Seedheads, such as poppy, sedum and thistles, can be picked individually, or in stalks, which should then be laid out somewhere warm to dry.
Once they have dried out, it should be easy to open by hand or by gently crushing them to extract the seeds.
Fruits and berries
With soft fruits and berries, such as holly, blackberries and apples, you can extract the seeds by mashing them into a sieve and rinsing away the pulp, leaving the seeds behind.
These should then be allowed to dry out for a few days on a paper towel.
Nuts and fruits
Nuts, fruits and most other types of seed, such as damsons, conkers and chestnuts, that come from trees can be collected when they fall naturally, or picked from the tree when ripe.