Many indoor plants originate from the world’s tropical regions and are not cold-hardy. An overnight (and unexpected) cold snap can damage the plants you have so lovingly nurtured. But is it possible for your indoor plant to recover from cold shock?
Most indoor plants can recover from cold shock. However, the cold exposure should not have been longer than 24 hours, and you need to provide them with warmth. Move the plants to a warmer place, but do not fertilize them or prune the dead and withering parts unless these look mushy or emit a foul odor.
You don’t have to do too much to revive a cold-damaged indoor plant because plants heal naturally. In this article, I will explain how you can revive an indoor plant that has suffered a cold shock, the symptoms of cold damage in plants, and how you can prevent your plant babies from getting too cold in the first place.
- Symptoms of Cold Shock: Look for drooping, curled, or discolored leaves, damaged branches, a loose root ball, and mushy roots. Also, check for soft or blackened leaves and damage to flowers.
- Recovery: Most indoor plants can recover from cold shock if the exposure was less than 24 hours.
- Immediate Actions: Immediately move plants to a warmer spot and avoid fertilizing or pruning them.
- Natural Healing Process: Plants naturally heal, so minimal intervention is typically more beneficial.
- Root Inspection: Examine the roots for the extent of cold damage, which can indicate the plant’s likelihood of recovery.
- Gentle Care: Provide moderate watering and avoid exposing the plant to sudden temperature changes.
Understanding Cold Shock in Indoor Plants
Daytime temperatures less than 65-75 °F (18.3-23.9 °C) and nighttime temperatures less than 55-65 °F (12.8-18.3 °C) are too cold for indoor plants. Most indoor plants originate in the tropical regions of the world. They cannot tolerate temperatures less than 50 °F (10°C) and can go into shock.
Indoor plants can get too cold if placed in an unheated room (during winter), near exterior windows that tend to frost over at night, or in a drafty corridor.
Identifying Cold Damage in Plants
As a plant parent, you should be able to recognize the signs of a cold shock that your ferns and hoyas exhibit when they are stressed.
Plant cells and tissues contain water. When the temperatures are freezing, the water inside the cells freezes. This damages the cells, and the plant suffers.
Cold damage in plants looks like drooping, curled, or discolored leaves, damaged branches, and a loose root ball. The damaged plant has soft or blackened leaves, or there may be red, yellow, or white marks near the veins of the leaves. Small branches can droop, and woody stems and trunks can split.
The flowers on severely damaged plants can show burn-like marks. Severely damaged leaves and flowers eventually die and fall off the plant.
The chances of a cold-damaged plant surviving depend on the duration of the cold exposure. Usually, 12 to 24 hours of exposure to freezing temperatures can kill most tropical houseplants. However, many plants are more resilient than they appear.
Check the roots of the plant that has been exposed to cold. They will indicate how severe the cold damage is.
Below are the signs to look out for:
- If the root ball is loose and moves without resistance when you move the plant, it is a sign of severe cold damage.
- If the roots are firm and white, you can be sure that the plant will bounce back from the shock.
- If the roots appear mushy and black, the plant will not survive.
- If the roots are somewhere in between, you can give a shot at reviving the plant.
Reviving Plants from Cold Shock
You can revive a plant from cold shock by moving it to a warmer spot near a source of heat. Allowing the plant to rest and keeping it stress-free by avoiding fertilizing, pruning, or overwatering will also help boost its recovery.
Keep reading as I explain what you should do to revive a plant from cold shock.
Move the Plant to a Warmer Spot
If you spot signs of cold shock, you should immediately move the plant to a warmer place.
The plant’s natural healing process will start soon after it receives warmth. Take care that you don’t place the plant where it may be exposed to drafts.
However, do not try to speed up the healing process by providing intense supplemental heat to the plant. For instance, do not place it on top of a radiator or a heating mat. The sudden, substantial change in temperature can stress the plant even more.
Let the plant slowly acclimatize to its new environment.
You can place it on top of the freezer or the oven. These appliances radiate slight warmth when they operate. This heat is gentle and won’t stress your plant.
Do Not Over-Prune the Plant
You might want to prune the dead and withering parts of the plant. However, pruning can sometimes stress the plant even more and delay recovery.
Besides, the dead and damaged parts can insulate the plant and prevent further damage from the cold.
If you want to prune, keep the following in mind:
- Remove dead leaves and prune damaged stems and branches when there is no threat of cold.
- Prune leaves, stems, and branches if they appear mushy, moldy, or emitting a foul odor.
- Do not prune live, green parts of the plants. Gently scrape a stem or a branch to see if green tissues are visible under the outer layer. The presence of green tissue indicates this area of the plant is alive and will heal naturally.
- Wait for new growth to appear before pruning. I suggest you hold off pruning till new growth appears on the plant. You can thus be sure about where the dead and unproductive parts of the plant are.
Do Not Fertilize the Plant
Fertilizing will trigger the plant to put out new growth instead of using its energy to heal and recover from the cold shock. Let the plant rest, and do not hamper its natural healing process.
If you must fertilize your indoor plant, wait until the plant has fully recovered from the effects of cold shock. This should take anywhere from a couple of days to even weeks, depending on the type of plant and extent of damage caused.
Gently Water the Plant
Cold-damaged plants are dehydrated because the soil freezes and water is not available to the plants. Keeping them hydrated will nourish them and give them the energy to recover.
Water the plant right after you move it to a warmer spot. Continue watering till water runs out from the bottom of the container.
Keep the plant hydrated. Gently water it till the threat of cold has passed.
However, do not overwater the plant. Giving it too much water can trigger a vigorous growth spurt that can weaken the plant.
Also, a stressed-out plant has a limited capacity to take up water from the soil. Overwatering can make the soil soggy and promote the breeding of fungi and mold.
It may take several weeks or months for plants to recover from cold shock and show new growth. New leaves emerge when the damaged leaves fall off the plant, but they may not do so immediately. You must continue providing the plants with adequate warmth, water, and light during this period.
Preventing Plants From Getting Too Cold or Freezing
If you live in an area where the winters are brutal, it is always prudent to adopt preventive measures to ensure your indoor plants do not get too cold to the extent of freezing.
You can prevent your plants from getting too cold by covering the plants and the containers with an insulating material before the first frost hits your area. Place the plants in a warm room that receives ample sunlight but is sheltered from drafts. Mulch the soil to prevent it from freezing.
Read on as I explain how you can protect indoor plants from cold.
Cover the Plants and the Containers
You can cover your plants with fleece or bubble wrap. You can also put small plants inside a cloche at night.
Plants in containers are more vulnerable to root freezes. Protect their roots by covering the containers with bubble wrap.
Place Them in a Sunny and Sheltered Room
Place your indoor plants in a sunny and sheltered room where they will receive plenty of sunshine without being ripped by frosty winds.
Below are some ideas on where to place your indoor plants to keep them warm and prevent cold shock:
- Place them against a south or west-facing room wall. The walls of these rooms absorb heat during the day and radiate it out at night.
- Keep your plants away from external doors and windows that can let in cold drafts.
- Place the containers on the radiator, the freezer, or the oven. These appliances emit heat when they operate and will keep the plants warm.
- Place the containers on heat mats or electric propagators. The plants will receive heat from below, so their roots will not freeze.
- Place the plants in a room with a programmable radiator. A programmable radiator is energy-efficient and keeps your indoor plants warm in winter without increasing your energy bills.
Mulch the Soil
Mulch the soil in the containers with dry material, such as wood chips, shredded bark, or straw. Mulching prevents the soil from freezing and protects the roots from cold shock. It’s advisable to add as much mulch as possible if living in extremely cold climates.
Indoor plants add pops of color, dollops of drama, and an aura of liveliness in the depths of winter. Keep them blooming and thriving by protecting them from cold shock.
Here are a few takeaways:
- Keep tabs on the weather and be aware of the first frost date in your area.
- Adopt pre-emptive measures to prevent cold exposure in your plants.
- Inspect them daily to check for signs of cold damage.
- Move them immediately to a warmer spot if you notice symptoms of cold shock.
- Cut back on the TLC; don’t overwater or over-prune.
If you found this guide helpful, I recommend my complete guide on caring for houseplants. I’ll discuss the many tips and tricks for keeping your plants happy and healthy: How To Care for Houseplants (The Ultimate Guide)