Collecting seeds: what to look for before harvesting

Collecting Seeds: What to Look for Before Harvesting

In this lesson, I'll share my tips on finding the best time to collect your seeds, and we'll explore the wonderful diversity of seedheads you might come across.

How do you know when your seeds are ready to collect?

• Seeds often ripen around two months after flowering as a rough guide, but the key is to be vigilant.
• Seeds need to be really dry.
• The plant will be starting to look brown.
• If you gently shake the plant, seeds will start to fall off.
• Don't leave it too long as seeds will start to disperse and blow away.
• Sweet peas take a long time as they need to be really brown and crispy. If too early the pods will be brown and the seeds green. You can bring them into the greenhouse to dry naturally and ripen further, even all winter.

Choose a dry day to collect your seeds. The seedheads need to be really dry otherwise the seeds won't keep and risk going mouldy.

Plants have many methods of dispersing seed, such as:

• dropping to the ground
• blowing away in the wind
• being eaten by birds or other animals
• being sticky to cling to animals
• having pods that open explosively to expel the seeds.

Examples of the diversity of seedheads:

• poppy – pepperpot-like
• Verbascum – single spires
• Leonurus – branching spires
• honesty – papery pods
• sweet peas – furry pods.

Many seedheads are beautiful or architectural and will provide winter interest, and also food and habitat for wildlife, if left standing until spring.

Plant Directory

Centranthus ruber 'Albus'

Red valerian (white form)

Hardy semi-evergreen perennial

Caprifoliaceae

Cynoglossum 'Mystery Rose'

Chinese forget-me-not 'Mystery Rose'

Hardy annual or biennial

Boraginaceae

Lathyrus odoratus 'Matucana'

Sweet pea 'Matucana'

Hardy annual

Fabaceae

Leonurus sibiricus

Siberian motherwort

Hardy annual or biennial

Lamiaceae

Lunaria annua 'Corfu Blue'

Honesty 'Corfu Blue'

Hardy annual or biennial

Brassicaceae

Nigella damascena

Love-in-a-mist

Hardy annual

Ranunculaceae

Papaver somniferum

Opium poppy

Hardy annual

Papaveraceae

Verbascum chaixii 'Album'

White nettle-leaved mullein

Hardy semi-evergreen perennial

Scrophulariaceae