Tips on saving your own seeds

Information sheet

Saving your own seed is a fun activity for early autumn and is a good way of increasing your seed supply for next year.

  • School term: Early Autumn, Late Summer
  • Level of experience: No experience needed
  • Subject(s): Science

Saving vegetable seed

Lettuces, spinach and swiss chard may have ‘gone to seed’.  This means the usually leafy vegetables have formed flowers on the end of a long stalk and then these flowers have formed seeds. It is possible for the children to collect these seeds and save them to sow next year. Children can collect the seed, dry them, sort them and then design and make their own seed packets to give or sell to parents.

Peas and beans that were not harvested in time for the end of term may have dried well on the plant. These will be ready to harvest for seed. The ‘Borlotti’ type of French bean can be dried to be eaten in soups and casseroles.

If you have space, leave one leek plant, an onion plant and maybe even a carrot and parsnip plant to over-winter. The next year they will flower and you can save their seeds. The children will see the flowers of these vegetables and recognise similarities within the family groups.

Some vegetables are easily cross pollinated by insects, so if you grow two varieties of the same vegetable at the same time, they are likely to cross-pollinate, resulting in a seed that is a mixture of both these bean varieties. Courgettes, pumpkins will cross-pollinate and their offspring will often produce misshapen fruits.

Vegetables that self-pollinate will most likely produce seed that is the same as its parent.

Saving seeds from herbs

Coriander, dill, parsley, basil, and chives can all be grown from saved seed. Basil is easily cross-pollinated, so if growing two varieties together only let one variety flower and seed.

Saving seeds from flowers

Autumn is a great time to collect the seeds from annuals in the school garden. Hardy annuals, such as cornflowers and marigolds, can be sown in September and will flower earlier in the summer term than spring-sown seeds. These flowers can attract beneficial insects into your school garden which is good for pest control and pollination.

See what hardy annuals you can sow each term here.

Important points to remember for seed saving

  • Only save seed from healthy looking plants. 
  • Collect seed when seed heads appear to be ripening. Unripe pods will not ripen once picked. 
  • Collect seed on a dry day to avoid fungal rot on seeds. 
  • Collect seeds directly from the plant into paper bags or into trays lined with newspaper. 
  • Label with name and date to avoid confusion later. 
  • Dry capsules and pods in a warm, dry place until the seeds are released. 
  • For fleshy seeds, such as tomatoes and cucumbers, ferment the seed for three days to remove the jelly like coating. Rinse in water then dry in a warm place. 
  • To separate seeds from the chaff (the remains of the seed capsule), place them in a tea strainer or garden sieve and blow away the chaff.

Care and storage of seeds

Store seeds in labelled paper envelopes or bags. They should be kept in a cool, dry place, within an airtight container if possible. Sachets of silica can be used to absorb any excess moisture.

Testing for viability

Some seeds are defective and will fail to grow. This means they were not fertile or fully developed. They may have been stored for too long or damaged by a pest or disease. To avoid sowing dead seeds you can perform this simple test to check the viability of your seeds.

Put medium to large seeds in a jar of water. Viable seeds will sink, whereas dead seeds will float to the surface.