A Florist Guide to Harvesting Flower Seeds

Collecting seeds from your garden flowers is a rewarding way to preserve favorite varieties, save money, and share plants with friends. This florist guide covers the essential techniques for harvesting seeds from different types of flowering plants.

General Principles of Seed Harvesting

Timing is Everything

The key to successful seed collection is harvesting at the right time. Seeds should be fully mature but not yet dispersed by the plant. Look for these signs:

• Seed pods or heads have changed color from green to brown, tan, or black

• Seeds rattle inside pods when shaken

• Petals have fallen and seed structures are dry

• Seeds easily separate from the plant when touched

Weather Considerations

Choose a dry, sunny day for seed collection, preferably after several days without rain. Morning harvest after dew has evaporated is ideal. Wet seeds are prone to mold and rot during storage.

Basic Equipment Needed

• Small paper bags or envelopes for each variety

• Fine-mesh strainer or sieve

• Scissors or pruning shears

• Labels and permanent marker

• Clean, dry containers for processing

• Magnifying glass (helpful for tiny seeds)

Seed Types and Harvesting Methods

Dry Pod Seeds

Many flowers produce seeds in dry pods that split open when mature.

Examples: Lupines, sweet peas, poppies, columbines, larkspur

Method:

1. Watch pods daily as they mature and begin to change color

2. For pods that split (dehiscent): Harvest just before they open completely, or tie small paper bags around pods while still on the plant

3. For non-splitting pods: Cut stems when pods are dry and brown

4. Place harvested material in paper bags and allow to dry completely

5. Shake or gently crush pods to release seeds

6. Separate seeds from chaff using a fine strainer

Fleshy Fruit Seeds

Some flowers develop into berries or soft fruits containing seeds.

Examples: Rose hips, ornamental peppers, tomato flowers

Method:

1. Allow fruits to fully ripen and soften

2. Cut open fruits and scoop out seeds

3. For wet processing: Place seeds and pulp in water, viable seeds will sink

4. Clean seeds thoroughly and spread on paper towels

5. Dry completely before storing (this may take several days)

Composite Flower Heads

Plants in the daisy family have complex flower heads with many small seeds.

Examples: Sunflowers, coneflowers, black-eyed Susans, zinnias, marigolds

Method:

1. Leave flower heads on plants until completely dry and brown

2. Cut stems about 6 inches below the flower head

3. Hang upside down in paper bags for additional drying

4. Rub dried heads between hands or use a coarse screen to separate seeds

5. Use winnowing (gentle blowing) to remove lightweight chaff

Capsule Seeds

These develop in small, dry capsules that open at the top when mature.

Examples: Snapdragons, petunias, campanulas, poppies

Method:

1. Watch for capsules to turn brown and develop openings at the top

2. Shake heads gently into paper bags

3. For stubborn seeds, cut entire stems and hang in paper bags

4. Seeds will fall naturally as capsules continue to dry

Feathery or Fluffy Seeds

Some seeds have attached fluffy structures to aid wind dispersal.

Examples: Clematis, milkweed, asters, Joe Pye weed

Method:

1. Harvest just as fluffy structures begin to form but before seeds blow away

2. Pull seeds gently from plants, keeping fluffy parts intact if desired for planting

3. For storage, remove fluffy parts by rubbing gently

4. These seeds often have short viability, so plant soon after harvest

Processing and Cleaning Seeds

Dry Processing

Most flower seeds can be cleaned through dry methods:

1. Spread harvested material on a clean, flat surface

2. Remove obvious plant debris by hand

3. Use screens with different mesh sizes to separate seeds from chaff

4. Gently blow away lightweight debris while retaining heavier seeds

5. Use tweezers for final cleaning of valuable seeds

Wet Processing

For seeds embedded in fleshy fruits:

1. Mash or blend fruit with water

2. Pour mixture through progressively finer strainers

3. Good seeds typically sink while pulp and bad seeds float

4. Rinse clean seeds thoroughly

5. Spread on paper towels and dry completely before storage

Drying and Curing

Proper drying is crucial for seed viability and storage life:

Air Drying Method

• Spread seeds in single layers on paper towels, screens, or newspaper

• Choose a warm, dry location with good air circulation

• Avoid direct sunlight which can damage seeds

• Turn seeds daily for even drying

• Most seeds require 1-2 weeks of drying

Testing for Dryness

Seeds are sufficiently dry when:

• They feel hard and don't indent when pressed with a fingernail

• They make a sharp sound when dropped on a hard surface

• They break cleanly rather than bending when bent

Storage Guidelines

Proper Containers

• Use paper envelopes, small glass jars, or airtight plastic containers

• Avoid plastic bags which can trap moisture

• Add silica gel packets for extra moisture control in humid climates

Labeling

Include on each container:

• Plant name and variety

• Date of harvest

• Location harvested

• Any special notes about the parent plant

Storage Conditions

• Keep in cool, dark, dry location

• Ideal temperature: 32-41°F (0-5°C)

• Humidity should be low (less than 50%)

• Most flower seeds remain viable for 2-5 years when properly stored

Variety-Specific Tips

Annuals

Cosmos: Easy to harvest from dried flower heads. Seeds are dark and elongated. Marigolds: Remove seeds from dried flower heads. Seeds are black and pointed. Zinnias: Harvest from completely dried centers. Pull seeds with attached chaff. Sunflowers: Cover heads with cheesecloth as they mature to prevent bird damage.

Perennials

Coneflowers (Echinacea): Leave some heads for wildlife, harvest others when dry. Delphiniums: Collect from pods before they split. Seeds are black and small. Hollyhocks: Gather seeds from disk-shaped pods around the main stem. Foxgloves: Tiny seeds fall from capsules when mature. Shake into bags.

Biennials

Sweet William: Small, dark seeds in capsules. Harvest when capsules turn brown. Canterbury Bells: Minute seeds in small capsules. Handle carefully to avoid loss.

Common Mistakes to Avoid

• Harvesting too early when seeds are still immature

• Collecting during humid or rainy weather

• Mixing varieties without proper labeling

• Storing seeds before they're completely dry

• Using airtight containers with inadequately dried seeds

• Exposing seeds to extreme temperatures during storage

Testing Seed Viability

Before planting stored seeds, test viability:

1. Place 10 seeds on moist paper towel

2. Seal in plastic bag and keep warm (70°F)

3. Check after appropriate germination time for variety

4. If fewer than 5 germinate, seeds may be too old or improperly stored

Final Tips for Success

• Start with easy varieties like zinnias, marigolds, and cosmos

• Keep detailed records of harvest dates and storage methods

• Share seeds with other gardeners to spread garden diversity

• Consider joining seed exchanges for rare varieties

• Always save more seeds than you think you'll need

• Remember that hybrid varieties may not produce plants true to type

Harvesting your own flower seeds connects you more deeply with your garden's cycle and provides the satisfaction of growing plants from seeds you've personally collected. With practice, you'll develop an eye for optimal harvest timing and the skills to build your own seed library for years of gardening enjoyment.