Grown under the marginal conditions of most homes and apartments, houseplants can become tired-looking during the winter months. You can renew your plants by moving them outdoors during the summer. Put your plants out only after night temperatures remain above 60°F (usually mid-May or early June).
Time It Right. While it might be tempting to ship indoor plants outside at the first sign of spring, it's best to wait until nighttime temperatures stay at or above 60°F, and after any threat of frost has passed. If you're planning ahead, use the average last frost date for your area as your guide.
It's safe to move your plants outside when the outdoor temperatures stay consistently above 50°F. Pay attention to the weather report. If nighttime temperatures are set to fall below 50°F, bring your plants in for the night. Bring them back outside when temperatures rise.
Each plant has a different threshold when it comes to dealing with the cold. Some plants can survive outside even when temperatures hit freezing. Others need to be brought indoors when temperatures reach the mid-40s. Be sure you know this before you plant.
First, your plants should not be moved outside until nighttime temperatures are staying above 50 unless you are moving them back in at night, which is fine. Houseplants are subtropical and tropical plants and aren't happy in temperatures below 50 and are definitely cranky below 40.
The hardiest of flowers can be planted as soon as the soil in your garden can be worked, even if it's several weeks before the last frost of the season. For half-hardy flowers, hold off until a couple weeks before the final frost, and for tender flowers, plant when there's no chance of frost for the rest of the season.
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.
So, yes, it's been cold at night around Southern California, but folks, 45 degrees is a still a long way from the freezing temps that can burn our tender tropicals and other plants, like a multiday cold snap in 2007 that severely damaged crops in Central and Southern California.
Cacti and Succulents
It shouldn't come as a surprise that succulents and cacti will thrive outdoors. These plants prefer bright light and to dry out in between waterings, but just because they are desert plants, don't just move them into the brightest spot outside one day and assume they'll fend for themselves.
First, it's good to know which plants are sensitive to temps around 35 or 40 degrees F. These are common tender plants that will need some protection. Hanging baskets: begonias, calibrachoa, gerbera, impatiens, vinca, euphorbia, and scoparia.
Moving houseplants outside is a big change in environmental conditions, so acclimating them is important. Never move houseplants from indoors into full sun. Leaf burn, discoloration, and drop can occur. On some species, especially succulents, the damage to the fleshy stems and leaves is permanent.
Know The Limits
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.
Most flowers should be planted after your region's last frost date. Planting flowers in spring is the most popular time, but perennials do fine if planted in early fall in the North and late fall in the South.
The general answer is around 90 degrees F, with some exceptions to the rule. This means that when temps rise above 90 and remain there for a lengthy spell: Leaves wilt. Water evaporates into the atmosphere more quickly in high heat, draining a plant's reserves.
In spring, apply a general liquid feed and increase watering. Plant out only once all danger of frost has passed, usually from late May. If growing geraniums as house plants, you can let the plant carry on flowering into autumn, even winter. Keep indoor geraniums away from radiators or open fires.
Grown under the marginal conditions of most homes and apartments, houseplants can become tired-looking during the winter months. You can renew your plants by moving them outdoors during the summer. Put your plants out only after night temperatures remain above 60°F (usually mid-May or early June).
Chives, sedum, geraniums, herbs, and agave can withstand a variety of extreme temperatures and still thrive. What are some low-maintenance outdoor potted plants that are hard to kill? Herbs like sage, rosemary, and thyme are great plants that require little maintenance and continue to grow despite neglect.
Low Temperatures
Wait until the temperature is consistently above 65 degrees Fahrenheit (18 degrees Celsius) before moving houseplants outside. If temperatures dip below, bring your plants back inside.
The trick is to make sure you protect these cold sensitive plants before they succumb to a killing frost or freezing temperatures. All tropicals can take the heat but most are highly sensitive to cold weather. For the most tender plants, temperatures in the 40's can do them in.
So will peppers survive 40 degrees? To sum it up, most peppers won't necessarily DIE from 40˚ F temperatures, but their growth can be stunted, and they may be slow to recover so it's best to keep them warm if possible.
There is no universal temperature for all plants that is too cold, so that is why it is important to do your research. However, it is safe to say if living in an environment with harsh winters and temperatures below 20°F, it is always wise to bring plants indoors during this time, if possible.
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.
On a cellular level, this means that as the water turns to ice, it expands, rupturing the cell wall. This is permanent damage, but it doesn't mean the plant will die. If the damage is isolated to a portion of the plant, it can be revived and recover.