Put your plants out only after night temperatures remain above 60°F (usually mid-May or early June). Acclimate plants to increased light by placing them in a shady area outdoors. Slowly introduce indoor plants that like sun into a sunnier location over a period of two weeks.
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.
When do I know it's safe to bring my plant outside? 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.
As many gardeners know, there's a common rule of thumb that advises when it's OK to start planting flowers and vegetables: You should hold off on planting until after Mother's Day.
Most houseplants are native to tropical areas and will not tolerate freezing temperatures. Many indoor plants will see damage when temperatures drop to the mid to lower 40s°F and nearly all will die if exposed to below freezing temperatures.
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.
For most flower types, optimal storage temperatures range between 33°F – 37°F while cold-sensitive blossoms and tropical flowers should be maintained at temperatures above 50°F.
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.
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.
Early morning (5:00 to 9:00 am) is the best time to water the garden when using a sprinkler, garden hose, or any other device that wets the plant foliage. When watering is completed, the plant foliage dries quickly. The rapid drying of plant foliage helps guard against the development of fungal diseases.
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.
Plants need to be transitioned indoors before the outside temperature starts dropping below 45 degrees Fahrenheit (7 degrees Celsius) at night.
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.
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.
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.
When you initially place the plants outside, put them in a partial shade location with only a few hours of morning sun or afternoon sun for the first few days. Gradually increase the amount of direct sunlight they receive by moving the plants into full sun for a limited time, about 4-5 hours.
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).
It depends! You can plant trees, shrubs, perennials, and cool-season annuals, vegetables, and herbs now, as long as the ground is not too wet. But you should typically wait to plant warm-season flowers and vegetable plants until May 1st or Mother's day.
Overall, even flowers can tolerate light freezes (low 30s to upper 20s °F) and even a little snow. Record cold temperatures (below mid to upper 20s) will damage or destroy many of the flowers of early blooming varieties. The foliage of fully emerged spring-flowering bulbs like tulips and daffodils can also be damaged.
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.
When you move them outside, it's important not to move them into too much light. Even the brightest indoor locations are only a fraction of the light intensity compared to any shady spot outside. Houseplants will do best if they "vacation" in a full-shade or part-shade location outdoors.
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.
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.
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.