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.
Geraniums can withstand a frost.
Knowing how to overwinter geraniums is very useful for gardeners since it can help them save money and extend the life of particular varieties they enjoy.
Pelargoniums, sometimes known as geraniums, are mainstays of the summer garden. Geraniums are ideal for adding cheer and long-lasting color to hanging baskets, containers, and borders since they come in a variety of colors and flower continually as long as they are deadheaded.
However, when making your job list, you might consider including them as one of your winter garden ideas.
When growing frost-sensitive plants, planning a winter garden is crucial. Geraniums are perennial plants that put on a long display, but they are frost tender, which means they won’t survive harsh winters. If you are interested in cultivating geraniums, you must learn how to overwinter them.
Geraniums are South African natives that thrive in the heat and can withstand periods of drought with little water.
Pelargoniums, sometimes known as geraniums, may live in USDA zones 7 to temperatures of -12oF (0oC) if they are sheltered. They are hardy in climates between 20oF and 50oF in zones 9 through 12. They need to be sheltered in these conditions because, while they can withstand brief frosts (temperatures slightly below freezing), they cannot withstand prolonged exposure.
The Pelargonium genus contains a wide range of cultivars, all of which are categorized as delicate perennials. According to David Taylor, vice chairman of the UK Pelargonium and Geranium Society, “this means that they are not cold hardy as the majority of the founding species come from the warmer climbs of the Southern Hemisphere.
Perennial plants are able to flourish for a number of years, however in the UK this would mean that they would also need to be sheltered from winter wet and damp in addition to frost.
Geraniums can be cared for like annuals by being dug out in the fall, composted, and then replaced with fresh plants the following year. The appropriate care and attention, however, will enable you to winterize geraniums, keeping them alive throughout the winter so they can bloom once more the following year.
According to David Taylor, vice chairman of the UK Pelargonium and Geranium Society, “Keen enthusiasts keep their pelargoniums in growth during the winter and continue to feed and water but a few key points can be undertaken by anyone to keep your pelargoniums (geraniums) alive throughout the winter” (opens in new tab).
Pelargoniums are known as geraniums, but these plants are not the same as hardy geraniums or cranesbill, which are a different kind of plant and don’t need to be overwintered.
Should I protect my geraniums from frost?
According to the University of California, outdoor geraniums should be kept frequently watered, especially if they are in pots, to help protect them from an unusual cold snap. In comparison to dry ground, which will instead rob moisture from the roots, weakening the plant, moist soil that freezes causes less damage to plant roots.
To shield geraniums from the cold before light frosts, cover them with “tents fashioned from newspaper, cardboard, a bed sheet, or burlap. Avoid letting the cover touch the plant itself because this will allow the geranium to become frosted. Place mobile geranium containers in safe settings, like next to house walls, which are typically several degrees warmer.
Do geraniums recover from a frost?
- Make sure you thoroughly inspect your geranium plants before bringing them inside for the winter. Look for symptoms of pests and illnesses like rust and remove any dead leaves or wilting blossoms. Only zonal pelargoniums are impacted by this, but it is becoming more widespread. It arrived in the nation for the first time in 1968, and it does best in the moist summer or fall months. Fortunately, it doesn’t seem to spread to the plants quickly and is simple to treat, so merely plucking the afflicted leaves is an effective management. You might also consider using the fungicide Dithane 945 as a spray.
- Placing your overwintering plants somewhere bright and sunny will help them retain their need for light throughout the winter. Your plants will receive 50% less light if they are placed more than three feet from a window!
- Because your plants continue to thrive throughout the winter, keep the roots moist. While geraniums frequently survive droughts, they rarely flourish. Show plant growers take special care to keep the roots of their plants damp but never soggy during the winter.
- Ventilate as frequently as you can to maintain a dry environment surrounding your plants. Your plants will turn into a moldy, rotting heap if you don’t allow the air to circulate. The greatest electric fan heaters are those that operate automatically since they circulate air while simultaneously raising air temperature.
- Geraniums are fairly inexpensive to overwinter in the greenhouse because they only need to be kept frost-free. To keep temperatures above freezing, however, we do advise utilizing a heater. Set the thermostat on your heater to 5C, which is 41F. The plant will not survive if the stems become frosty! The winter months are a great time to store your delicate pelargoniums in porches, sunrooms, or conservatories.
We hope that we have provided you with enough of tips so that you can continue to enjoy your geraniums year after year. Visit our geraniums hub page, which is brimming with useful resources, for additional details on how to cultivate and take care of these well-liked plants. And do get in touch with us through our social media outlets to share your personal favorites; we’d love to hear from you.
What degree of cold can a geranium 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.
What degree of indoor temperature is appropriate for geraniums?
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?
Your geraniums should be potted six to eight weeks before the final average frost date in your region. Clean up the plants by removing any extra-long roots and trimming the stems back to healthy green growth, as shown in the inset. Take the geraniums out of the bag or box they have been sitting in for the past several months. By the time it was cleaned up, this one was only a little over 4 inches long.
Then, put potting soil in a container that has already been wet, and tuck the stem down so that two leaf nodes are below the soil—this is where new roots will grow.
How can I prevent frost damage to my plants?
Planting too early might result in a crisis if a cold snap is impending, whether it was because you were seduced by some striking hue at the garden center or simply wanted to start the gardening season early. It’s not difficult to help your seedlings survive the great frost, but it does take some planning.
When temperatures drop, you can usually rely on improvised protection for plants. The necessary tools must be prepared in advance to protect plants from frigid mornings for larger plantings, such as a food garden.
Knowing when prized vegetation starts to turn frost-burned brown will help you know what to do when freeze warnings are in effect. As a general rule, plants typically freeze when the temperature stays at 28°F for five hours.
There are, of course, exceptions to this rule. When temps drop to 32–33F, seedlings often die because of their delicate new leaves. There are many low-temperature thresholds for tropical plants. Some collapse at temperatures below 40°F, while others break down at 35°F. Other plants are naturally resistant and can endure temperatures as low as 18 to 20 degrees Fahrenheit. Do a search in gardening books and internet resources to discover the threshold for your plants.
Take it up
Moving plants away from potential danger is the simplest cold-protection strategy. Potted plants and seedlings in flats both benefit from this. Moving plants onto a porch with a roof, into a garage or shed, or under a deck frequently provides sufficient shelter.
Rely on Water
Just before sunset, water the soil to raise the temperature of the surrounding air overnight as the water evaporates. Water-filled buckets or gallon jugs should be left in the sun all day. Move them close to threatened plants at night. Air temperatures will be moderated by the water, and if it freezes, heat will be released. To boost midday heating, paint a few water-holding containers black for best results.
the air flowing
The biggest harm is done to plants by cold, motionless air. To prevent frost from accumulating on plants, you can use an electric fan all night to create a breeze. Never forget to keep electrical connections dry.
Plants Should Be CoveredPlants should be covered with sheets, towels, blankets, cardboard, or a tarp to protect them from everything but the harshest freezing (28F for five hours). Inverting baskets, coolers, or any other container with a firm bottom over plants is also an option. Before it gets dark, cover plants to keep warm air in. Coverings shouldn’t ideally contact the foliage. If windy conditions are anticipated, anchor cloth coverings.
When the temperature rises and the frost has melted in the morning, remove coverings. Under dense covers, heat from the sun can accumulate and cause plant death.
Blankets that collapse
Row covers, or gardening blankets, should always be accessible. These covers are created in various thicknesses from plastic or synthetic fibers. Lay row covers directly on the plants, or suspend them over a bed with pegs to form a tunnel.
Activate lights
An incandescent light bulb produces enough heat to raise the temperature of the air around it just enough to keep a plant from freezing. For this method to operate, bulbs must be close to plants (within a distance of 2-3 feet). (Fluorescent bulbs can’t produce enough heat to complete this task.)
Defend specific plants
Set up hot caps
At planting time, stiff plastic containers with venting holes are placed over the individual seedlings. Hot caps function similarly to cloches (small greenhouses), but the daily task of applying and removing the covering is eliminated by venting holes. Use plastic two-liter bottles or gallon jugs with the bottoms cut off and the lids removed to simulate a hot cap (but saved). In the evenings when the weather turns chilly, replace the lids.
A Wall O’Water tepee, which encircles individual plants with a sleeve of water-filled tubes, is a variation on the hot cap concept. During the day, the water absorbs the heat of the sun. The water gently freezes at night, releasing the sun’s stored radiant heat and preventing the air within the tepee from becoming frosty.