How to Raise Seeds
A 3 minute read by Peter Worsp
There is nothing like the satisfaction of raising your own plants from seed or establishing new plants from cuttings. Additional benefits of course, are the cost saving and being able to grow your favourite plants which are not always available at the garden centre when you want them.
Raising seed is easy if you follow the simple steps outlined in this page.
Start with good seed. We recommend Yates seed because there is a wide selection to choose from with varieties to suit all seasons. In addition Yates has a number of excellent varieties not available in other brands.
Always use fresh seed as some seeds such as parsnip, lettuce and onion have a short life once the foil sachet packet is opened. It is preferable that seeds be used the same season the packet is opened. The seed in unopened foil sachets should remain viable for some years. Keep seed in a cool dry place. A sealed glass jar in a cupboard is best. Choose varieties to suit your area and the season.
A few species such as carrots, parsnips, turnips, peas and beans, are best sown directly in the soil, while most others are best sown in a tray to germinate and then transplanted out into the soil as young plants.
Raising young plants in punnets or small pots also saves time allowing better use of the garden space.
Raising seed in trays, punnets or pots
- Use a quality seed raising mix such as Yates Black Magic Seed Raising Mix
- If re-using old trays punnets or pots, ensure they have been washed thoroughly in order to remove all traces of soil which could be harbouring soil fungus diseases that attack germinating seeds.
- Fill the containers with seed raising mix, water, and allow to drain for 30 minutes or so.
- Some gardeners prefer to sow 2 –3 seeds in each cell of the punnet or pot, and then to thin out to 1 per cell / pot after germination.
- Other gardeners prefer to sow a number of seeds in a punnet/ pot / or tray and when they have germinated and have 1 true leaf (the next one to appear after the 2 seed leaves), they are carefully ‘pricked out’ into punnets, pots, or spaced out in a tray.
- With either technique, sow the seed to a depth of 2-3 times its thickness, or place on the surface and cover 2-3 times it’s thickness with seed raising mix.
- It is important that the mix in the sown punnets / trays, remains damp but not wet, until germination is complete, which takes from 1—3 weeks for most species. This is best achieved by placing in a small glass or polythene covered cloche, or by covering with a sheet of glass. A sheet of newspaper in addition will also help.
- Place in a warm sunny place in winter / early spring or in a shady place in summer
- As soon as germination is complete, remove glass or cover and allow ventilation. Keep moist but not wet, and ensure the young plants have good light.
- After another 2—3 weeks the young seedlings will be ready for transplanting into the garden.
Sowing direct into the soil
- This is the method for root vegetables such as carrots, parsnips, radish, beetroot, and Swedes, as well as peas, and beans. Other large seeds such as cucurbit family and sweet corn are also often sown direct in the soil where they are to grow.
- Sowing seed direct in the soil can be difficult in old diseased soil or clay soil where drainage is not good.
- Hence start by ensuring the soil has lots of compost added and is free draining.
- Another good idea is to create a shallow furrow about 30mm deep in the row where the seed is to be sown. Fill this furrow with seed raising mix.
- Sow the seeds at the spacing advised on the seed packet, and cover. Firm the surface gently to ensure seed—soil contact which also minimises drying out.
- Early in the season in colder districts it is common to cover with a cloche.
For more detail on seed raising, refer to Yates Garden Guide.
Troubleshooting if seeds don’t germinate
- Too wet - prevents oxygen getting to the seed, and increases fungal rots
- Too dry - seeds parts germinate and then die.
- Too cold - most seeds need moderate to warm temperature to germinate.
- Too hot - direct hot summer sun will kill germinating seeds
- Planting too deep - is usually too cold and wet as well.
- Planting too shallow - seeds likely to dry out
- Seed mix / soil to loose - insufficient moisture supply to the seed.
- Seed mix too firm - creates water-logging and stops oxygen getting to the seed.
- Presence of soil fungus diseases - in old gardens or dirty containers.
- Slugs and snails - will commonly attack seedlings as they germinate.
- Birds / cats / dogs
- Fertiliser burn - don’t apply fertiliser close to seeds.