Seed Collection

See The Garden, RHS February 2013, pp 58-62 for guidance on seed collection techniques; see also RHS, The Garden, September 2019, pp. 49-51.

Seeds to save: annually flowering plants such as cosmos, nicotiana, nigella or cleome.

Semi-hardy seeds to save: calendula.

Collecting Seeds

Collect at the moment of dispersal.  You can tie a bag over the seedhead before it has ripened.

  • gather on dry days.  If it has rained, wait a few days before collecting.
  • don’t forget to write the name of the plant on the storage bag, along the with the date you collected the seed.
  • don’t store seeds in plastic bags; use paper envelopes instead.

Scarifying Seeds

This is when you scratch the surface of the seed coat.  The easiest way to do this is to line the inside of a glass jar with a piece of rough sandpaper – add the seeds and shake a bit.

Soaking Seeds

Some seeds can be soaked up to 6 hours before planting – such as narsturtium and peas.


This is when seeds are combined with moist potting compost and subjected to a period of cold or warm to simulate environmental conditions needed for germination.