Saving Nasturtium Seeds

Nasturtiums produce large, easy-to-handle seeds after their bright flowers fade. Unlike many dry-seeded flowers, the seed often drops while still somewhat green and finishes drying after collection. Saving seed is simple, but varieties flowering together may cross through pollinating insects, so home-saved offspring can vary in flower color, growth habit, or leaf form.

Explore the Nasturtium plant profile →

Choose Healthy Parent Plants

Select vigorous nasturtiums with desirable flower color, plant habit, leaf form, bloom time, and overall performance.

Know the Variety

Trailing, climbing, compact, and variegated types can differ substantially in growth.

Choose Open-Pollinated Plants for Predictability

Open-pollinated varieties are generally easier to maintain consistently than hybrids.

Expect Hybrid Offspring to Vary

Seed from hybrids may produce different flower colors, plant sizes, or foliage traits.

Understand Pollination

Bees and other insects can move pollen among compatible nasturtium flowers.

Expect Crossing in Mixed Plantings

Different varieties blooming together may produce genetically mixed seed.

Use Isolation if Purity Matters

Greater separation, timing, or controlled pollination may be useful when maintaining a particular line.

Label Seed Parents Early

Mark desirable plants before flowering ends so their traits remain known.

Leave Selected Flowers to Mature

Do not remove every spent flower if seed saving is planned.

Watch Seed Form After Flowering

Large rounded seed structures develop where flowers were attached.

Expect Seed to Drop Before Fully Dry

Nasturtium seed often falls from the plant while still pale or slightly green.

Check Beneath Plants Frequently

Mature seed can collect on the soil under spreading vines.

Harvest Seed From the Plant When Loose

Seed that detaches easily is generally more mature than seed that must be pulled forcefully.

Do Not Collect Soft Rotting Seed

Seed that has begun decomposing on wet ground may not store well.

Harvest During Dry Conditions When Possible

Seed collected from dry soil is easier to finish drying safely.

Keep Varieties Separate

Use different labeled containers for each intended seed lot.

Finish Drying After Harvest

Spread seed in a single layer in a dry ventilated location.

Do Not Seal Fresh Seed Immediately

Nasturtium seed may contain substantial internal moisture when first collected.

Turn Seed During Drying

Occasional movement helps expose all sides to airflow.

Provide Good Ventilation

Air movement helps prevent mold while the thick seed dries.

Avoid Excessive Heat

Do not attempt to force drying with high temperatures that could damage viability.

Watch for Shrinking

Nasturtium seed often becomes smaller and more wrinkled as it dries.

Allow Plenty of Drying Time

Large fleshy seeds generally take longer to dry than thin dry flower seed.

Inspect Seed Before Storage

Remove seed that is moldy, soft, badly damaged, or obviously decaying.

Label the Storage Container

Record variety, flower color, harvest year, and any useful parent information.

Keep Years Separate

Separate seed lots make age and germination performance easier to track.

Store Cool and Dry

Stable low-humidity storage helps preserve viability after the seed is fully dry.

Protect Seed From Moisture

Thick seed can mold if storage conditions become humid.

Test Older Seed

A germination test can show whether stored nasturtium seed remains useful.

Expect a Hard Seed Coat

Dried nasturtium seed has a firm outer coat that can slow water uptake during germination.

Use Scarification if Appropriate

Light abrasion or nicking can help some older or hard seed absorb water more readily.

Do Not Damage the Embryo

If scarifying, work only on the outer coat and avoid deep cuts.

Expect Volunteer Plants

Seed left on the ground may sprout naturally when conditions are suitable.

Use Volunteers Carefully for Variety Maintenance

Parentage can be uncertain when several varieties flowered together.

Expect Flower Color Variation

Open pollination can create new color combinations in the next generation.

Select for Desired Growth Habit

Save from compact, trailing, climbing, or variegated plants according to your goals.

Save From Several Plants

Using multiple suitable parents preserves broader diversity.

Keep Selection Records

Record flower color, vine length, leaf traits, bloom duration, heat tolerance, and vigor.

Practical Takeaway

Save nasturtium seed by selecting desirable plants, collecting large mature seeds as they loosen or fall, drying them thoroughly with good airflow before storage, and labeling each seed lot with variety, year, and parent information.