You can grow geraniums (Pelargoniums) indoors as houseplants all year-round or overwinter them inside during the cold months and return them outdoors again in spring. Either way these plants will keep producing bold, beautiful blooms all the way along.
If you want to keep geraniums dormant for the winter in storage, see How to Overwinter Geraniums for tips and instructions.
Grow Geraniums Indoors
Geraniums (Pelargoniums) are not only inexpensive, vibrant bloomers, but long-living annuals as well. While they cannot tolerate cold conditions, with some basic care indoors, you can keep them blooming and reblooming in your home all year-round.
Geranium | Genus: Pelargonium
The Geraniaceae family of plants includes Geranium (430 species), Pelargonium (280 species) and Erodium (80 species).
Pelargonium common names include: zonal, scented, ivy-leafed, and Martha Washington geraniums.
Misnomer: We commonly refer to Pelargoniums (Pelargonium x hortorum) as ‘geraniums’ but that’s not their botanical name. At this point it’s more like a misplaced nickname that won’t go away.
Geranium (Pelargonium) Growing Tips
Long-living flowering annual (tender perennial)
• Hardiness zones: 10 to 11
• Full sun
• Soil: well-draining
• Propagation: grow from cuttings or division
• Cold climates: overwintering tips
• Grow indoors or outdoors
- Getting Started
- Light & Temperature
- Deadheading & Pruning
- Grow Outdoors Again
To grow geraniums indoors, you can start with a new potted plant from the store or use the same plants you have been growing outdoors in the summer.
If you do want to use outdoor plants, start with these instructions for overwintering geraniums as houseplants to ensure they are bug-free and disease-free before they enter your house.
The reason these make good houseplants is the same reason we love them outside: they are consistent, bold, beautiful bloomers. A geranium indoors may provide flowers continuously for months (and months). And then, after a natural rest period with few or no flowers, they will bloom all over again.
Geraniums do not tolerate excess moisture. If they sit in damp potting mix for too long, they rot.
So, your job is to ensure you choose a flower pot that has drainage holes on the bottom and a saucer to catch surplus water (which you will empty after watering).
For pot size, choose something a couple inches wider than the root ball. The roots are quite fine and the plant won’t care if it’s a bit snug in the pot.
It may be two years or more before you’ll need a larger pot.
Because geraniums do not like being soggy, a lightweight potting mix suitable for flowering plants is your best option.
Light & Temperature
Sun is key to ensure flowering. If you can, choose a south or west-facing location that provides at least six hours of light each day.
For temperature, the sweet spot is between 55°- 65°F (12°-18°C).
If it gets too hot, the plant will not flower.
How often your geranium will need watering will depend on the growing conditions.
The best approach is to water occasionally but generously.
Use your finger tip or a moisture meter and water when the top inch of potting mix is dry.
Water deeply to completely saturate the potting mix, allowing the surplus to pool in the saucer.
After 30 minutes, empty the saucer.
Do not water again until the top inch is again dry. This could be days or even weeks, depending how hot and humid it is in your home.
If the air is dry, figure out ways to increase the humidity. This has tips on what does and does not help increase the humidity levels indoors. Hint: drip trays and misting don’t work!
This simple tagging system makes it easy to know what your houseplants need.
If you notice tiny mosquito-like insects flying around your houseplant, it may be fungus gnats.
You can trap the adults using these sticky yellow cards which will in turn prevent females from laying eggs.
Deadheading and Pruning
Geraniums lose (and grow) a lot of leaves. Your maintenance tasks will include removing any yellow or brown leaves on a regular basis and snapping off old flower stems after blooming. Add everything to your kitchen compost.
As geraniums age, the stems become thick and leggy. You can let yours get tall or routinely trim them back to leaf nodes (where leaves grow out of the stems) to encourage a bushier appearance.
You can also take cuttings using these instructions to start new plants.
Depending on the health and age of your plant and the potting mix, you may never need to add fertilizer.
I kept several containers of geraniums for years by a drafty, west-facing window in commercial potting mix and never fertilized them. I did move them to larger flower pots after the first few years, when the roots started growing out of the drainage holes, and provided fresh potting mix at that time, and that was enough to keep the flower power going.
If you wish to, the common recommendation is a 20-20-20 liquid fertilizer suitable for potted flowers. Follow the instructions on the label. The time to fertilize is before the intense spring and summer growing seasons.
Grow Outdoors Again
You can keep your geraniums growing indoors all year-round or put them outdoors after last frost until early fall (before first frost) each year.
There is always a risk of bringing bugs or diseases back indoors when they return, but they do enjoy life outdoors and it’s fun to keep plants going this way for many years.
If you do wish to give them a summer holiday outside, follow these instructions for hardening off plants. ‘Hardening off’ simply means you gradually get the plants accustomed to outdoor growing conditions so they settle in nicely, avoiding any drastic heat, light, or cold.
Find Your Frost Dates & Hardiness Zone
Average Frost Dates | Use this calculator at Almanac.com. Enter your city and state or province to find your first and last frost dates and number of frost-free days.
Ecoregion | Learn about the native plant and animal species and environmental conditions specific to your region to better understand why your garden choices matter.
Learn More: Understanding Frosts & Freezing For Gardeners
If you’re like me, it becomes a fun challenge to see how many years you can keep the plants going. At some point they may become too big for the house but will have one fabulous final summer on the patio.
How To Bring Plants Indoors For The Winter also has more tips on overwintering various tender plants.
~Melissa the Empress of Dirt ♛
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