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.
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.
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.
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.
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.
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.
It's best to wait until the last freeze of the season has passed before planting anything outside. Typically for the DMV the last freeze of the season occurs between the last week in March and the first week in April. A good rule of thumb is to wait until Mother's Day to plant anything outdoors.
Many tropical plants cannot survive temperatures below 40 degrees. If you cannot move your pots (with annual or perennial plants), or you have tender plants in the ground, cover your plants. The idea behind covering plants is to trap the heat from the soil and keep the cold air out.
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.
Know the difference between cotyledons and leaves.
They're thicker and harder than true leaves, which will grow later and resemble the foliage of a mature plant. You'll want to wait until you have at least 3 or 4 true leaves before you consider transplanting.
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.
The best time to water outdoor plants is in the morning when temperatures are usually cooler. This gives the plants time to absorb the water so they can get through a long, hot day. The second-best time is late in the afternoon or early in the evening. Try not to water at night.
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.
The best time to plant trees, flowers, or any plant is during the dormant season. In North America, this is usually late fall through early spring. While it's okay to plant during the rest of the year, it will require more maintenance from you in the form of watering, fertilizers, etc.
For most regions, April is the month during which the threat of frost has passed, and soil temperatures are consistently warm enough to plant a wide array of plants, from fruit and vegetable seeds to bare-root perennials, summer-blooming annuals, flowering shrubs, and flowering vines.
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.
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.
High temperatures mean a high potential for water to evaporate before it ever reaches the roots. Avoid sprinklers and instead use spot watering at the base of the plant, soaker hoses, or drip irrigation systems to provide water efficiently. Plants in containers and hanging baskets may need water twice a day.
Generally, most plants can be safely placed outdoors once the threat of frost has passed and temperatures consistently remain above freezing. For many common garden plants, this usually means waiting until nighttime temperatures consistently stay above 50°F (10°C) before moving them outdoors.
If you're looking for tips for protecting your plants from frost, avoid using garbage bags as plant covers. Trash bags are not the best protection against frost damage, primarily due to their material. Most garbage bags are made out of low-density polyethylene plastic.
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.