Your indoor container plants can suffer from cold soil if positioned close to windows or exterior walls during the winter or placed beneath cool air vents during the summer. Keeping your indoor plants at the correct temperature is essential, which begs the question: How can you keep soil warm while it’s indoors?
You can keep soil warm while indoors by utilizing these 10 tips:
- Place your potted plants near sunny windows.
- Position containers near warm air vents.
- Situate potted plants near space heaters.
- Bundle containers in a thick fabric.
- Secure an electric blanket around plant containers.
- Put potted plants near fireplaces or stoves.
- Invest in an indoor greenhouse.
- Keep container plants away from exterior walls and windows.
- Use indoor lights to keep plants warm and healthy.
- Water plants with warm water.
Indoor plants bring life and color into your home, and there is no need to let them suffer during the chilly months. In this guide, we will explore some tips for helping you keep indoor plants warm and healthy, even when the weather outdoors is frigid.
1. Place Your Potted Plants Near Sunny Windows
If your indoor plants suffer from cold soil during the spring or summer, the culprit might be your home’s air conditioning. Fixing this issue is often as simple as relocating your plants to sunny windows, where they can receive plenty of warm sunlight.
Remember, plants need sunlight for photosynthesis (the process that gives plants energy). But sunlight also transmits energy in the form of heat, making it a natural and straightforward way to keep potting soil warm indoors.
Naturally, you’ll want to ensure you’re placing plants near windows that aren’t near air vents, as the cool air flowing from AC vents can keep the soil relatively cool, even with the addition of sunlight.
The only exception to this rule is warming soil when the weather outside is cold. In this instance, placing your indoor plants near windows can negatively affect soil temperature.
So if the weather is cold and snowy, you’ll likely want to avoid placing them near frost-covered windows, opting instead to place them near warm air vents.
2. Position Containers Near Warm Air Vents
If the weather outside is cold, you may want to move your plants away from windows and position them beneath or near air vents. Warm air blowing out of these vents not only keeps your indoor areas comfortable but can also keep soil from freezing.
If your home has floor vents, you’ll want to ensure you’re placing your plants at least 12 inches (30.5cm) away from vents to prevent blocking their airflow. But if you’re working with ceiling vents, you can safely position your indoor plants directly beneath them to keep the soil warm.
Still, only about 75% of homes in the US have central air. But if your home does not have a central air conditioning and heating unit, you can keep your indoor plants’ soil warm by placing the containers around a toasty space heater.
3. Situate Potted Plants Near Space Heaters
Space heaters aren’t the most energy-efficient way to keep a home warm, but they are helpful for those heating older homes without furnaces, boilers, or central heating. These devices could also help you warm indoor potting soil during cold weather.
You can even invest in a tiny space heater just for your indoor plants, helping reduce wasted heat and electricity while reducing the risk of overheating your soil.
To use this device to keep potting soil warm, simply:
- Position your potted plants in a circle around the space heater (leaving 12 inches between the plants and the heater), and
- Adjust the temperature to the desired level.
After that, you should check every few hours to ensure your potting soil is warm but not overheated. You could also select a compact space heater with a built-in timer for greater peace of mind and ease of use.
Of course, space heaters can consume a ton of electricity. If you’re hoping to reduce your energy use while keeping indoor plants warm, you might want to opt for insulating fabrics instead.
4. Bundle Containers in a Thick Fabric
When it’s cold outside, you likely wear a thick sweater and coat before heading outdoors. After all, thick, insulating fabrics can help you stay warm in cold weather. The same principle applies to potting soil, even when it’s indoors.
Felt fabrics are some of the best options, as felt is a natural insulator, helping to trap warm air while blocking cool air from passing through. But felt might be the best option, as it’s readily available from most craft stores, affordable, and capable of absorbing spilled water.
5. Secure an Electric Blanket Around Plant Containers
An electric blanket can help warm your bed during frigid winter nights. But it can also keep potting soil warm indoors!
There are two ways to use electric blankets to keep your plants’ potting soil warm. The first method is:
- Wrap the electric blanket around the outside of the container.
- Secure the covering with an elastic cord.
- Plug the electric blanket into an outlet.
- Set the heating level of the blanket.
- Set the blanket timer.
This option is best for larger potted plants. But if you’re looking to keep several smaller container plants warm, you could opt for the second method:
- Spread the electric blanket across the floor.
- Place your small potted plants onto the blanket.
- Plug the blanket into an outlet.
- Set the heating level and timer.
Because hot air rises, placing a heating blanket beneath container plants could be an excellent way to warm potting soil. This warm air emitted from the blanket will rise upward through the soil, ensuring that every inch of soil is adequately heated.
Risks of Using an Electric Blanket
You shouldn’t place heavy or oversized containers on an electric blanket. These can crush the heating elements inside the blanket, increasing the risk of electrical fire or blanket malfunction.
It’s also crucial to choose an electric blanket with a timer, as leaving an electric blanket unattended for several hours can result in overheated soil.
6. Put Potted Plants Near Fireplaces or Stoves
If you have a fireplace or stove in your home, you can use these appliances to help keep your plants’ potting soil warm.
The only caveat is that you’ll want to ensure you’re not placing your plants too close to a fireplace or stove, as the heat emitted from these appliances can dry out the soil or your potted plants.
A great way to select the best spot is to:
- Stand several feet away from your lit fireplace or wood-burning stove.
- If you feel a little chilly, take a small step closer.
- Continue until you feel warm (but not hot).
- Mark the spot with masking tape or painter’s tape.
- Place your indoor plant on the marked site.
If you don’t have a space heater, fireplace, or stove, you may want to consider investing in an indoor greenhouse. These devices can trap heat, and they can also trap moisture, making them a top-notch choice for indoor plants that prefer high-moisture environments.
7. Invest in an Indoor Greenhouse
If the above tips aren’t helping keep the soil warm (or drying out your plants), you may consider purchasing an indoor greenhouse.
Indoor greenhouses vary significantly, from tabletop models capable of accommodating containers with a 4-inch (10.2cm) diameter to large floor models capable of accommodating planters up to 12 inches (30.5cm) wide.
While indoor greenhouses aren’t always the most affordable solution to cold potting soil, they are an effective way to trap heat and moisture, helping your potting soil remain warm and preventing it from drying out.
Some indoor greenhouses also have built-in lights, helping your potted plants enjoy simulated sunlight and increased warmth!
8. Keep Container Plants Away From Exterior Walls and Windows
While this tip conflicts with our first suggestion, keeping indoor plants away from windows and exterior walls (those closest to the outdoors) may be a great way to keep the soil warm during winter.
Even the best-insulated walls can become cold during heavy snowfall or frigid winters; the same is true of windows. Windows are often the least-insulated part of a home, allowing cold air to move inside during winter and cold air out during the summer.
Besides, windows may not be the best source of light during the winter, when sunny days are rare and days are short—placing your potted plants in central rooms (with no walls directly facing the outside) is a fantastic way to keep potting soil warm.
Though you might be concerned that your plants won’t get enough sunlight if moved away from windows, it’s crucial to remember that indoor lights can substitute daylight during the winter.
9. Using Indoor Lights To Keep Plants Warm and Healthy
While your living room floor lamp might not be the ideal substitution for sunlight, several types of indoor lights mimic sunlight and help keep potting soil warm. Investing in these lights is an excellent way to keep indoor plants healthy when the weather is cold and overcast.
10. Water Plants With Warm Water
You can also keep the soil warm by pouring warm (but not hot) water onto it! Filling your watering can or spray bottle with water that’s between 68℉ and 89℉ (20℃ and 31.6℃) is an excellent way to add a little warmth to cool soil.
How To Test Water Temperature
To ensure you’re using the ideal temperature water, you can use a standard food thermometer or an infrared thermometer. Otherwise, judge by hand; the water should be room temperature and not hot to the touch.
That said, an infrared thermometer might be the better option, as it allows you to gauge temperatures from a distance.
You can even use an infrared thermometer to test the temperature of your soil!
To use this thermometer to test water or soil temperature, you only need to:
- Turn it on by pressing the ‘Power’ button on the front of the gun.
- Get close to the object you want to gauge (within 12in or 30.5cm).
- Aim the thermometer at the water or soil.
- Press the trigger.
- Read the backlit display.
Warm Water Alone May Not Be Enough
As the water drains from the top of the soil to the bottom of the container, it will spread a little warmth to plant roots, helping them absorb water more readily. However, this warm water can lose its heat quickly when poured onto cold soil.
Consequently, it’s best to pair this method with at least one other existing warming method. Doing so can help slow the cooling of the water as it moves through the soil, preventing the moisture from freezing and causing damage to plant roots.
When soil is cold, roots struggle to take in water, leading to diminished plant health and premature death.
Fortunately, you can keep your indoor plants’ soil warm by following these steps:
- Put your plants near a sunny window.
- Place plants near warm air vents.
- Situate plants near space heaters.
- Bundle indoor planters with thick fabrics.
- Place a heating pad around potted plants.
- Put indoor plants near lit fireplaces.
- Invest in an indoor greenhouse.
- Keep plants away from windows and exterior walls.
- Use indoor lights.
- Water plants with warm water.