What Temperatures Can Geraniums Tolerate?

Geraniums are classic flowering plants that brighten gardens, window boxes, and planters with their cheerful blooms. While geraniums thrive in warm weather, these plants originated in South Africa and do not tolerate frost or freezing cold. On the other end of the spectrum, extreme summer heat can also damage geraniums. Read on to learn the ideal temperature range for growing healthy geraniums.

Cold Tolerance

Geraniums perform best with warm daytime temperatures from 70-85°F (21-29°C). Cooler temperatures below 50°F (10°C) can cause stunted growth and smaller blooms. Light frost down to 32°F (0°C) can damage and kill geranium foliage and flowers.

However, established geranium root systems can survive light freezes in the ground or in containers. As long as the soil does not freeze solid, the roots will remain alive and send up new growth when warmer weather returns. Covering plants helps protect them from frosty conditions.

To be safe, geraniums are considered tender annuals in zones 3-8. In zones 9-11, they may survive winters outdoors if protected from hard freezes. Most gardeners treat them as annuals and replant each year from cuttings or new nursery plants.

##Ideal Winter Conditions

While geraniums can tolerate some cool conditions. they grow best through the winter with night temperatures around

50° to 60°F (10° to 16°C) – Optimal for steady growth
40° to 50°F (4° to 10°C) – Slow growth, but plant remains healthy
32° to 40°F (0° to 4°C) – Plant goes dormant but roots survive

Avoid allowing geranium soil and roots to freeze solid, Indoor conditions around 50-60°F are perfect for overwintering geraniums

Protecting Geraniums from Frost

To help geraniums survive cool fall nights and frosty conditions:

Move containers close to warm house walls
Cover plants overnight with garden fabric, cardboard, or buckets

Place in a sheltered spot protected from wind
Temporarily bring indoors or under overhangs during cold snaps
Ensure soil moisture is on the dry side before cold nights

Heat Tolerance

Just as geraniums dislike freezing temperatures, they also struggle in extreme summer heat, especially combined with strong sun. Ideal daytime temperatures for geraniums are 70-85°F (21-29°C). They can tolerate short periods of heat up to 100°F (38°C) if soil moisture is adequate.

However, prolonged exposure to temperatures over 90°F (32°C) can cause damage:

Wilting, drying, and scorching of leaves
Failure of flower buds to open or blossoms dropping prematurely

Slowed growth
Leaves turning yellow and dropping

Coping with Summer Heat

To help geraniums deal with heat waves and hot sun:

Provide afternoon shade if possible
Mist plants daily to increase humidity around leaves

Ensure soil stays evenly moist but not waterlogged
Use drip irrigation to avoid wetting foliage
Apply mulch around plants to retain soil moisture

Move containers to shaded areas during the hottest part of the day

##Ideal Growing Temperatures

Geraniums thrive best with average temperatures around:

Days: 70-85°F (21-29°C)

Nights: above 50°F (10°C)

While geraniums can briefly handle temperatures from the 30s to 100°F, extreme or prolonged freezing or heat will damage the plants. Take steps to protect your geraniums from frost and heat to help them flourish within their ideal temperature range. With proper care, they will reward you with vigorous growth and abundant cheery blooms throughout the seasons!

70 degrees and filtered sun WHOOPEE! watch me grow

For the most part, members of the geranium family are happiest in this environment and grow like weeds. Obviously, there are some varieties that prefer other conditions and will tolerate cold and heat to considerable extremes. Some Hardy Geraniums, for example, are cold hardy to 20 degrees or lower while those same plants can withstand full sun in the central valleys and temperatures ranging upward to 100 to 110 degrees.

As a general rule, a canopy of shade cloth securely hung over the top can give the right amount of sun, and temperature becomes the only enemy. That’s why greenhouses and air-conditioners were invented. The rule is, don’t put a geranium in a location where you would not be comfortable yourself. You can find a lot of information that says “Grow in full sun” in books, nurseries, and magazines. But those were written from places with mild climates, not the Central Valleys and foothills of California.

Geraniums are just like people

They don’t like too much heat and sun combined and they don ’t care to sit outside on a frosty morning. They all have a different tolerance for sun and temperature extremes just as we do.

Plants should be grown in containers so that they can be moved to places with better microclimates.

I’m going to move my plants around until I see that each type has found a decent spot. It can be hard to find the right spot in your yard or greenhouse because each type can handle sun and temperature differently.

Don’t forget to protect your plants from the frost. When I know there will be a hard frost, I bring mine inside and let them watch The Garden Channel on TV. They like that.

Can geraniums tolerate a light frost?

FAQ

Can geraniums survive in 40 degree weather?

A: Geraniums come from tropical climes. You could leave them out for the winter if you lived in Los Angeles. But they blacken and die immediately when we get hard freezes, even though they can handle weather down into the 40s.

At what temperature should geraniums be brought inside?

At what temperature should geraniums be brought inside? Once nightly temperatures fall below around 55 degrees Fahrenheit, it’s time to bring your geraniums inside if you plan to overwinter them indoors. If they’re exposed to frost, it might already be too late to overwinter a healthy plant.

What is the lowest temperature geraniums can stand?

Obviously, there are some varieties that prefer other conditions and will tolerate cold and heat to considerable extremes. Some Hardy Geraniums, for example, are cold hardy to 20 degrees or lower while those same plants can withstand full sun in the central valleys and temperatures ranging upward to 100 to 110 degrees.

When can geraniums in pots go outside?

Cut plants back by about a third and position in a frost-free but bright place. The plants won’t go into complete dormancy so water lightly through the winter. In spring, apply a general liquid feed and increase watering. Plant out only once all danger of frost has passed, usually from late May.

How hot and cold can geraniums withstand?

They may withstand temperatures from 40 to 75°F (or 4 to 24°C). You need to consider the proper temperature range, including the minimum and maximum temperature your geraniums may handle, to keep them safe and healthy. How Hot and Cold Can Geraniums Tolerate? Minimum & Maximum Temperature

What temperature can geraniums grow?

The maximum temperature that geranium may handle is about 90°F, or 32°C. Yet, you should let your trees thrive at a wide range of temp from 60°F to 80°F, or 15-26°C to keep them beautiful and healthy.

Can geraniums survive frost?

While some geraniums withstand cool temperatures, prolonged exposure to 35 degrees, especially with frost, can cause stress and potential damage to these plants. As a gardener, I’ve learned that geraniums are favored for their vivid blooms and hardy nature, often thriving in conditions that other plants might find difficult.

How much sunlight do geraniums need?

Geraniums will require at least 6 hours under direct and ample sunlight daily. However, if your place’s temperature exceeds 90°F, you should plant your tree in partial shade. But when living in an extreme climate, you sometimes have to bring your beloved plant inside and might worry about the indoor temperatures.