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Some plants tolerate frost and cold temperatures better than others. Plants always killed by frost include summer annual flowers and summer vegetables like impatiens, marigolds, coleus, tomatoes and peppers. Subtropical and Tropical plants are the most sensitive to frost (citrus, hibiscus and bougainvillea).
Most plants prefer a temperature of no less than 60° F, though many can tolerate as low as 40° F. Along with this, while the improper temperature can certainly be an issue, fluctuations in temperature are the true killer. Learn the ideal temperatures for your green friends so they can be healthier and happier.
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.
If it stays cold for more than one night, can I keep my plants covered, or should I remove the coverings at some point? A. Our recommendation would be to remove the cold protection covering once temperatures are above 32 degrees.
If you're wondering at what temperature threshold you should be bringing your plants, there's a short answer: when nighttime temperatures reach 45 degrees (F), it's time to bring your plants indoors.
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. Some keel over when temps fall to 40°F; others crumble at 35°F. Other plants are just hardy by nature and can withstand temperatures as low as 18-20°F.
As gardeners, our frost dates are based on 32 degrees Fahrenheit (0 degrees Celsius) to avoid the risk of any plant death. However, know that even if air temperatures are as high as 38°F, frosts may occur on the ground and on plants. It's better to protect plants just in case!
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.
WHEN TO BRING PLANTS INSIDE. As a general rule, tender plants should be brought in when nighttime temperatures are below 50 to 55 degrees F, even if they are hardy for your zone. A plant's roots are more exposed when planted in a container versus in the ground.
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. Adjust thermostats to cater to your comfort, but remember your plants need some consideration.
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. Some outdoor plants won't survive the harsh conditions of winter, bring them inside and use these tips for caring for them through winter.
The snowdrop flower. As a plant that actually despises warm winters, the snowdrop flower performs its best in frigid temperatures. This flower can withstand temperatures down to -30 F. while still displaying its bright green stems and delicate, white flowers.
Colder weather can decrease plant enzyme activity. This then disrupts plant nutrient intake because plants secrete enzymes to digest surrounding materials for soil. Consequently, this can stunt growth or more severely cause them to die.
Colder temperatures (26-31 degrees F.) may burn foliage but will not kill broccoli, cabbage, cauliflower, chard, lettuce, mustard, onion, radish, and turnip. The real cold weather champs are beets, Brussels sprouts, carrots, collards, kale, parsley, and spinach.
It's important to pay attention to the temperature dropping when the sun goes down. Once temperatures are consistently between 60 and 45 degrees Fahrenheit, it's a good idea to start bringing your plants inside at night. However, you can keep them out during the daylight hours if the temperature stays above 45 degrees.
Hardy cool-season crops (cabbage, broccoli, onions, radish, spinach, turnips, peas, and radish) grow in 40 degree daytime temperatures and can handle some frosty nights without protection.
When should I wrap my plants for winter? This Old House landscape contractor Roger Cook suggests to start wrapping your plants in November. If your plants are new, be sure to cover them for the first two years. The older your plants get, the sturdier they become in surviving winters.
A covered porch usually provides protection from light frost, but the garage or sun room is better for freezing temperatures. A couple days in darkness won't hurt the plant. Or move them out during the day and back in at night, if cold temperatures persist.
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.
Should I cover my plants at 36 degrees? As a whole, all tender plants should be brought indoors or protected with garden fabric to prevent frost when it is 36°F outside. For cold-hardy plants, this is entirely optional. But it's better to err on the side of caution when the temperature falls below 40°F.
Perennials. The newly emerged growth of most perennials can tolerate temperatures in the low 30s and upper 20s °F. This includes many early emerging perennials such as bleeding heart, daylily, catmint, and columbine. In most cases, early leaf growth on these plants will be just fine with cold temperatures.