When Can Geraniums Go Outside

Because they are not cold hardy below US Department of Agriculture plant hardiness zone 9 (San Diego Geranium Society), zonal, regal, and ivy geraniums (Pelargonium x hortorum, Iowa State University) are planted as annual garden flowers in many parts of the U.S. However, some gardeners in colder climates overwinter geraniums indoors and then replant them outside in the spring. When cared for in this manner, the common Pelargonium geranium varieties can live for many years.

When may I plant geraniums in pots outside?

You should observe fresh growth in your geraniums 7 to 14 days after potting them up. Water sparingly and only when the soil dries out about an inch deep if you want this to succeed. The plants should resemble the one above after 4 to 6 weeks, at which point you can begin to harden them off for transplanting outside.

What degree of outside temperature can geraniums withstand?

Geranium plants cannot be subjected to frosts in order to be permanently evergreen, remaining alive with all of their leaves and stems. Frost on the leaves will kill them and make the leaves fall off. The stem will also die back if the frost gets into the tissues on it. Repeated frosts or extended exposure to below-freezing temperatures are not harmful, according to gardeners, unless the cold freezes the plant’s fleshy underground roots and its crown at the soil’s surface. When air temperatures dip and stay between 25 and 28 degrees Fahrenheit, plants can suffer significant damage or even die.

Can I plant geraniums outside yet?

If you don’t have an indoor room, cover the tray with horticultural fleece and leave it in a protected area of the garden. When your geraniums first arrive, place the tray in a frost-free, light, draught-free environment. Water gently by misting or by standing in a shallow tray of water.

Give the plants 24 hours to relax. If the leaves appear a little yellow or if some compost has separated from the root blocks, don’t be concerned.

Large-sized geraniums can be planted right away as long as the risk of frost has gone, while medium-sized geraniums should be nurtured on for 24 weeks before planting.

Be sure to water your plants well.
Push the individual cells up from bottom and out of the tray with your finger or a pencil. Grasp one of the leaves and carefully pull yourself up. Avoid attempting to grip the stem since doing so will seriously harm the plant.
Create a tiny hole in each 9 cm pot of compost and fill it with the cell (one plant per pot). Make sure the joint where the stem and leaves meet is above the surface of the earth, then gently press the plant into the ground.
After transplanting, give the plant a gentle watering and place it somewhere warm and out of direct sunshine.
After a week, feed with a liquid feed and maintain well-hydrated.
They should be prepared for planting after 24 weeks if you maintain the complete stem exposed and the plug submerged so the top of the plug is level with the soil surface. You can plant them in beds, borders, hanging baskets, or planters. After planting, liberally water the area.
After planting, if there is even a little chance of frost, cover with fleece for the night to prevent the leaves from turning brown.

When can I grow geraniums outside of the UK?

In the summer, give geraniums plenty of water and deadhead to promote a second rush of blooms.

Annual geraniums are frequently grown, and at the conclusion of the summer, they are composted. Keeping them over the winter is worth considering if you have space and a spot that doesn’t get frosty.

Lift plants that are in garden soil or big pots and place them in a smaller container to overwinter geraniums. Ideally, you should do this before the first frost. Damaged leaves and wilted blooms should be removed. Plants should be pruned back by about a third and placed in a bright, frost-free area. Because the plants won’t completely hibernate, water sparingly all winter long. Apply a general liquid feed in the spring and increase watering. Plant just until all threat of frost has passed, typically starting in late May.

Geraniums can continue to bloom throughout the fall or even into the winter if grown as indoor plants. Indoor geraniums should not be placed near open flames or radiators.

Here, Monty Don demonstrates how to give wintering geraniums a new lease of life by severely pruning them before they begin to grow:

How to propagate geraniums

In the spring, trim fresh growth from plants that overwintered. If you’d like, cuttings can be taken in the late summer.

Cut above the third joint below the developing tip to eliminate cutting material. Pinch out any buds that are producing flowers. Remove all leaves except for the top two with a clean knife. Recut the cutting’s base at the lowest joint.

Compost that has been cut up should be placed in a plastic garden container and compacted. Water the cuttings, then place them about one centimeter into the compost. Place the pots in a well-lit area that is warm but not hot. If you’ve obtained cuttings from many different types, remember to name the pot.

In our No Fuss Guide, Rosie Yeomans demonstrates how to propagate pelargoniums.

Growing geraniums: problem solving

Pelargonium rust can harm zonal geraniums. This is a fungal disease that frequently gets worse in humid summers or after plants have been grown in an area with inadequate ventilation. Brown patches on the underside of leaves are a sure sign of rust. Plants with brown patches should be destroyed.

In this Quick Tips video, we explain if you should water geraniums over the winter:

How much British cold can geraniums stand?

Geraniums can be preserved for the winter and grown again in the spring in a variety of ways by gardeners. Knowing that I might not be able to find examples quite like them at plant nurseries the following spring, I like to keep exceptionally lovely ones.

Some gardeners overwinter the plants and take rooted cuttings to prolong their longevity so they can be saved as family heirlooms.

With regard to these plants, there is some name ambiguity. Geranium (430 species), Pelargonium (280 species), and Erodium are all members of the plant family Geraniaceae (80 species).

Although we frequently call Pelargoniums (Pelargonium x hortorum) “geraniums,” the term actually refers to a different genus in the same family. I’m combining the two terms in this sentence.

A lot of pelargoniums develop into bush-like plants with thick, succulent stems, making them suitable for winter storage.

Despite being marketed as annuals, they are actually sensitive perennials that can withstand temperatures as low as 45°F (7C). Their ideal growing environment is between 55 and 65 degrees Fahrenheit (12 and 18 degrees Celsius).

Does frost damage geraniums?

Grow geraniums as indoor houseplants or annuals outside their hardiness area. Geraniums can endure cooler temperatures and even light frosts, but when temperatures dip below 20 degrees Fahrenheit, they are subject to harsh lethal freezes, which can cause freeze damage and even lead to plant death. The minimum temperature for geraniums in Celsius is -7 degrees.

What degree of cold can geraniums withstand?

Gardeners have traditionally favored geraniums. They smell wonderful, are colorful, and are simple to grow. How to cultivate geraniums in your house and garden is provided here!

(Note: This page is about Pelargonium plants, sometimes known as geraniums or storksbills. This is not a page about “hardy geraniums, also referred to as cranesbills.

Geraniums are normally kept indoors to overwinter, even if they may be kept outside throughout the warmer months of the year. In contrast, if given enough light, they can bloom all year long indoors.

Geranium or Pelargonium? A Case of Mistaken Identity

Early in the 18th century, Dutch traders who were traveling through South Africa brought the plants that we now refer to as “geraniums” to Europe. Botanists misclassified these new plants into the same genus because they resembled the hardy wild geraniums that are already present throughout Europe.

Botanist Carl Linnaeus of Sweden included them in the genus Geranium in 1753. Pelargonium, which refers to the long, sharply pointed shape of their seedpod, was used to reclassify these new “geraniums when it was later revealed that they differed from European geraniums in the shape of their petals, the number of stamens, and other features.

However, people still refer to them by their old common name, “geranium,” even if we really mean “pelargonium.”

You can grow geraniums as annual blooms or as indoor plants. They can be kept outside in a sunny area throughout the warmer months of the year (between your local frost dates).
If keeping geraniums as indoor plants, make sure to do so in the late summer or early fall when overnight lows begin to consistently fall below 55F. (13C).
Pay great attention to the size and color of geraniums when purchasing them. Healthy stems and leaves will not be straggly or discolored on top of them or underneath them. A plant with evident insect indications should also be avoided. Mealybugs, whiteflies, and spider mites are typical indoor plant pests.
To prevent root rot, put plants in containers with drainage holes.
When planting in pots, use a well-draining potting mixture rather than heavy, clayey soil. Geraniums dislike being planted in mucky, compacted soil.
Place the plants where they will receive 4-6 hours of sunlight per day for the best bloom.

How to Care for Geraniums

After letting the soil somewhat dry between waterings, water it again well.
Water plants significantly less throughout the winter, but make sure the roots are not completely dried up. Given a time of hibernation throughout the winter, when they consume less water and don’t grow as much, geraniums thrive. For additional overwintering tips, see the section below.
Regularly deadhead spent flowers to promote blooming.
Pinch back the stems to encourage bushiness and prevent legginess.
Fertilize approximately every two weeks throughout the active growing months. Half-strength a fertilizer that is water soluble When the plant should be dormant in the winter, avoid fertilizing.
Repotting geraniums can be done in the spring to promote new growth or if they appear to need revitalization.

Overwintering Geraniums

If they receive plenty of sunlight, geraniums that have spent the summer outdoors can be kept indoors. The sun may not be strong enough in northern regions in late winter to promote buds on some cultivars.
Lift the plants before the first fall frost (you can find your local frost dates here), and use a sharp, clean knife to shapely prune the stems back to about 6 to 8 inches. In the low-sunlight environment they are about to enter, they shouldn’t have to maintain substantial amounts of leaves. A simple technique to increase the number of your plants is to save a few stems for rooting.
Place the “mother plant” in the smallest pot you can find—just big enough to hold the roots—and fill it with ordinary potting soil.
The plants should be kept in the shadow for a week before being moved to a sunny location and kept cool.
Geraniums thrive in temperatures between 50 and 60 degrees Fahrenheit (10 and 16 degrees Celsius) at night during the winter, but they can also withstand lows of 32 degrees Fahrenheit (0 degrees Celsius) and highs of 80 degrees Fahrenheit (27 degrees Celsius), provided they are kept relatively dry.
Cut off all the old leaves when the spring growth begins.

Keeping the new growth alive is the only challenge that can compare to getting it to appear. Here is some assistance with that:

Only offer tiny quantities of water when the leaves begin to droop. Don’t feed or fertilize the plants. These plants must have some downtime.
Pinch back your overwintered geraniums in February if you want them to bloom by Memorial Day. Take the plants outside and move them to beds or pots, as you like, once warm weather returns and all threat of frost has passed.
Containers are ideal for growing the Common or Zonal Geraniums (Pelargonium x hortorum) (as well as outdoors).
Hanging baskets, window boxes, and containers are all extremely popular places to use Ivy-Leaf Geraniums (Pelargonium peltatum).

How to Root Stem Cuttings

The majority of geraniums readily take root from stem cuttings when placed in soil, sand, water, perlite, or another rooting medium.

Make a slanted incision 4 inches below the tip of the stem, above the node where the leaves emerge, with a clean, sharp knife. Cut the grass immediately below a node. Remove all except two or three leaves, any buds, and the stipules that resemble leaves at the base of leaf stalks.
To ensure that the cut end of the stem will seal and not rot, roll the stem cutting in newspaper or place it in the shade for 24 hours.
Place the stem in a wet rooting media container and keep it there for two days in a warm, shaded area. Give the cutting indirect sun after that. Just as needed, moisten the medium.
Apply crushed geranium leaves to small cuts to halt the bleeding.
Scarlet geranium is the flower that speaks of foolishness. More floral meanings can be found here.
You won’t have to worry about those bothersome bugs because geraniums are known to be harmful to Japanese beetles.
Keep geraniums out of the reach of curious youngsters and animals (cats, dogs) as they might cause indigestion or vomiting.

Low light, overexposure, and underwatering are common issues. Yellowing leaves are a sign that you are watering your plants either too little or too much. Try to water the geraniums evenly in this situation, and transfer them to a more sunny location.

Should I put my geraniums inside at what temperature?

Geraniums do best in climates between 65 and 70 degrees Fahrenheit during the day and 55 degrees Fahrenheit at night. Horticulturists at the University of California claim that scented geraniums only require four hours of sunlight each day. Install a fluorescent light a few inches above the plants if you are unable to provide them with this. When you bring your potted plants inside after it gets below 45 degrees Fahrenheit, the sudden warmth may shock them, turning their leaves yellow and making them fall. Bring the plant indoors for a while before it becomes cold outside, ideally at night, to prevent this. Each day, gradually lengthen the time. This will ease the plant’s transition and minimize major stress. Give the plant more care and ensure that it receives the right amount of water, light exposure, and trimming until it recovers if it still exhibits indications of shock.

Geraniums should be brought inside when?

Bring geraniums indoors before the first frost to overwinter them. Drag the entire pot indoors where they should stay for a few weeks while you take care of other more urgent garden tasks if you are growing them in a tub or container and have limited time (as it generally is in the fall). If they were grown in beds, simply remove them with a little dirt, place them in a pot, and water them sparingly. They will survive for a few weeks until you can deal with them.