances sowing into trays or punnets indoors is essential to overcome low temperatures etc that prevail outside, eg tomatoes and capsicums in cool areas.
When direct seeding into the garden is chosen, ensure that the soil temperature is satisfactory. Follow any special instructions noted on individual seed packets. Observe notes on season, sowing depth, soil temperature, light requirements, chilling needs etc.
Sowing too early, particularly with many of our summer growing plants will lead to poor germination, with the seed inevitably being blamed. Check the soil temperature along with the requirements noted on our seed packets.
Seed should be sown into a fine soil that has already had manures, composts and fertilisers added and mixed well throughout the top 15 cm. It should be well worked to break up clods and lumps. In very heavy soils, the addition of coarse sand can improve its structure in the short term, while regular dressings with organic matter will help long term. Sandy soils require regular applications of organic material for both moisture and nutrient retention.
Never prepare the outdoor seedbed when the soil is sticky and hard to work. While it can be frustrating, it is better to be patient to obtain a better final result.
Remember that for seed to germinate satisfactorily it requires moisture, air and warmth. A fine moist soil allows for good contact between seed and soil. Lumpy or coarse soils have poor seed contact and may contain air pockets that can dry out the tiny tender roots of the just germinated seedling.
The depth of sowing is often the subject of much discussion, but is probably the least important issue if every thing else has been observed. As a rule of thumb in the Vegie garden, smaller seed can be sown around 1 cm. deep, while larger seed like Pumpkins, Peas, Beans and Sweet Corn can be safely sown 3 to 5 cm. deep. Some flower seeds however do require special conditions like complete darkness or the presence of light to give satisfactory results. In such cases we note this in our growing instructions. Ignore the often given advice of sowing twice the depth of the seed size.
It is important that the seedbed be firm, but not hard, and definitely not too soft and fluffy. The top few centimetres should be friable and easily penetrated by the young emerging shoots and roots.
Many good garden soils are quite satisfactory as a seed covering in the outdoor seedbed, but where crusting is likely to occur, cover the seed drill or row with a 50/50 mix of fine Peat Moss and soil. Pressed firmly down, it will prevent crusting, maintain moisture around the seed and allow for easy emergence.
The seed should be watered after sowing in warm weather, always using a light spray to avoid any compaction that can occur with heavier watering.
When laying out the area to be sown it is best to use a string line to mark out the row. While this allows for a neat garden, more importantly it allows for easy location of young seedlings among weeds that invariably occur.
Mark out the row with the back of a rake, or the corner of a hoe. Sow the seed sparingly, either by hand or making use of a “Seed Sower” for more accurate placement. Some seeds are quite difficult to see well when sowing. In such cases a little Talcum powder mixed with the seed make the seed more obvious. Always sow more seeds than are required, even with large seeded and good germinating crops, as many factors can reduce the final number of plants that survive.
Thin excess plants as soon as it is practical to handle them, initially to half the final spacing. Water well some hours beforehand for easy removal and lightly when the thinning is complete to settle the soil around the roots of any disturbed plants.
Use fresh seed each season for reliable results, even though they may be well inside their “Use By” date. Storage conditions between seasons are not always ideal and lead to less than satisfactory results. This is particularly the case in hot and humid areas.
Sowing outdoors is not always possible due to temperature, space, season or perhaps some special requirement. In such cases containers of some type must be used. In the home garden situation polystyrene boxes are ideal, although seedling punnets, egg cartons, pots or any other container that is capable of holding well drained soil will suffice.
Sowing into Containers
Seedlings purchased from the local nursery are invariably grown in small shallow punnets. These are used by the nurseyman for both economic and handling reasons, and are quite satisfactory when regularly fed and tended as the nurseyman will ensure.
Sowing the seed into containers is generally similar to in the open ground, noting any special requirements. Rows are preferred to scattering, and seedlings will need to be thinned out to prevent possible disease problems and to ensure the development of strong solid plants not deprived of light or food caused by overcrowding.
At home a deeper and larger container will allow the gardener to produce a better seedling. Choose a tray 8 cm. deep(shallow polystyrene fruit boxes are ideal), and fill with a high quality free draining sterilised potting mix. If "seed raising" mixes are used remember they are designed only for good germination, not for the continued growth of the plant. These seed raising mixes are very low in food and will require frequent liquid feeding to obtain satisfactory seedling growth.
Remember that most garden soil is rarely satisfactory in containers due mainly to compaction problems and the risk of disease.
Many seedlings do not transplant well. This is usualy noted on the seed packet. In these cases the use of individual cells for each plant is recommended. Use old yoghurt containers, cut down milk cartons, plastic drink cups or Jiffy pellets.
Where trays are used, don't try to cram too many seedlings into it. Allow at least 5 cm between plants to help prevent disease and to ensure adequate light and food is available. Just as importantly, plenty of space between seedlings will ensure a minimum of root disturbance at transplanting.
At sowing, fill the container to within 1/2 cm. of the top. Sow the seed as recommended into the previously moistened mix and place in a warm well lit position. Always water the container after sowing to ensure good soil-seed contact, using a very fine spray to minimise disturbance.
Strong light after emergence helps to avoid soft spindly plants.
Warmth and moisture can be retained in the container or pot by covering with a clear plastic bag. Often no further watering will be required but check frequently. Remove the bag soon after germination or the young seedling may suffer from lack of light and be prone to various rotting organisms.
Always ensure that the young growing seedlings have good ventilation.
Transplant seedlings when they have developed some size, ensuring that they have been hardened off over a week or so beforehand by progressively exposing them to outside conditions. Water thoroughly 12 hours before removal from their container, keeping as much soil as possible on the roots to avoid transplanting shock. Place the seedling into the fully manured and fertilised bed where it is to grow to maturity, watering each individual plant to obtain good contact between the roots and the soil.