You can also use insulation materials, greenhouses, heating mats and other simple ideas such as recycling household materials to re-use and save you cash, while your plants thrive. To keep plants warm in winter, insulate them from cold drafts, cover with frost blankets or mulch, and provide extra heat if necessary.
Most houseplants are tropicals and prefer temperatures between 65-75°F during the day and about 10 degrees cooler at night. For many plants, temperatures below 50°F can cause problems.
Putting old blankets or plastic sheets at the coldest point of the night or placing soil mulches on the pot are possible ways to cover your plants. This would trap the heat while protecting them from chilly winds; just make sure to unwrap them during the day.
Light freeze - 29° to 32° Fahrenheit will kill tender plants. Moderate freeze - 25° to 28° Fahrenheit is widely destructive to most vegetation. Severe or hard freeze - 25° Fahrenheit and colder causes heavy damage to most plants.
An important factor in the chance of survival is how long the plants were exposed to cold temperatures. A few hours can do the job, depending on the plant. Generally, though, it takes 12 to 24 hours of exposure to cold temperatures to completely kill most tropical plant species. If you're in doubt, check the roots.
Tips to keep plants warm include insulating your plant pots with bubble wrap and investing in space heaters or heat mats to keep the warmth contained for indoor plants. Unusually, another tip is to make use of the fridge.
A space heater or solar lamps is all you need to keep the garage warm enough for plants to thrive. Keep in mind that the hotter the room is, the more light and water your plants will need. So you only need to keep the room above freezing for your plants to grow.
Heat Mats. While you can use any old heat blanket, you are better off choosing one that is designed to keep your plants warm. That's where a seedling heat mat comes in. That way you can be sure they are getting the right amount of heat.
Leaves Wilt or Droop — As the cell damage occurs, the leaves will lose their rigidity and start to droop or even curl in on themselves. If you have been watering as usual, it is time to consider other causes for your plants' wilting and drooping appearance including cold shock.
According to the Department of Plant and Soil Science at the University of Vermont, most tropical plants will suffer damage if temperatures drop below 40. But there's a little more to it than just toting your green friends indoors.
When nighttime temperatures start to dip consistently to around 50°F, it's time to bring plants back indoors. Most houseplants are native to tropical areas and will not tolerate freezing temperatures.
From that experience, I've found the best frost protection for your outdoor plants is either free or cheap. Cardboard boxes and brown grocery sacks make perfect frost cover and at the end of the season can be recycled. I keep various boxes on the patio and when frost is forecast simply put one over the plant.
I did some research and found out that houseplants need to be taken indoors before overnight temperatures dip below 45 degrees. Most tropical plants suffer harm from temperatures below 40 degrees.
When Should You Cover Plants? Cover your plants at night and remove them during the day when the temperatures rise above 32 degrees F, so that the soil can warm up again.
The general rule of thumb is that most plants freeze when temperatures remain at 28°F for five hours. Of course, there are exceptions to this rule. Seedlings, with their tender new leaves, often give up the ghost when temperatures dip to 32-33°F. Tropical plants have differing low-temperature thresholds.
Bring Inside During Those Cold Nights
Just like you likely can't survive these freezing cold temperatures, neither can your plants. To keep them warm and happy, bring them inside at night. You can place them in your garage or even inside your front door.
It should be noted that some house plants are more vulnerable to cold damage than others and when the thermometer dips – they can suffer. Some of those more sensitive to cold temperatures: Orchids (Phaleanopsis sp.), Mandevilla, Bougainvillea, Oriental Hibiscus, and Poinsettia.
By lowering the temperature in your home while you are away, the plants will use less water. Most plants can tolerate temperatures as low as 50 to 55 degrees for this time.
Both heat mats and heat lamps can be used to provide extra warmth for your plants, but there are a few key differences between them. Heat mats are better for germinating seeds and propagating cuttings.
For humans it affects us, but for plants it can be lethal, because the leaves start to lose more water than they can absorb, dry out and die. For this reason, the closer they are to the heat source, the worse it is for them.
While your first thought might be to just crank the heating up, it might be too warm for your plants. You should try to avoid temperature extremes. For example, don't stand your plants on top of or directly in front of heaters but you should also keep them away from cold draughts from windows or doorways.