Key Points
Start geranium seeds indoors in January or February for spring blooms.Keep seeds warm (70–75°F), moist, and in bright light until they develop two true leaves.Transplant to pots, fertilize lightly, then harden off outdoors after the last frost.
The colorful blooms of geraniums are a nursery favorite in spring, but did you know you can grow geraniums from seed? These colorful flowers are grown both as perennials and annuals, and while you can pick them up once they’ve already started to bloom in the spring and summer, they’re simple to grow from seed—as long as you have time on your side.
You can expect a process that will take several months to grow geraniums from seed, yet the steps are straightforward, and the flowers are eager to grow successfully. As long as you buy your seeds early and start your geranium plants in late winter, you’ll have stunning blooms ready for the warm-weather planting season.
When to Plant Geraniums From Seed
Slow-growing geraniums should be planted during the coldest days of winter in January and February, which will give you plenty of time for fragrant blooms in the warm weather.
The seeds should be sown in seed trays and kept consistently moist. Be careful not to let the temperature go too high. Temperatures higher than 78°F could stop germination.
Before Getting Started
To help geraniums germinate and grow, there are a few additional supplies you may want to have on hand. Geraniums grow best in a seed starting mix, and they will germinate most successfully between 70°F and 75°F. A plant lamp can help maintain that temperature. Additionally, a fertilizer for houseplants can be used to help geraniums grow.
How to Grow Geraniums From Seed
Fill Seed Tray With Soil
Fill a seed tray with moistened potting soil, ideally a seed starting mix. Make sure each cell in the seed tray is no larger than two inches.
Sow a Single Seed in Each Tray
One seed should go in a section of the tray, and each seed should be covered with just a thin layer of the seed-starting soil. Cover the tray with plastic wrap to create the right environment for germination.
Put the Seed Tray in a Warm, Sunny Spot
Geraniums germinate in an environment that is 72°F with consistent moisture. This can be achieved with the combination of the covered tray and a sunny window, though you can also place the tray under a plant lamp to keep it at the right temperature.
Keep the Soil Moist
Because geraniums need consistent soil moisture, it’s necessary to keep a careful eye on the soil. If the soil begins to dry out, add moisture back in.
Look Out for Germination
There’s a wide range of germination estimates for geraniums. It could be as quick as just a few days, or it could take up to a month.
Continue to monitor the seedlings in the seed tray while they grow, allowing them to stay there until they have two true sets of leaves. Make sure they get full sun during this time.
Move the Plants form See Trays to Pots
Move the plants with two full sets of leaves from seed trays to pots. At this stage, they should have room to grow without being crowded by other plants. Repot them with new soil.
Fertilize the Young Plants
As the plants grow, fertilize them once a week with a standard houseplant fertilizer. Cut it to one-quarter strength to avoid burning the plants with fertilizer.
Move the Plants Outdoors
Geraniums will thrive in warm outdoor weather, but they need to be moved gradually. Wait until the last frost is done for the season, then move them outdoors to a covered area where they can acclimate to the less controlled setting.
Wait for the Blooms
By mid-spring, you should have the first of your vibrant and colorful geranium blooms, which will continue throughout spring and summer.
FAQ
How long does it take to grow geraniums from seed?
While geranium seedlings could pop up in just a few days, the seedlings grow slowly. You should expect blooms in thirteen to fifteen weeks.
Do geranium seeds need cold stratification?
Geranium seeds benefit from up to 60 days of cold stratification, which is being kept in cold, moist conditions to encourage germination.
Do geraniums like sun or shade?
Annual geraniums thrive in full sun, while perennials are more agreeable, growing in sun or shade.
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