Marijuana plants function the best when their surroundings maintain a consistent temperature between 70 and 75 degrees Fahrenheit during the daytime, and 50 and 60 degrees Fahrenheit at night. This ideal temperature can sometimes vary, however, such as when growers add carbon dioxide to their plants, then the best temperature is right below 85 degrees Fahrenheit.
- Cold Problems
- How To Fix Cold Problems
- Heat Problems
- How To Fix Heat Problems
- Ideal Temperature For Marijuana Plants
- Temperature’s effect on plants
- The ideal temperature for marijuana per grow stage
- Creating the perfect environment
- Temperature and humidity
- Measuring temperature
- Maintaining correct temperatures
- Correcting temperature problems
- Frequently asked questions
- Effects Of Cold In Plants: Why And How Plants Are Affected By Cold
- Why Does Cold Affect Plants?
- Plant Growth and Temperatures
- Protecting Plants from Cold Damage
- How does cold weather affect your health?
- At risk: Immune system
- At risk: Heart
- At risk: Balance
- At risk: Skin
- At risk: Body temperature
- Why Does Being Cold Affect Our Productivity In The Workplace?
- The Effects Of Chilliness In The Workplace
- Why Are We So Susceptible To Cold?
- How does cold weather affect seniors?
- How do cold temperatures affect plants?
- How to Spot Cold Weather Damage on Your Plants
- Are your outside plants looking a little sad?
- What Happens to Plant Life During the Winter?
- Winter Water Loss
- Water Transport
- Tree Shape
- Extreme Cold
Anything below 60 degrees Fahrenheit is going to cause problems for your marijuana plants – especially if it continues too long and if it’s during the plant’s flowering phase. This can cause problems with your resulting harvest, so it’s important to pay close attention to the temperature surrounding your plants.
With outdoors growing, you should know that they most likely will experience a night or two of as low as 50-degree temperatures. Do not fear: this should not cause long term problems for your plant and its harvest. Marijuana plants are impressively robust, but of course it is still a good idea to keep the environment within the ideal temperature range whenever possible. That being said, if the temperature gets lower than 40 degrees Fahrenheit, there will be trouble for your plant.
Make sure to download my free marijuana grow bible at this link here for more growing tips.
Cold temperatures generally cause things to slow down. Your marijuana plants won’t produce yields that are as high as normal due to the delayed growth, although you may not recognize this if it is your first season with this particular plant.
How To Fix Cold Problems
When dealing with too much cold, there are some specific steps you can take to deal with its effects on marijuana plants. These methods can vary for indoor and outdoor growing areas. If you are an outdoor grower, you could give a gas patio heater a try. This is especially useful for the night when temperatures are even colder. You should aim for a consistent temperature of 60 degrees, so get as close to that as you can. Another option for outdoor growers is to cover them to provide insulation – try one made out of polyethylene plastic. If you grow in containers you can place them inside during rea.ly cold nights.
If you are growing indoors, try a CO2 generator or electric heater to help balance things out. For big indoor setups, go for a hot water heater that recirculates the water throughout the garden. And make sure to download my free marijuana grow bible at this link here for more growing tips.
The cold is not the only thing that might have adverse effects on your marijuana plants – the heat can be just as troublesome. Plants that are overheating will show the earliest signs in their leaves with curling or burnt appearances.
Your plants should not have too much trouble with random bouts of heat if they are mature and have developed sizable root systems, therefore allowing them to take in more water despite the heat. If temperatures are somewhere between 80 and 90 degrees and your plants are in their vegetative state, however, you might see the development of stems that are longer and leaner than normal. Read more about the perfect temperature in the article ‘What Is The Ideal Temperature For Growing Marijuana Plants?’
If you are growing your plants indoors and the grow lights are causing the temperature to be too high, then during the flowering phase, buds that are highest (or closest to the light) will be bleached and stretched out. Your plants will have burnt tips as well, but the problem with the buds is the best way to see that it’s an issue with excess heat, not light. Other signs include yellowing, brown spots, and curling leaves. Plants that aren’t receiving enough water have a higher chance of succumbing to heat stress. More tips in my free grow bible at this link here.
How To Fix Heat Problems
To keep things cool indoors, you can install a ventilation fan as well as air conditioning, or else air or water-cooled lights to ensure a lower temperature despite the light intensity. Only focus on the heat that is touching your plants, since that is the only thing that will have an effect on your plants. Exhaust fans work well to dump the heat from your garden outside – just be sure to use a carbon scrubber to make sure the smell of your garden is not launched outside with the hot air.
One simple way to fix the problem is to move the light further away from the plants. Loon-watt lights are supposed to be three feet away from your plant, air-cooled lights should be between 18 and 24 inches from your plants, and water-cooled lights can be the closest: within a foot away from your plants. If you are growing outdoors and there is a heat spell, there are a number of ways to go about cooling down your marijuana plants. For instance, micro-sprayers are a good way to have significant reductions in heat – they could lower the temperature on your plants by as much as 30 degrees Fahrenheit.
If your plants are growing in containers, heat will have a more devastating effect on them. Try moving the plants out of direct sunlight to help combat excessive heat; otherwise, put them into a lighter-colored container instead because it will reflect sunlight.
To prevent heat stress from the beginning, shift your watering times to before and after the hottest part of the day – early morning and late evening, for example. This will allow your plants to absorb the water without it evaporating quickly. If need be, you can cover up your garden with a sheet in order to provide them with shade – but don’t make this a long term change, or else it will cause them to go into shock from the sun when the cover is removed.
For marijuana plants healing from heat stress, try using seaweed kelp extract to ensure that they do return to their former strength. It also serves as a preventative measure and will help keep your plants from getting heat stress again in the future.
The following symptoms might be displayed if your plant has heat stress:
Burnt or brown leaf edges
New, higher growth affected
Curling leaf edges
Wilting and drooping leaves
Wilting and drooping of the whole plant
Ideal Temperature For Marijuana Plants
Ensuring your plants have the perfect temperature is not the easiest thing to do. Some would say it is as much art as it is science.
That doesn’t mean you can’t figure it out, though. You just need to learn a few things first; which I will teach you in this article.
I’ll explain why temperature involves more than degrees, and why it is even more complicated when growing indoors. I’ll also show you how to recognize temperature related problems and make adjustments in your grow room.
Keep reading to learn everything about temperature while growing marijuana or skip ahead to your favorite section
Temperature’s effect on plants
Plants are fairly self-sufficient, but when it comes to temperature they are at a disadvantage. Even though it is vital to their health, plants can’t create their own heat. Unlike animals and humans, a marijuana plant is entirely dependent on its environment.
How does a plant get warm?
A plant’s temperature develops from a combination of external light, external temperature, and the amount of evaporation. A plant’s exact temperature is not something you can read on a thermometer, but it is a definite measure of health.
Marijuana plants won’t usually die from being too hot, but their growth can slow from it. High external temperatures (above 80 degrees) while flowering will not only slow down bud growth but also reduce their smell and potency. If you care about growing buds with plenty of cannabinoids, you need to be sure the external temperature is kept under control during the flowering stage.
The quality of your buds is reason enough to care about temperature, but there are many more.
You also should care about their health.
Be sure to check my free Grow Bible for more tips on controling your grow environment
In general, too much heat causes plants stress.
If your plant gets too warm, photosynthesis is impacted, enzymes activity decreases, and fewer proteins are produced. Some proteins even break down. If this continues long enough, your plant can die.
Below are some ways temperature impacts the marijuana growing process.
My selection of indoor seeds are perfect for growing in a controlled environment. Although some work fine when grown outside as well, these are the seeds you need if you’re growing indoors.
Most of us understand how plants make sugar right?
Well, one example of how temperature can affect the overall health of your plants is the process of photosynthesis. To a certain degree, photosynthesis is not affected by temperature – it can safely occur at 60ºF (15ºC) or 85ºF (30ºC). Regardless of the temperature, your plant will still be able to produce enough sugar.
Temperature becomes a factor when your plant needs to send those sugars to the places they’re needed. Sugar doesn’t move as well when it’s less than 68ºF (20ºC). In fact, the sugars will get stuck, and your plant will suffer.
In other words, make sure the plant is warm enough to function.
When this happens in mature plants and only lasts a few days, it’s not that big of a problem. Once the temperature is resolved, the backed-up sugars will go where they should be. However, in immature plants, this situation will stunt the plant’s growth.
Another temperature- sensitive function is respiration. Respiration decreases as the temperature drops. This should be a good thing because it lowers the amount of energy a plant uses. However, it also creates a dangerous crutch.
Here’s why that’s a problem:
When a heavier crop develops because of a lowered temperature, total crop respiration increases. Now, when the temperature increases, more energy is needed to keep the plant alive.
That leads to an even bigger problem:
The extra energy requirement leaves little left over for growth.
In my Grow Bible you can learn more about the plant’s biological processes
Heat also causes other problems for cannabis. When it is too hot, your plant is more likely to suffer from:
- spider mites
- root rot
- white powdery milder
- nutrient burn
- increased stretching.
These situations are even more likely if it is also humid, or if there is increased water transpiration.
The ideal temperature for marijuana per grow stage
Your marijuana plant will respond to temperature changes differently based on their growing stage. As a grower, you need to make sure your plants have the best temperature for the growing stage they are in. Below are some ideal temperatures for every stage of the growing process.
Seedlings and clones
Clones do not have their root system yet, so they depend on transpiration for their water. Therefore, they require high amounts of humidity, at least until they have fully formed roots. Many growers use a humidity dome to create an ideal amount of humidity for clones.
Clones like a high humidity
The ideal temperature for clones is between 68-77°F (20-25°C) with high humidity. At these temperatures, they should quickly form roots and become more self-sufficient. These temperatures are similar for seedlings.
During the vegetative stage, young plants prefer a high humidity (70% or more) and temperatures between 68-77°F (20-25°C). However, as the plant gets older, a slightly lower humidity is okay. This is more of an issue for indoor grown plants, as outdoor grown plants are able to withstand more temperature fluctuations.
The ideal temperature during the vegetative stage is between 68-77°F (20-25°C) with moderate humidity while also providing slightly cooler temperatures during dark periods.
The cooler ‘night’ periods are perfect for encouraging growth. Don’t let temperatures drop below 59ºF (15ºC). Once the plant matures, it should be able to withstand cooler temperatures during the day and drier air as well.
I always get strong genetics in my seed store to ensure survivability of the plants
White Widow has been developed through the years and is a very , very sturdy plant. Learn more about this classic strain.
Once your plant reaches the flowering stage, it can thrive at a comfortable room temperate with low humidity. Unless you are adding additional CO2 to your grow room, a temperature under 82°F (28°C) is ideal. These lower temperatures encourage potent, trichome rich buds that you can smell and enjoy before you burn them.
Don’t go over 82°F (28°C) because higher temperatures cause terpenes to evaporate and they also slow bud growth. If your buds are too hot during this time, you may be literally burning away the good stuff as they grow, leaving very little taste or smell by the time of harvest.
Be especially careful to keep it comfortable for your plant after week 6 or 7. This is when terpene production is at its max, and you risk evaporating them due to high heat.
For optimal trichome production, make sure it is slightly cooler during the dark periods. The change in temperature may trigger increased terpene content as it optimizes plant processes. Just don’t make it too cold.
This process leads to what is commonly known as the dew point. The dew point occurs when the air can no longer hold any more water vapor, and it condenses into droplets called dew.
Create the ideal temperature during flowering stage
If you aren’t familiar with terpenes, they involve much more than taste and smell. They also impact the color of both the buds and the entire plant. Terpenes are responsible for the tomatoes red color, and they possibly may do something similar in certain cannabis strains. With the proper dark-period temperatures, you can bring out interesting colors in your plants (such as blue, pink and purple).
This phenomenon depends on the strain, of course. Most marijuana plants only grow green buds, but if you want to see what your plant can do, keep it cool for it ‘night’ temperatures and find out.
Drying and curing
Harvesting is not the last step to top-quality bud. Even with the best genetics, you’ll need to properly dry and cure your buds. Perhaps half of what determines great marijuana is how it has been dried or cured.
Professional dried and cured marijuana is more potent, looks better and produces a smoother smoke.
It will have that ‘sticky-icky’ feeling that marijuana lovers crave.
Maintain the right temperature and humidity while drying
If you want the best results from your harvest, focus on maintaining the correct temperature and humidity throughout the entire process. This will help prevent mold and over-drying as well as make it easier to produce the best weed possible.
One thing people always ask me is when they should harvest their plants. This free Harvesting ebook gives a perfect idea of when to cut your plants.
Keep temperatures around 64°F (18°C) and the humidity at 45%. The values in the picture above are not correct. I made these pictures just after harvesting, so temperature and humidity were still high.
Create a smooth airflow bud don’t blow directly on your buds. This will cause them to dry too quickly.
Creating the perfect environment
Whether you are growing indoors or outdoors, you need to be concerned about your plant’s environment. Try and create a temperature that is ideal so that they can thrive.
With outdoor growing, keeping your plants warm can often be a problem. The good news is that most outdoor varieties can endure temperatures as low as 50°F (10°C) without any problem. That being said, fifty degrees is still not an ideal temperature because it tends to slow down tissue growth and photosynthesis later in the day.
Anything below 40°F (4°C) can result in damage to the tissue.
Results of the wrong temperature
- Curled – too hot
- Small plants – too cold
- Burned – too close to bulb
There are ways to keep your plant warms outdoors. Try:
- Gas patio heaters
- Polyethylene plastic covering
Both options can keep gardens warm on frigid nights. The covering also protects plants from other dangerous weather elements. The idea is to maintain a temperature of at least 60 degrees to promote plant growth.
Indoor growing temperatures are directly controlled by the grower, leaving as much room for error as there is for success. All you must do is make sure your grow room maintains the correct temperature.
Here’s the problem:
The ideal temperature in your grow room depends on several factors. The location of your room in the building is an important one for example. A basement grow room is a lot cooler than in an attic with a flat roof.
Aside from that, the size of your room, the airflow, the number of lights and the extraction rates play an important role. Keep this in mind when building your grow room.
“Install a maximum / minimum thermometer and hygrometer in all grow rooms.” ~ Jorge Cervantes
Temperature between 68ºF and 77ºF for cuttings and seedlings
When the light is turned on, an ideal temperature for the cuttings and seedlings is between 68ºF and 77ºF (20ºC and 25ºC). As the plants get older, they can evaporate a little bit more, and the temperature may increase to a maximum of 82ºF (28ºC).
When the lights are off, the temperature should lie between 59ºF and 72ºF (15ºC and 22ºC). Another important rule is that the temperature differences between day and night cannot be too high, a maximum difference of 18ºF (10ºC). So, when it’s 82ºF (28ºC) during the day, it cannot go below 64ºF (18ºF) at night.
In general, marijuana grown indoors functions best at moderate temperatures between 68 and 77°F (20-25°C) during the light period and a drop of no more than 18°F (10°C) to 60°F (15°C) during the dark period. CO2-enriched plants will produce more at a marginally higher temperature of just under 82°F (28°C).
If the floor can have a steady temperature at around 80°F (27°C), the roots will be warmed, and the stems and leaves will withstand influxes of colder air. A heating mat is ideal if you’ve only got a few plants to worry about.
Larger gardens might require the use of a recirculating hot water heater to ensure optimal temperatures.
Here’s my selection of indoor seeds which all thrive when grown in a controlled environment.
Bruce Banner is not just a guy that turns into a big green monster… It packs quite the punch as a marijuana strain as well! Be sure to check out Bruce Banner by ILGM!
Temperature and humidity
In a grow room, you need to think about humidity as well.
First, here’s a bit of information on how humidity works. The air our plants ‘breathe’ contains water vapor. The amount of water vapor in the air can vary. This is the humidity.
In a grow room, the humidity is always a bit higher because the plant’s leaves evaporate water. Marijuana plants only use 10% of the water they absorb for growing and evaporate the other 90%.
However, the air can only hold a certain amount as well. When this number is reached, condensation begins. You’ll notice condensation as little droplets of water in the colder areas of your grow room or on your plant.
Temperature plays a huge role in humidity because it affects the amount of water vapor that the air can hold. Warm air can handle much more water vapor than cold air.
Humidity while growing
How do you know you are getting close to having too much moisture?
Here’s what experts do:
You measure the relative humidity.
The relative humidity (RH) is a measurement of the percentage of moisture already in the air. For example, an RH reading of 70% indicates that more water vapor can be absorbed into the air. However, 70% at 77 degrees is different than 70% at 68 degrees, because warmer air can hold more moisture.
Specifically, at the higher temperature, 2 pounds of air could have as much as .45 ounces of water vapor in it. On the other hand, 2 pounds of 68-degree air only holds .32 ounces. So, if you allow the air to cool down, the air can hold less water vapor, leading to condensation while also raising the relative humidity.
Example: 77 Degree air cooled to 73 degrees – RH rise from 70% to 80%
This process leads to what is commonly known as the dew point. The dew point occurs when the air can no longer hold any more water vapor, and it condenses into droplets called dew.
Dew point is important because:
It helps you find the ideal temperature for your grow room.
In the example above, we know that the dew point of 77 degrees with 70% RH is 66 degrees. Therefore, we must keep the temperature above 66 degrees to prevent excessive moisture.
Ideal humidity for marijuana seedlings
Maintaining proper moisture in your grow room is important because the moisture levels can frequently change.
A properly ventilated grow room always experiences regular drops in temperature. The heat from the lamps as well as the naturally humid air is regularly sucked out through fans and other ventilation methods, changing the moisture levels. Even though it regularly changes, you must make sure the humidity levels are optimal for your plants.
Outdoors it’s easy to measure temperature. Indoors isn’t that difficult either.
First, you should measure the temperature in your marijuana grow room with a thermometer. There are analog and digital thermometers, and they’re for sale everywhere for a few bucks. I always use a digital thermo/hygrometer (something like this one) with built-in memory so I can see what the maximum and minimum temperature was.
It’s also a good idea to get one with a temperature sensor on a wire, so you can hang the display outside your grow room, and can see the temperature when the lights are off.
Measuring temperature and humidity
Here are some tips for getting a good temperature reading:
- Always measure the temperature in the shade
- Measure at various places in your growing room.
- Provide good air flow by placing several fans. Lamps emit radiant heat; however, it does not affect the air temperature.
It will always be a few degrees warmer right under the lamp than in a shaded spot.
The amount of temperature change that comes from lamps isn’t really an issue; just make sure there’s enough distance between the lamp and the plant.
Do not misunderstand this, however, as radiant heat does affect the leaf temperature. Therefore, you do not want the lamps to be too close to the plants as this could cause heat stress.
In my free Grow Bible you will find more information on proper measuring and grow room control.
Maintaining correct temperatures
Maintaining the perfect temperature for your plants can be tricky, but it is not impossible. When growing indoors, you can control the environment. Outdoor growing is a little less certain.
Temperature is important for the photosynthesis of your marijuana plants; low temperatures reduce evaporation through the leaves. This causes a suction force, which takes up nutrients via the roots, to become smaller.
What happens next is:
The nutrients that are necessary, but aren’t absorbed, remain in the growing medium and eventually disintegrates in the root environment. High acidity in the growing medium reduces the working of the roots which makes the plant absorbs less water and nutrient, and……
Growth comes to a halt.
This is why maintaining the correct temperatures is crucial to the health of your plants.
In a grow room, if the temperature drops below 60°F (15°C) during the dark period, plants will grow more slowly, and yields will not be as abundant. This won’t be readily apparent if you aren’t particularly familiar with the garden’s normal output.
Grow rooms use lamps, so there’s also the possibility of heat stress. It is caused by the improper placement of lights. In this situation, the leaves don’t actually burn, but they are damaged.
This rarely happens to outdoor grown plants because we are referring to temperatures greater than 105 degrees. However, this can occur in indoor setups if you are not paying attention.
Heat stress on plants – leaves curl up inwards
You’ll recognize heat stress on the top leaves of your plant. They will start to turn yellow and curl inward. This happens as the plant tries to protect itself from the heat. To see it in action, put a lamp too close to your plant. It’s a simple mistake that can quickly cost your plant its life.
What may seem like a small external imperfection at first, can have serious consequences in an entirely different part of the plant. Therefore, it’s essential to create a good climate in your grow room.
Correcting temperature problems
If you’ve already noticed temperature related problems with your plants, it is not too late to save them. Here are three different problems that you may experience in your grow rooms as well as ways to correct them.
Prevent heat stress from happening to your plants by keeping your lamps a bit higher than your plants and/or by using a fan to blow away some of that excessive heat.
If you want something more substantial, try installing air-cooled lights with reflectors that will reduce the heat near the light. Water-cooled lights are actually more effective at diminishing light-generated heat.
Air-cooled lights, a quick fix
For the most part, HPS lights should maintain a distance of around 3 to 4 inches per 100 watts from the tops of the plants. Air-cooled lights make the acceptable distance range between 2 and 3 inches per 100 watts.
Water-cooled lights make the acceptable distance about 2 inches or even less per 100 watts from the plant tops. With light movers, you can move the lights closer or farther away depending on your preference.
Check this table with distances for all grow lights. Including LED and CFL.
Temperatures that are too low
A few nights of cool temperatures won’t significantly damage your crop, but if it continues to occur throughout the flowering period, it can definitely be cause for concern. A CO2 generator or electric heater can heat the room adequately.
CO2 system setup. Over $1000,- investment
When the lights are on, it’s not normally necessary to increase the temperature. The lamps themselves will take care of that. However, it is important to distribute the air over your room evenly so that you’ll get the same temperature everywhere. Use swivel fans for this and aim them between the lamps and the plant.
Increase the temperature while growing by using swivel fans
Fresh air from outside should also be well distributed over the growing area so that there won’t be any cold spots. Especially in winter when the temperature can get below freezing.
When the lights are off, however, it can get cold in your grow room. Luckily there are plenty of things you can do to increase the temperature.
Try these options:
- A simple space heater with a thermostat (keep in mind, they consume a lot of electricity)
- A radiator with a thermostat
- A CO2 generator
You can also turn off the extractor fan (that provides the fresh air) the moment the lamps turn off. This can be done by a so-called fan controller with thermostat, or with a timer.
These strains are perfect if you have to deal with cooler climates. Both outdoors or during your indoor winter grow these strains are sturdy survivors.
Temperatures that are too high
Heat often becomes a problem in a grow room. This has to do with the fact that the lamps produce a lot of heat. Fluorescent lighting is not really a big deal, but HPS lamps can heat up your room to soaring temperatures of 122ºF (50ºC), which is fatal to your marijuana plants.
How do you not burn up your plants?
First of all, the dimension of the room is important. For a 600-watt HPS lamp always use a minimum space of 3 ft x 3 ft x 6.5 ft (100cm x 100cm x 200 cm).
For the extraction, use the following simple formula:
number of watts divided by two = extractor in cubic feet (meters).
Using this formula, 2 x 600watt HPS requires an extractor fan of 22000 cubic ft. (600m3). The extractor fan blows the hot air outside and sucks fresh air inside.
That’s not all you can do, however:
You can put a carbon filter on your extractor, so it doesn’t blow marijuana smelling air out. You can also put ballasts etc. outside your grow room because they generate a lot of heat.
Lower your temperature by using an extractor with a filter
Perhaps the easiest way to keep the temperature low is by running your lights at night. Your lamps will turn on for a few hours after the sun has set and turn off a couple of hours after sunrise. This way you’ll have your lights on at the coolest period of the day.
You can imagine that if it’s hot weather outside, you’ll also suck this hot air into your grow room with your extractor. So, the room temperature never gets below the hot temperature outside. There are also professional growers who use an air conditioning unit so they can run it during the day and at night.
Understanding how to provide the best temperature for your plants is one of the easiest ways to ensure a successful grow. You simply need to learn some best practices, measure regularly and adjust as needed. There are plenty of ways to do this, even if you grow outdoors.
When you focus on providing the perfect temperature, you’ll notice that your plants can thrive.
Give your plants the best start, however, by purchasing seeds from my marijuana seedstore. We ship to the United States, Australia and a number of other countries. If the order doesn’t get to you or the seeds don’t germinate, then you can get new seeds free of charge.
Frequently asked questions
Is it a good idea to grow seedlings outside? Seedlings require a warm environment and high humidity, typically around 80 degrees. Most outside environments cannot reliably provide these temperatures. For more on seedlings read this article.
Can LED lights help reduce the heat in a grow room? LED lights typically use less energy, but they still produce heat. While you can use them for your grow, keep in mind they may not provide the optimal result. Learn more about LEDs in this article.
Can marijuana survive with incorrect temperatures? The numbers in this article are the ideal temperatures for the best results. Some hearty strains, especially those designed for outdoor growing, can grow under more extreme temperatures
How does a heat extractor work? An extractor removes both warm air and CO2 out of your grow room, helping to lower temperatures on your grow room. Use it with fans and cooled lights to create the optimal environment n your grow room.
The founder of I Love Growing Marijuana, Robert Bergman, is a marijuana growing expert that enjoys sharing his knowledge with the world. He combines years of experience, ranging from small-scale grows to massive operations, with a passion for growing. His articles include tutorials on growing…
Effects Of Cold In Plants: Why And How Plants Are Affected By Cold
Not all plants are hardy in cold regions. You can identify if yours are if you know the United States Department of Agriculture zone for each plant. However, even plants in the correct zone may suffer from cold damage. Why does cold affect plants? The reasons for this vary and depend upon site, soil, duration of cold, and other factors. How plants are affected by cold also varies depending upon the type of plant and the above factors.
USDA guidelines for plant hardiness are just that, guidelines. The actual hardiness of a plant will fluctuate according to the microclimate, exposure, water and nutrient intake, and the overall health of a plant. The reasons cold affects plants abound, but we will try to narrow down the most obvious culprits.
Why Does Cold Affect Plants?
All conditions experienced by a plant affect its health and hardiness. A lack of water may cause wilting and sometimes death in plants. Excess or a dearth of nutrients can also contribute to negative plant health. In this way, so too can weather conditions cause damage to plant vitality. Cold freezes the cells in a plant, causing damage
and interrupts the pathways for nutrients and water to flow.
In small branches and twigs, the living xylem is much more affected by cold than the cambium and phloem. This tissue is not dormant and the effects of cold in plants results in blackened stems and tissue death. Desiccation, sunscald, salt damage, heavy snow breakage and numerous other injuries are also how plants are affected by cold.
Plant Growth and Temperatures
The effects of cold in plants are most noticeable in plants that are marginally hardy or those that have not properly hardened off. Cold damage also shows up in early spring when a warm period encouraged new growth, which is particularly susceptible to a sudden freeze. Temperature is a huge factor that breaks dormancy in seeds and plants, starting the growing cycle anew.
While you may have a hardy plant for your zone, conditions such as microclimates can minimize that hardiness. Low areas hold cold pockets that can lower temperatures significantly. These locations also gather moisture which will freeze and cause frost heaves, damaging roots. Plants on higher locations become victim to cold winds and sunscald caused by exposure to winter sun. Often the damage is not noticeable until spring growth returns. For this reason, considering plants’ growth and temperatures they will be encountering is an important factor when locating plants.
Protecting Plants from Cold Damage
Because of the number of reasons cold effects plants, protection must start at planting.
- Choose hardy specimens or even native plants, which adapt best to their climate.
- Locate the plant where it will have some shelter.
- Apply mulch around the base of plants to protect the root zone.
- In areas with unpredictable weather, frost barriers may be useful, placed over trees, shrubs and sensitive plants.
- Any plant that is marginal should be avoided but in instances where you just can’t resist purchasing one, place it in a container and bring it inside a garage or basement until all danger of frost has passed.
Weather can be extremely unpredictable, so be sensible in plant location and choice, and provide sheltered areas for your prized specimens. This will help ensure your plants over winter with minimal harm.
How does cold weather affect your health?
Published: November, 2014
Your immune system, skin, balance, and heart may be at risk.
As temperatures drop in the winter, weather-related health problems start to rise. “The cold weather brings a number of risks, especially for older adults,” says geriatrician Dr. Suzanne Salamon, an instructor at Harvard Medical School. Here are some of the ways you may be vulnerable this winter, and how to fight back.
At risk: Immune system
During winter months, people spend more time inside and in close contact with each other, such as in stores, malls, and restaurants. This means that the flu, coughs, and colds are more easily spread.
What you can do: “Get a flu shot, wash your hands frequently with soap and water or hand sanitizer, and cough and sneeze into the crook of your elbow, not your hands,” says Dr. Salamon.
At risk: Heart
Cold weather acts as a vasoconstrictor, which means it narrows blood vessels. This raises the risk of heart attack.
What you can do: Dress warmly when going out, with a hat, gloves, and a warm coat. Don’t do any strenuous activity outdoors that may stress your heart, such as shoveling snow.
At risk: Balance
Icy sidewalks can make falling easier, putting you at risk for fractures.
What you can do: Avoid slippery surfaces if possible. Wear shoes or boots with heavily textured soles that can grip surfaces. Use handrails, even if you feel you don’t need one.
At risk: Skin
Dry winter air can suck the moisture from your skin.
What you can do: Use a moisturizer with an oil base to block evaporation. Shower in lukewarm—not hot—water. Use a humidifier to replenish moisture to the skin’s top layer.
At risk: Body temperature
Older adults are at risk for hypothermia, in which the body’s internal temperature falls too low. “Even prolonged exposure to mild cold can cause it,” says Dr. Salamon.
What you can do: Bundle up if you’re going outside, and be aware of signs that your body isn’t handling the cold well, such as stiffness in the neck, arms, and legs. Call 911 if you suspect you or someone you know is suffering from hypothermia.
As a service to our readers, Harvard Health Publishing provides access to our library of archived content. Please note the date of last review on all articles. No content on this site, regardless of date, should ever be used as a substitute for direct medical advice from your doctor or other qualified clinician.
Why Does Being Cold Affect Our Productivity In The Workplace?
We’ve talked a bit before about the effects of temperature on workplace productivity in the workplace. It’s just one of the many reasons why you should keep a careful eye on the heating, cooling and ventilation systems in your offices – and if they’re showing signs of not working properly, don’t hesitate to book a service and maintenance as a matter of priority! But, you may be thinking, surely a bit of chill doesn’t make that much of a difference? Well, have we got some news for you…!
The Effects Of Chilliness In The Workplace
In many ways, British employment law is a bit fuzzy on temperature. Technically, there’s no legal minimum temperature, but employers have a duty “to provide a reasonable temperature in the workplace”, which is generally considered to be at least 16oC. Over the years, there have been numerous scientific studies demonstrating the effects of coldness in office environments.
One such study showed that in an average office, when the temperature was at a comfortable 25oC, employees only made a 10% error rate in typing. However, when the temperature was lowered, error rates rose to 25%. Even more recently, another study that used even more drastic differences in temperature found that employees committed 44% more errors in a colder environment, and were less than half as productive. Though the circumstances surrounding each experiment differed, the message is clear – colder offices drastically impact productivity, so looking after your heating and cooling systems is an absolute must.
Why Are We So Susceptible To Cold?
One of the key reasons that the temperature of an office affects our rate of work is reasonably simple – when we’re cold, we’re not just uncomfortable, we’re distracted. When our body temperature drops, it means we’re automatically expending more energy to keep ourselves warm, which leaves less brainpower for the tasks at hand. Concentration, inspiration and insight are the three golden currencies of the modern working world, and they’re resources that colder temperatures immediately deprive us of, leading to a very clear impact on our productivity.
Then there’s the mental side of heating and cooling systems – by turning up the air conditioning too much in colder weather, it makes people feel not just cold physically, but emotionally too. Yet more scientific studies have shown that when people feel chillier, they’re more likely to perceive others as being friendly or caring. This in turn can have an effect on teamwork and communication – a subtle one, yes, but still not something you want affecting your workforce, especially considered alongside the effects of their physical discomfort!
Here at Askews, we have 30 years of experience in looking after heating, cooling and ventilation systems for our customers, which means we can guarantee you a quality service from our expert engineers. Regular service and maintenance is key to the smooth running of your systems, so book yours today by giving us a call on 01282 863 825.
How does cold weather affect seniors?
Winter comes with sparkling snow, the holidays and some increased health issues – especially for seniors. It’s a good idea to know what to look for and expect so you can stay healthy this season or keep an eye on a senior you caregive for. Here are some ways winter can affect older individuals:
Falling risks increases
Seniors who live in climates that receive snow and ice during the winter are at an increased likelihood of falling. Those who live at home and do their own shoveling or yard work are especially likely to fall. However, even individuals who reside with caregivers and walk with supervision may be at risk. Make sure that areas around your home are shoveled and salted to prevent falls, and don’t hesitate to ask for assistance with these tasks. If you’d like someone to walk with you to the car to provide an arm to lean on, that’s OK. Consider using a walker to help you stay balanced while walking outdoors in the winter.
Falling risks also go up indoors during the winter because melted snow on the floor can prove slippery. A senior who has been outside and become very cold may have reduced mobility and balance and can fall while moving indoors. Always check on seniors when the temperature dips or snow and ice are present. Just giving them a call can provide insight into how the person is doing and assistance in an emergency.
Seniors should dress in layers and wear winter accessories to reduce the chances of getting hypothermia.
Potential for hypothermia goes up
Hypothermia occurs when the body becomes so cold it starts to shut down. The National Institutes of Health noted that hypothermia is a less obvious danger for vulnerable adults that requires immediate treatment. Individuals who are older are at an increased risk of hypothermia because their bodies cannot withstand the cold as long as younger people. It’s also true that some medications and illnesses can further heighten this risk.
Seniors naturally create less body heat, which means they are often colder than younger individuals to start with. Signs of hypothermia include slowed reactions and movements, sleepiness, slurred or slow speech and confusion. Wearing layered winter gear along with a hat, mittens and warm shoes can do wonders in preventing hypothermia. Also make sure your home temperature is set to 68 degrees Fahrenheit or higher. Seniors may want to talk to their physicians about any medications or chronic health problems that could increase their risk of hypothermia.
Heart troubles worsen
According to the American Heart Association, seniors who have cardiovascular conditions may experience increased side effects in the cold. Because lower temperatures and winds can reduce body heat, blood vessels tend to constrict, making it more difficult for oxygen to reach the entire body. The AHA recommends that seniors wear layered clothing to trap heat and provide insulation. Seniors who are thin are especially at risk of cold-related cardiovascular issues because they do not have as much fat to provide warmth and keep blood flowing.
Seniors often find their arthritis flares up in the cold weather.
Chronic pain often flares up
It’s common for seniors to have chronic pain like arthritis. When it’s cold outside, many people note their symptoms worsen. This can lead to taking excess pain medications, whether prescribed or over-the-counter. Talk with your doctor if you find your joints are more painful than usual. Physicians may recommend changing your medication or trying home remedies like Epsom salt baths to relieve the aches.
Sleep habits are altered
During the winter, the amount of sunshine is typically far less than during the rest of the year. This can make anyone feel sluggish and want to sleep more. Getting extra rest isn’t a problem until sleeping becomes a huge part of the day. Seniors may want to consider setting an alarm to wake up for breakfast and ensure they’re not staying in bed late because of the winter darkness. Keeping a regular schedule can be a big help in avoiding sundowners syndrome, as can opening the blinds and turning on the lights during the daytime.
It has been quite a year for Indiana gardeners already, and it has only just begun! We’ve had just about the whole range of possible weather from drought to flood and late frost to blazing heat.
Recent cold weather has frustrated many vegetable gardeners. Plants such as tomatoes, peppers, beans, squash, cucumbers and melons must be successfully pollinated in order to produce their fruit. Extreme temperatures, below 55 F or above 90 F, will dramatically decrease pollination. Fruits that do form may appear distorted when they mature later on. Southern crops such as okra, lima beans and sweet potatoes are even more sensitive to cold. Not only will the okra and limas not set fruit, their roots likely will not grow much during cold weather.
Seed germination and development of all warm-season crops will be slower in cold weather, so for late sowings of vegetables they may be delayed, or may even rot in relatively cold, wet soil. This may also lead to perfect conditions for “damping-off,” a fungal disease that attacks germinating seedlings.
The good news is that many of our cool-season vegetables, which more typically give up by this time of year, are still thriving. If they made it through the earlier-spring hot drought, crops such as lettuce, spinach, peas and radishes do best in cool weather.
Thunderstorms have been scattered, so some areas may still be on the dry side while others may be under water. Excess water, along with cool temperatures, can cause the appearance of blisters or bumps on leaves and stems. This condition, called oedema, is caused by too much water in the individual cells. Eventually, the cells in these bumps burst and often become corky and brown in appearance as they dry out. Oedema is not an infectious disease, nor is it a serious problem. Plants will outgrow the minor damage.
Whatever the cause of plant stress, gardeners should be ready to water if dry weather returns. In areas of heavy rains, side-dressing with nitrogen fertilizer will help replace that which was washed away during the downpours. And be prepared for more “weather” this summer!
How do cold temperatures affect plants?
For more information:
Premier Tech Horticulture Office
1, avenue Premier
Canada G5R 6C1
T: +1 418 867-8883
Toll free: +1 855 867-5407
Email: [email protected]
Publication date: Fri 9 Feb 2018
- Something went wrong with your message. Maybe it was seen as spam, please browse some more articles on our site before trying again.
email this article
Receive the daily newsletter in your email for free |
Other news in this sector:
- 2020-01-30 What does good pollination look like?
- 2020-01-30 Confusion about diffused light clarified
- 2020-01-30 Ethiopia will irrigate more than a million hectares before September
- 2020-01-29 “Enrich your data-set, realize yield prediction”
- 2020-01-29 Up to 15% cultivation speed increase with ‘Grown with WaterWick’ concept
- 2020-01-24 Dutch companies build app to share ornamental horticulture knowledge
- 2020-01-23 Chinese engineer reveals how he grew the first ever plant on the moon
- 2020-01-23 Model the climate and the crops: bring your production to the top
- 2020-01-22 Hydroponic farming of wheat, spinach and sword lily
- 2020-01-22 Specifying irrigation needs for container-grown plants
- 2020-01-22 Top 10 tablet tools
- 2020-01-20 5 digital horticulture practices to bring into 2020
- 2020-01-17 “We don’t manage. We teach people and give them our knowledge”
- 2020-01-16 Preventing issues in spring crops: Sanitation, Dips and Bio tips
- 2020-01-15 “Without proper pollination, all greenhouse techniques are reduced to nothing”
- 2020-01-14 How much water do your woody ornamentals really need?
- 2020-01-10 US (MD): Aquaponic flower experimentation
- 2020-01-02 “Improper cleaning and disinfecting results every year in stronger, more resistant bacteria and fungi”
- 2019-12-24 Sustainable and safe greenhouse crop production
- 2019-12-24 A year of irrigation water becoming better and better
How to Spot Cold Weather Damage on Your Plants
Are your outside plants looking a little sad?
Don’t give up hope on them just yet! We have a list of tips and ideas to guide you through taking care of those plants that have been damaged by the cold snap we’ve experienced. Typically, temperatures falling below freezing will quickly damage or even kill many types of plants. However, with prompt care, many of these cold damaged plants can be rescued.
Here in the Midlands, the January cold snap, especially following the warm November and December have affected plants that are generally cold hardy.
Take a walk through your yard and look for these signs on your camellias, tea olives, hollies, and podocarpus:
- If leaves that are typically green in the winter have turned brown, resist the temptation to “fix” them. Don’t do anything right now.
- Wait until the weather warms up and then fertilize after April 1 with a general tree and shrub fertilizer.
- Wait until after new growth appears to prune away dead branches.
- Camellia buds may drop without opening into full flowers. There is nothing you can do about that. Next year protect your camellias with a blanket and Christmas tree lights if you want to preserve the buds during a hard freeze.
Sometimes plants such as azaleas, pittosporum, hollies, gardenias, and mimosa trees won’t make their damage seen until the heat kicks in about June.
- If you see branches beginning to yellow and die out this summer, look closely at the bark on the dying branches. If you see that the bark has split, this is due to the sap freezing in January.
- When the plant tries to function in the summer, it can’t get enough water and nutrients up its stems, so it dies back.
- If the affected areas are just some of the limbs, you can cut out the dead material and let the plant recover.
- If the primary trunk is affected, the plant may not survive.
Plants that are rated Zone 8 & higher such as lomandra breeze grass, oleander, bottle brush, lantana, and angel trumpets may have been severely damaged during the January freeze.
- Fertilize with a general tree and shrub fertilizer after April 1.
- Wait until the weather warms up and look for new growth pushing out. If you get new growth, the plant survived.
- Cut back dead plant material and wait for the plant to recover through the summer.
- If you don’t see new growth by June, dig it up, throw it away and plant a new one.
- If the cold got to your Zone 8+ Sago Palms, they may look particularly dead and unattractive right now. Don’t do anything.
- Fertilize with a palm tree fertilizer after April 1. We recommend Carl Pool Palm Food. Or if you have had problems with scale on your Palms in the past, use Fertilome Palm Tree Food with Systemic Insecticide.
- New growth will appear out of the center of the palm in late May early June.
- Wait until after the new growth appears before you cut off the brown fronds.
How much cold will kill a plant is not an easy question to answer. Be sure to look up the cold hardiness for the plant in question before leaving the plant outside. Some plants can survive sub-freezing temperatures for months while others cannot take temperatures below 50 F. (10 C.) for more than a few hours.
Here in the Midlands, we are rated zone 8a. The average extreme minimum temperature for zone 8a is 10-15 degrees. Coastal SC is rated zone 8b. The average extreme minimum temperature for zone 8b is 15-20 degrees. If a plant is rated hardy for Zone 8-10, it should survive temperatures that fall as low as 10 degrees. However, we have found that some zone 8 plants are hardy to zone 8b but less so for 8a. In other words, they will survive 15-20 degree temps, but not less than 15-degree temps. Also, we have found that a plant might survive one night of 14-degree temp, but several nights in a row will do it in. Also, remember that if a plant is rated hardy for zones 8-10, it likes warmer weather since zone 10 is South Florida. Zone 8 is its northernmost border of survivability. So, a zone 8-10 plant would be potentially more susceptible to extreme cold than would a zone 7-9 plant.
While saving frozen plants is possible, freeze damage to plant tissue and other cold injuries can often be prevented. When frost or freezing conditions are expected, you can protect tender plants by covering them with sheets, burlap sacks, or “frost cloth.” These should be removed once the sun returns the following morning. It’s vital as a gardener you watch the weather forecast and protect your plants when needed.
Here at Wingard’s Market, we specialize in providing outstanding customer service, offering professional gardening advice, and answers to your everyday gardening questions. Stop by and visit our Beautiful Gift Shoppe and Fresh Produce Market while you stroll under century-old pecan trees. It’s truly a Garden Wonderland!
Located at 1403 North Lake Drive in Lexington, SC. Call us at (803) 359-9091
What Happens to Plant Life During the Winter?
carpathians fur-trees in the winter image by Vitalii Gavryshenko from Fotolia.com
Annual plants die in the fall after they scatter their seeds directly on the ground or include them in fruit that is consumed by animals and deposited elsewhere. Their seeds contain hormones that cause them to germinate in the warm spring weather that follows winter cold. Perennial plants, deciduous woody shrubs and some trees go dormant in the winter and begin growing again in the spring. Evergreen trees and woody shrubs conduct photosynthesis at a reduced rate.
Trees store reserves of nutrients during the spring and summer growing season. When the days begin to shorten, the temperature falls and the light spectrum changes from blue to red, hormones tell the plants to bear fruit and begin dropping their leaves in preparation for going dormant during the winter. As the green chlorophyll needed for photosynthesis disappears, the leaves turn orange, red and yellow.
Evergreen trees conduct photosynthesis at a reduced rate during the winter, especially during periods of thaw.
Winter Water Loss
Freezing temperatures and frozen water make water a scarce resource for plants in the winter. Sap in tree trunks and branches contain water that is sometimes frozen but is made available by thaws. Snow can insulate the ground keeping it from freezing so that plants can draw water from the soil; conifer needles below the surface of snow can absorb water from the snow.
Plants that are dormant, not conducting photosynthesis or losing water from their leaves need less water. Leaves lose water through their pores, called stomata, a process called transpiration; to avoid loss of water in the winter, deciduous trees drop their leaves.
The needles of evergreen conifers last two or three years before they are shed. The needles have a thick waxy coating and tighter pores to prevent the loss of water. The dark needles absorb more heat; this helps them survive winter cold but a warm spell causes the needle temperature to rise, resulting in a loss of water through transpiration.
Long tubes called tracheids form the xylem or vessels that move water within trees. The cohesive properties of water allow it to be “pulled” through the adjoining tracheids in continuous columns. As ice forms, it expels gases that cause spaces or breaks in the column of water.
In an evergreen, the expanding ice seals the ends of each tracheid, forming “floats” that function as valves. Each float is called a torus. The tracheids have strong cell walls that retain the gas expelled when ice forms; as the ice melts, the gas is forced back into the water, opening the tori and restoring the water column.
When deciduous trees emerge from dormancy in the spring, they grow new xylem cells to re-establish columns that might have been broken during the winter.
Snow can collect on conifer needles causing branches to break, so conifers have fewer branches growing to the side. Their branches point down, not out, allowing them to shed snow more easily. The fibers of their wood are usually longer, making the branches more flexible.
Plants in extremely cold climates in high altitudes or northern latitudes are often smaller, enabling them to stay beneath the insulating snow in the winter and avoid cold winds and blowing ice. The needles that conduct some photosynthesis year round help make up for short growing seasons in extreme northern latitudes.