Geraniums produce seeds readily, and collecting them is straightforward once you know what to look for. The entire Geraniaceae family is defined by its distinctive beak-like fruit, which holds five seeds each tipped with a tapering awn that curls or bends as it dries, flinging seeds away from the parent plant. Whether you grow true geraniums (cranesbills) or the common garden plants most people call geraniums (which are technically pelargoniums), both set seed and can be grown from it, though the process and the challenges differ between the two groups.
True Geraniums Versus Pelargoniums
Before getting into seed collection, it helps to clear up one of the most common points of confusion in the gardening world. The plants sold as “geraniums” at most garden centers, the ones with thick stems, rounded leaves, and bright red or pink flower clusters in pots and window boxes, are almost always pelargoniums (Pelargonium × hortorum and related hybrids). True geraniums, also called cranesbills, are a separate genus of mostly hardy perennials with smaller, more open flowers and deeply lobed leaves. Both belong to the family Geraniaceae and both produce seeds with the same basic beak-and-awn structure, but they behave quite differently when it comes to seed dormancy, germination, and how easy they are to grow from seed.
This distinction matters because advice that works perfectly for hardy cranesbill geraniums can fail completely for pelargonium hybrids, and vice versa. When this article says “geranium,” it means the true Geranium genus unless stated otherwise. When it means the common garden bedding plant, it will say “pelargonium.”
What Geranium Seeds Look Like and How They Disperse
The fruit of a geranium looks nothing like what most people picture when they think of a seed pod. After the petals drop, a long, pointed structure develops at the center of the flower, shaped roughly like a crane’s bill (hence the common name “cranesbill”). This beak-like column holds five seeds arranged around its base, each attached to a thin, elongated strip called an awn. As the fruit dries, tension builds in the awns due to a two-layered internal structure: a stiff outer layer and a moisture-sensitive inner layer whose cellulose fibers contract as they lose water.1PubMed Central. Hygroscopic movements in Geraniaceae: the structural variations that are responsible for coiling or bending When enough tension accumulates, the awns snap upward, catapulting the seeds away from the plant. In meadow cranesbill (Geranium pratense), this ballistic dispersal can fling seeds several meters from the parent plant.2Journal of Ecology. Biological Flora of Britain and Ireland: Geranium pratense
This explosive mechanism is what makes timing so critical for seed collection. You have a narrow window between the moment seeds are mature and the moment they launch themselves across your garden. If you wait until the beak looks fully brown and dry, you may find it has already fired its payload.
When and How to Collect Seeds
Watch the seed heads closely starting about three to four weeks after flowering. The beak will transition from green to tan or brown as it ripens. The trick is to catch it just before the awns separate and coil. One reliable method is to tie a small square of mesh fabric, cheesecloth, or an old stocking over the developing seed heads while they are still greenish-brown. The mesh lets air circulate but catches the seeds when they eject. Check every couple of days and harvest the mesh bags once the beak has fully dried and split.
If you prefer a more hands-on approach, you can snip the entire seed head off the plant once it starts turning brown but before it has fully separated. Place the cut stems upside down in a paper bag in a warm, dry spot. Within a few days, the awns will dry completely and release their seeds into the bag. Avoid plastic bags, which trap moisture and invite mold.
Each flower typically produces up to five seeds, though not every ovule develops fully. How many seeds you get depends heavily on how well the flowers were pollinated. Research on spotted geranium (Geranium maculatum) found that plants given extra pollen by hand produced about one and a half times more seeds than plants relying solely on natural pollinator visits.3PubMed. Determinants of seed production in Geranium maculatum Outcross pollen (from a different plant) was far more productive than self-pollen, yielding two to four times as many seeds in some cases.4American Journal of Botany. Gender variation and sexual differences in reproductive characters and seed production in gynodioecious Geranium maculatum The practical takeaway: if you grow only one geranium plant in isolation, you may get disappointing seed set. Growing several plants near each other, or hand-pollinating with a small brush, dramatically improves your harvest.
Understanding Seed Dormancy
Freshly collected geranium seeds often will not germinate right away, even under perfect conditions. The reason is a tough, waterproof seed coat that physically blocks water from reaching the embryo inside. This is called physical dormancy, and it varies enormously across the Geraniaceae family. A large study testing over 29,000 seeds from 35 species found that the proportion of waterproof seeds at maturity ranged from zero to one hundred percent depending on the species.5Seed Science Research. Physical dormancy in Geraniaceae seeds Most true geraniums and many pelargoniums fell into the highest dormancy category, with more than 80 percent of their seeds impermeable to water at maturity. A few succulent pelargonium species had no dormancy at all.
Some species also layer a second type of dormancy on top of the waterproof coat. Herb Robert (Geranium robertianum), for example, combines a physical seed coat barrier with a physiological dormancy that requires a period of winter chilling before the seed is internally ready to germinate.6PubMed Central. A combined physical and physiological dormancy controls seasonal seedling emergence of Geranium robertianum This double lock ensures seeds germinate only when conditions are right, which is great for the plant’s survival in the wild but inconvenient if you want seedlings on your schedule.
Breaking Dormancy Before Sowing
Because the waterproof seed coat is the main barrier for most geranium species, scarification, which means creating a small opening in the coat so water can enter, is the most important pre-treatment. Research on several Geranium species identified a specific weak spot near the micropyle (the tiny pore at one end of the seed) where the coat is structurally different from the rest. Heat exposure causes cells in this region to change and eventually rupture, forming what researchers call a “water gap” that lets moisture in.7Annals of Botany. Identification and characterization of the water gap in physically dormant seeds of Geraniaceae, with special reference to Geranium carolinianum
You can replicate this at home in several ways:
- Sandpaper: Gently rub seeds on fine-grit sandpaper until you see a slightly lighter spot on the coat. Be careful not to sand through to the embryo.
- Nick with a blade: Use a sharp knife or nail clippers to chip a tiny piece off the seed coat opposite the pointed end. This is precise but fiddly with small seeds.
- Hot water soak: Pour water that has just stopped boiling over the seeds and let them soak as it cools for 12 to 24 hours. The heat can trigger the natural water-gap mechanism.
For species that also have physiological dormancy, scarification alone is not enough. You will need to follow it with cold stratification: place the scarified, moistened seeds in a sealed bag of damp sand or vermiculite in the refrigerator for four to six weeks. This mimics winter and satisfies the internal chill requirement.
Storing Seeds Before You Are Ready to Sow
If you collect seeds in summer but do not plan to sow until the following spring, storage conditions matter more than you might expect. Research tracking seeds over multiple years found that dry indoor storage gradually broke down the waterproof coat in some species. Erodium cicutarium, a close relative in the same family, went from 95 percent impermeable seeds to fully permeable seeds after five years of room-temperature dry storage.5Seed Science Research. Physical dormancy in Geraniaceae seeds Other species, including Geranium pratense and some pelargoniums, showed no change in dormancy over the same period. In a separate study, seeds of annual geraniums stored dry lost both their physical and physiological dormancy over time, while seeds buried in soil outdoors stayed impermeable and viable with no seasonal shift in their ability to germinate.8Seed Science Research. Germination ecology of eleven species of Geraniaceae and Malvaceae, with special reference to the effects of drying seeds
What this means in practice: store collected seeds in a cool, dry place in paper envelopes or small glass jars. If you store them for more than a year or two, test a small batch before committing your whole stash to a seed tray. Some species will have lost their dormancy naturally during storage and germinate easily. Others will still need scarification. You will not know which camp yours falls into until you try.
Sowing and Growing Geranium Seedlings
Once dormancy is broken, true geranium seeds germinate best in a consistently moist, free-draining seed-starting mix at temperatures around 18 to 22 °C (roughly 65 to 72 °F). Sow seeds about 5 mm deep, cover lightly, and keep the surface damp but not waterlogged. Germination times vary widely by species, from a couple of weeks for easy germinators to two months or more for deeply dormant wild species. Patience is part of the process.
Pelargonium hybrids, the common garden “geraniums,” follow a slightly different path. Their seeds are widely available commercially already scarified and primed, which skips the dormancy problem entirely. These germinate fairly reliably in about 7 to 14 days at warm temperatures. If you are collecting your own pelargonium seeds from hybrid plants, be aware that the offspring will not look like the parent. Most bedding pelargoniums are F1 hybrids, and their seeds produce a random assortment of traits. Growing pelargoniums “true” from seed requires open-pollinated or seed-strain varieties specifically bred for that purpose.
Young geranium seedlings are vulnerable to damping-off, a fungal disease that rots stems at the soil line and kills seedlings quickly. Research found that Pythium, one of the main damping-off organisms, can actually be stimulated by very low concentrations of certain fungicides, leading to worse disease rather than better control.9PubMed. Sublethal Doses of Mefenoxam Enhance Pythium Damping-off of Geranium The best prevention is cultural rather than chemical: use sterile seed-starting mix, ensure good air circulation, avoid overwatering, and do not crowd seedlings.
Giving Seedlings a Strong Start with Soil Fungi
An often-overlooked factor in growing geraniums from seed is what is living in the soil. Beneficial mycorrhizal fungi form partnerships with plant roots, helping them absorb phosphorus and other nutrients in exchange for sugars. Research on Geranium robertianum found that plants grown with mycorrhizal inoculum from nutrient-poor forest soils produced significantly more root and shoot mass than uninoculated plants, especially when phosphorus was scarce.10PubMed. Role of mycorrhizal fungus origin in growth and nutrient uptake by Geranium robertianum Interestingly, introducing mycorrhizal fungi at the earliest possible growth stage made the biggest difference: pre-inoculated pelargonium plants produced about 27 percent more cuttings and nearly twice as many flowers compared to controls.11HortScience. Plant Growth Stage for Geranium Inoculation with Vesicular–Arbuscular Mycorrhizal (VAM) Fungi
There is a catch, though. One study found that the presence of mycorrhizal spores in the soil actually decreased seed germination, even though surviving plants grew larger afterward.12PubMed. Effects of arbuscular mycorrhizal fungi and maternal plant sex on seed germination and early plant establishment A reasonable strategy is to germinate seeds in sterile mix, then transplant seedlings into soil that contains mycorrhizal inoculant once they have their first true leaves. This avoids any germination interference while still giving the young plants a fungal growth boost during the stage when it matters most.
Why Hybrid Pelargonium Seeds Are a Gamble
If you grow the classic red zonal pelargoniums on your patio, you may notice seed heads forming after the flowers fade. These seeds are perfectly viable, but growing them out is a lottery. Most ornamental pelargoniums are bred by crossing two carefully selected parent lines, producing an F1 hybrid with uniform flower color, compact habit, and heavy blooming. When that hybrid sets seed through open pollination, the resulting offspring shuffle the parent genetics unpredictably. You might get plants with different flower colors, leggier growth, or fewer blooms than the parent.
This is not a reason to avoid trying. Growing pelargoniums from saved seed can produce surprising and occasionally lovely plants. It is just not the route to take if you want an exact copy of what you already have. For that, you are better off taking cuttings, which produce genetic clones of the parent. Seed strains bred specifically for uniformity when grown from seed, such as the Maverick or Orbit series, are available from seed companies and behave much more predictably.
Growing Hardy Geraniums from Seed in the Garden
True cranesbill geraniums are among the most rewarding perennials to grow from seed, though they reward patience more than urgency. Many gardeners sow them outdoors in autumn, letting winter’s cold and moisture do the scarification and stratification work naturally. Simply press the seeds into the soil surface of a prepared bed or pot, cover lightly with grit, and leave them exposed to the elements. Germination happens in spring as temperatures warm and the seed coat has been broken down by freeze-thaw cycles and microbial activity.
If you prefer spring sowing, do the scarification and cold-stratification steps described earlier indoors during late winter. Move the treated seeds to a warm, bright spot in early spring and expect erratic germination. Unlike vegetable seeds that pop up uniformly, hardy geranium seeds straggle in over weeks. Do not discard a tray that seems slow; seeds may still be emerging a month or two after the first ones appeared.
Once established, most true geraniums self-sow freely if you let the seed heads mature on the plant. In fact, some species like Herb Robert and dove’s-foot cranesbill (Geranium molle) can become mildly weedy in favorable conditions. If you want to prevent this, deadhead spent flowers before the beaked seed pods have a chance to form and dry. If you enjoy the naturalized look, simply let them do their thing and pull out extras where they are not welcome.
Common Mistakes When Growing Geraniums from Seed
A few pitfalls trip up even experienced gardeners when they first try growing geraniums from seed:
- Skipping scarification: Sowing unscarified seeds of true geraniums and expecting quick results is the single most common frustration. Without breaking the waterproof coat, the seeds may sit in the soil for a full year or more before enough natural weathering occurs to let water in.
- Overwatering after sowing: Geranium seeds need consistent moisture but rot easily in waterlogged mix. A misting bottle is gentler than a watering can, and bottom-watering by placing seed trays in a shallow dish of water works well.
- Expecting uniformity from hybrid pelargoniums: As discussed, saved seed from F1 hybrid pelargoniums produces variable offspring. This is genetics, not a growing mistake, but it catches people off guard.
- Sowing too deep: Small geranium seeds need light to germinate in many species. A thin covering of vermiculite or fine grit is enough. Burying them deeply reduces germination rates.
- Giving up too early: Some species simply take a long time. If you have scarified and stratified properly, give the tray at least 8 to 10 weeks before concluding nothing is happening.
Seed Viability and How Long Seeds Last
Geranium seeds are generally long-lived compared to many garden plants, though viability depends on the species and how they are stored. The same study that tracked dormancy changes over five years found that some species maintained both their dormancy and their viability through the entire period in dry room-temperature storage.5Seed Science Research. Physical dormancy in Geraniaceae seeds Seeds buried outdoors in soil stayed viable even longer, with the waterproof coat acting as a kind of natural preservation system.8Seed Science Research. Germination ecology of eleven species of Geraniaceae and Malvaceae, with special reference to the effects of drying seeds In the wild, this is what creates a “seed bank” in the soil, a reserve of buried seeds that germinate over multiple years, ensuring the species persists even if one year’s seedlings fail.
For home gardeners, this means you do not have to rush to use freshly collected seeds. A packet stored in a cool, dry drawer should remain viable for at least two to three years and often longer. That said, germination rates gradually decline over time, so fresher is generally better. If you are testing old seeds, sow extra and thin later rather than counting on every seed to sprout.