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.
When should I start bringing them in and what do I need to do to prepare them for the move? Houseplants/tropicals need to come inside when night temperatures are below the low- to mid-50s or approximately one month before you normally turn on the heat in your house.
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.
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.
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.
Plan to bring in your houseplants when temperatures are forecast below 45 degrees F to protect them from stress and cold damage. Tender perennial herbs like Rosemary or Lemon Verbena can be brought indoors as well for winter cooking.
H2 Rating - 34 to 41° F (1 to 5 C)
Overall, these annuals are the most delicate of all the hardy annuals - one might call them half-hardy since they are really only hardy into the few temperatures just above freezing. And it's important to NOT let them freeze.
ACCLIMATING YOUR PLANTS TO The INDOORS
Avoid moving plants directly from outdoor conditions to the indoors as this can stress them. Instead, gradually acclimate them by placing them in a shaded or partially shaded area for a few days. Don't be alarmed if your plant drops some leaves soon after being brought indoors.
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.
Early Spring - As Soon as the Ground is Workable
If it sticks together the ground is too wet to work. Bareroot perennials, as long as they are dormant, can be planted now. Very cold tolerant annuals such as violas, primroses and pansies can be planted, they must be hardened-off in order to survive.
Covering plant material at temperatures between 39-30 with freeze cloth or covering can be effective. Prolonged exposure at temperatures of 28 degrees and below will notice protection results diminish with each degree dropped.
Depending on the species, temperatures dipping below 45-50°F can cause damage. Here are some things to consider before you bring your houseplants back indoors.
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.
Spray with Insecticidal Soap: Before bringing your plants indoors, thoroughly spray their leaves, stems, and trunks with insecticidal soap to eliminate any remaining pests. Allow the spray to dry thoroughly before bringing the plants inside.
Morning sun is tends to be superior to afternoon sun because it will dry dew from leaves of the plant, which reduces disease, and it is cooler. Most plants, even those that tolerate full sun, will appreciate even momentary respite from the afternoon sun.
Temperature. Mums are some of the most well-known heralds of autumn. These flowers bloom practically everywhere once the summer blossoms start to fade away making them fall favorites. Mums are hardy blossoms that can withstand colder temperatures – down to 20° Fahrenheit – but prefer the 60-70° Fahrenheit range.
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.
There are, of course, many variables that can affect winter hardiness in a plant, but in general, my rule of thumb is as long as the mercury stays in the 20's at night and rises above freezing during the day, our plants should be just fine.
Indeed, a plant that is drought stressed will often show more damage after a light freeze. So if they are dry, always be sure to water your potted plants before a freeze to help them better handle the cold. ANSWER: It depends on how cold it's going to get.
Of course the main benefit of soaking houseplants in soapy water before bringing them back indoors is killing all the bugs, but there are a few other benefits too. This method for debugging and cleaning potted plants is great because now your houseplants will get a good watering before you bring them back indoors!
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).
Saturate the soil with 1/2 cup hydrogen peroxide 3% per 1 litre water. Put wet soil in a watertight container and leave overnight before planting. This kills pathogens such as fungi and bacteria including insect eggs and nematodes (roundworms).
Focus on frost hardy annuals. Some of these annuals that can withstand 20 degrees or so, including pansies, snapdragons, dianthus, alyssum, dusty miller, viola, and osteospermum. Keep in mind that flowers may be a bit ragged after such cold but the plants should make it through ok.
Many newer cultivars are able to withstand hotter temperatures, but no petunias thrive in chilly temperatures. When spring temperatures dip below 40 degrees F, either cover your outdoor petunias with frost cloth or bring them indoors. Temperatures below freezing will kill them in a jiffy.
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.