The Complete Guide to Harvesting Seeds from Flowers

Harvesting seeds from flowers is one of the most rewarding aspects of gardening. Not only does it save money, but it allows you to propagate favorite varieties year after year and even develop new ones. This guide covers the how, when, and why for harvesting seeds from a wide variety of flowers.

1. General Principles for Harvesting Seeds

Before delving into flower-specific guidance, it’s essential to understand the principles that apply to all seed harvesting:

Timing

Seeds are mature when the plant has stopped flowering and the seed pods or heads are dry and firm.
Harvest too early, and seeds may be immature, resulting in poor germination.
Harvest too late, and seeds may fall to the ground, be eaten by birds, or lose viability.

Tools

Scissors or garden shears for cutting stems and pods.
Bowls, trays, or paper towels for collecting seeds.
Mesh bags or envelopes for drying and storage.
Labels and a permanent pen for keeping records.

Drying Seeds

Seeds must be completely dry before storage to prevent mold or rot.
Spread seeds on paper towels, newspaper, or trays in a dry, well-ventilated area, away from direct sunlight.
Small seeds may benefit from a fine mesh strainer or sieve to separate debris.

Storage

Store seeds in cool, dry, and dark conditions.
Use paper envelopes for large, dry seeds; airtight containers for very tiny seeds.
Label all containers with flower type and harvest date.
Seeds generally remain viable from 1–5 years depending on the species, storage method, and size.

2. Harvesting Seeds by Flower Type

Different flower types require different methods and attention. This section is divided by annuals, biennials, perennials, and flowers with tiny or unique seeds.

A. Annual Flowers

Annuals complete their life cycle in one growing season, making their seeds easiest to collect.

Marigolds (Tagetes)

Seed Pods: Long and thin, turning brown when mature.
Harvest: Pinch or cut dry pods, break them open, and remove the black, oval seeds.
Tip: Avoid letting pods open on the plant as seeds may scatter.

Zinnias (Zinnia elegans)

Seed Heads: Brown and dry; individual seeds are flat and elongated.
Harvest: Gently rub heads over a tray to release seeds.
Extra: Zinnias cross-pollinate, so saved seeds may produce mixed colors if different varieties are nearby.

Cosmos (Cosmos bipinnatus)

Seed Heads: Seed heads are small, dry, and dark brown.
Harvest: Shake or gently crush the heads over a bowl.
Tip: Cosmos seeds are very thin—handle carefully to avoid losing them.

Sunflowers (Helianthus annuus)

Seed Heads: Back of the flower turns yellow-brown; seeds plump.
Harvest: Cut the head, hang it upside down to dry, then rub seeds out.
Extra: Large seeds can be roasted or saved for snacks while leaving some for planting.

Nasturtiums (Tropaeolum majus)

Seed Pods: Pods resemble small peas; turn brown and dry.
Harvest: Collect before pods split naturally; allow to dry fully.
Tip: Nasturtium seeds germinate easily and can even be planted directly in the garden.

B. Biennial Flowers

Biennials take two years to bloom. Seeds are collected in the second year after flowering.

Foxglove (Digitalis purpurea)

Seed Capsules: Papery brown capsules that contain tiny seeds.
Harvest: Shake or tap capsules to release seeds; very small seeds benefit from a mesh bag to catch them.
Tip: Sow outdoors immediately or store carefully; seeds need light to germinate.

Sweet William (Dianthus barbatus)

Seed Pods: Small and dry; contain tiny black seeds.
Harvest: Snip off pods before they split; dry seeds fully before storing.
Extra: Sweet William seeds can remain viable for several years if kept dry.

Hollyhock (Alcea rosea)

Seed Pods: Round, dry “discs” containing multiple seeds.
Harvest: Cut entire flower heads; rub seeds out carefully.
Tip: Hollyhocks self-seed easily; saving seeds ensures variety preservation.

C. Perennial Flowers

Perennials bloom multiple years but can be harvested like annuals once seeds mature.

Echinacea (Coneflower)

Seed Head: Cone-shaped center turns brown and dry.
Harvest: Rub seeds off cone; they are small, brown, and slightly rough.
Extra: Echinacea seeds can be sown outdoors in fall or stratified for spring germination.

Lupines (Lupinus)

Pods: Seed pods split when mature; contain oval, hard seeds.
Harvest: Collect pods before they burst open; allow seeds to dry fully.
Tip: Lupine seeds often require scarification (scratching the seed coat) for germination.

Delphiniums

Seed Pods: Turn brown before splitting.
Harvest: Cut pods before they shatter, then remove small black seeds.
Extra: Seeds may require cold stratification to break dormancy.

Daylilies (Hemerocallis)

Seed Pods: Green at first, turning brown when mature.
Harvest: Pick pods before they split naturally.
Tip: Daylily seeds are slow to germinate; store for a short period before planting.

D. Flowers with Tiny Seeds

Tiny seeds need extra care to avoid loss.

Petunias

Seed Pods: Dry and start splitting.
Harvest: Gently shake or tap pods over a container.
Extra: Petunia seeds are light-sensitive; sow on surface, don’t bury deeply.

Impatiens

Seed Pods: Small pods that “pop” when mature.
Harvest: Catch seeds quickly as pods burst; dry immediately.
Tip: Impatiens seeds germinate quickly when sown indoors.

Poppies

Seed Capsules: Tan and rattle when mature.
Harvest: Cut capsules and shake seeds into a container.
Extra: Poppy seeds can remain viable for many years if stored dry.

Snapdragons (Antirrhinum majus)

Seed Pods: Dry and papery; contain many small seeds.
Harvest: Break open pods over a tray to release seeds.
Tip: Snapdragon seeds are very small; use a fine sieve to separate from debris.

E. Flowers with Unusual Seed Structures

Some flowers produce seeds in unique ways:

Milkweed (Asclepias)

Seed Pods: Long pods with silky fibers.
Harvest: Wait for pods to split; gently remove seeds from the fluff.
Tip: Fibers can be used for crafts; seeds are easy to plant outdoors in fall.

Larkspur (Consolida)

Seed Pods: Turn brown; contain several small, hard seeds.
Harvest: Cut before pods shatter; remove seeds carefully.

Nigella (Love-in-a-Mist)

Seed Capsules: Balloon-like capsules with black seeds inside.
Harvest: Cut mature pods, shake seeds into a container.
Tip: Seeds can be sown directly in the garden in spring.

3. Step-by-Step Harvesting Techniques

Inspect Plants Regularly
Check plants weekly as flowers mature to avoid losing seeds.
Cut Carefully
Use scissors or pruners to cut seed heads, leaving a bit of stem attached.
Drying
- Spread seeds or heads on a tray, in a warm, dry area.
- For very small seeds, place heads in a paper bag to catch falling seeds.
Cleaning
- Remove debris (chaff, stems, petals) by rubbing gently.
- Use a fine sieve for very tiny seeds.
Storage
- Ensure seeds are completely dry.
- Store in envelopes, jars, or packets with labels.
- Keep in a cool, dry, dark location.

4. Tips for Successful Seed Saving

Harvest on dry days; wet seeds may mold.
Avoid cross-pollination if preserving pure varieties.
Use rotation and plant diversity to maintain healthy seed stock.
Keep detailed records of flower varieties, harvest dates, and germination success.
Some seeds, like Lupines, Poppies, and Echinacea, may require cold stratification to break dormancy.

5. Quick Reference Table (Expanded)

Flower	Seed Ready When	Seed Type	Storage Tip
Marigold	Pods dry & brown	Black, smooth	Paper envelope, cool & dry
Zinnia	Flower head brown	Flat, elongated	Dry completely before storing
Cosmos	Petals fallen	Small, thin	Keep in dark, dry place
Sunflower	Back of head yellow-brown	Plump, black/striped	Remove seeds after drying
Nasturtium	Pods brown & dry	Round, smooth	Store dry, germinates easily
Echinacea	Cone brown & dry	Small, brown	Airtight container, cool
Lupine	Pods brown, before bursting	Hard, oval	Dry fully; scarify for planting
Poppy	Capsule tan & rattle	Tiny, hard	Collect carefully, dry first
Petunia	Pods dry, splitting	Tiny, light-sensitive	Sow on surface, avoid burying
Impatiens	Pods mature & pop	Tiny, round	Dry immediately
Foxglove	Capsules brown & papery	Tiny, light	Mesh bag; light needed to germinate
Hollyhock	Disc-shaped pods brown	Small, dark	Dry fully before storing
Milkweed	Pods split	Flat, attached to silky fiber	Store dry, separate fibers
Nigella	Pods brown, balloon-like	Small, black	Store dry, plant directly in spring