Purple Christmas Cacti Leaves: Why Do They Turn Purple?
The reason why the tips of your cactuses turn purple is because they have been exposed to ultraviolet light. UV rays cause chlorophyll to break down into its constituent parts, which include sugars, amino acids and other compounds called carotenoids. These carotenoid pigments give plants their color. However, when these carotenoids are present in sufficient amounts, they become toxic to humans. If too much of them accumulate in our bodies, it causes cancer. The amount of UV radiation that can damage human cells depends on several factors such as skin type and age, sun exposure time and latitude. According to the U.S. National Library of Medicine, the average annual maximum solar ultraviolet (UV) dose received by Americans is between 2 and 4 millirem per year. For those living in areas with high levels of sunlight, this number increases to approximately 10 millirem per year.
As you might expect, most people do not live near the equator where UV radiation is greatest. People who live above the 35th parallel north or below the 35th parallel south experience a different amount of UV radiation than people living in lower latitudes. The lowest annual maximum UV radiation levels are experienced by those who live in the extreme northern United States and southern Canada, while the highest annual maximum levels are experienced by those who live in Australia. For instance, someone who lives in Los Angeles, California receives 2.1 millirem of UV radiation per year on average.
If the same person moved to Anchorage, Alaska, their average annual maximum UV radiation level would increase to 12.1 millirem per year.
Although UV rays can be beneficial in small amounts, they can be very harmful when exposed to for long periods of time. Possible effects of prolonged sun exposure include skin cancer, immune system suppression, photo aging and cataracts. The best way to avoid these effects is by limiting your sun exposure. If you must be out in the sun for extended periods of time, wear sunscreen and protective clothing.
The U.S. Food and Drug Administration has approved over-the-counter sunscreens that can help block UV rays from your skin. (add reference) It is better to prevent cancer than to treat it after the fact. Do everything you can to protect yourself from sunlight.
Common Cactus Problems
Cactuses are popular among plant enthusiasts for several reasons. They require very little care, are easy to store and their pads can be used for juicing. Many people keep cactuses on their desks at work or in their living rooms. If you have a cactus that you want to keep around for a long time, it is important to take good care of it.
Nurturing your plant will help it grow and stay healthy. However, certain issues can cause cactuses to become sick or die. It is important to know what these issues are so you can take immediate action.
Overwatering: Overwatering is one of the most common reasons why cactuses die. This happens because people water their plants too much. It is important to make sure that the soil is dry before you water it again. If the top layer of soil becomes dry, it is time to water your cactus again.
Overwatering can cause the roots of a cactus to rot. The plant may also develop fungal growths in its pads if watered too much. To prevent rotting and fungal growth, make sure you never let the water sit in the tray underneath your cactus for too long. Water should be drained out of the tray daily.
Underwatering: Underwatering is just as common as over-watering when it comes to cactuses. It can be difficult to tell if your cactus needs water or not because the top layer of soil may feel dry, even if the soil below is still moist. The best way to know for sure if your plant needs water is to pull it out of its pot and inspect the roots. If they are tight and firm, then your cactus does not need water.
If they look dark and mushy, it needs water immediately.
If you do not water your cactus for an extended period of time, its pads will start to shrivel up. This may also cause its coloring to fade and its skin to become brittle. Make sure you water your cactus on a regular basis so this does not happen.
Stress: Cactuses can become stressed if they do not receive the proper amount of light or if there are extreme changes in their environment. The pads will start to fade in color and will become weak when a cactus is under stress. It may also cause the cactus to grow taller than usual.
If you see that your cactus has started to grow taller and its pads are fading in color, move it to a sunnier location. If there are no sunnier locations in your home, you can place a lamp next to the plant. You can also move it to a different area of your home that has a higher temperature. Make sure you do not over water or over-stress your plant when you make the move.
If you cannot move your cactus to a sunnier location or under a light source, it may be best to start all over again with a new cactus. Many people assume that their cactus just needs water, so they continue to water it and other give it sunlight when it is experiencing too much of either. This can make the problem worse because there are natural changes that occur within all living things that are perfectly healthy.
Pests: Cactuses have few natural predators in the wild. However, this does not mean they do not have many pests that like to attack them.
One of the most common pests that attacks cactuses are insects such as aphids and mealy bugs. These insects suck the sap from the plant, which can cause the cactus to become malnourished. This allows pathogens to enter the body of the cactus and infect it with diseases. Aphids and mealy bugs typically attack younger cactuses that are still growing.
They will leave older and harder cactuses alone.
You can typically see aphids and mealy bugs on the pads of the cactus. They stick out because they look like little white or green insects that are moving around on the surface. You can eliminate these pests by spraying your cactus with a strong stream of water. Always be sure to thoroughly inspect your cactus after spraying it with water to ensure you got all of the pests.
Other insects such as caterpillars, moths and butterflies may also feed on the pads of your cactus. You can typically see these pests crawling on the surface or on the underside of the pad where they have eaten away at it. If you notice any of these types of insects on your cactus, it is best to eliminate them as soon as possible before they do too much damage.
You can use a strong spray of water to knock the pests off of the cactus. You can also use a spray bottle filled with alcohol to do the same thing.
You should never use broad-spectrum insecticides on your cactus such as Raid or other products like it. Most of these chemicals will cause more damage to your cactus than the insects you are trying to eliminate.
Also, try to avoid spraying water on your cactus in the hot sun as this can also cause damage. Always thoroughly inspect your cactus after treating it with water.
If you do not see any insect pests on your cactuses, you do not need to water them. This may sound counter-productive, but many people make the mistake of watering their cactuses too much, which can cause more harm than good.
If your home is currently hot or cold, it may be throwing off the natural cycle of when your cactuses need to be watered. Cactuses tend to hold onto water and they do not need to be watered as much in hot weather and they tend to lose moisture faster in cold weather.
All cactuses are different, so you will need to learn the needs of your particular plant. Get to know how it looks and acts normally so you will know if anything is wrong with it.
Most cactuses will have a white pores or strands on the pads. These are meant to absorb the moisture in the air. When the humidity is high enough, these will glisten when you view them during the day. You can also lightly press on the pads to see if they are soft.
This is another good way to tell if your cactus needs water or not.
If the pads are hard, this means it does not need water and if the pads are soft, it means it needs water.
You only want to water your cactus when the pads are soft. Over-watering your cactus can cause more harm than good. When in doubt, do not water it or wait until the next day to see if it still needs to be watered.
A simple cheap way of determining whether your cactus needs water is to get a small coffee can or similar container and put a few holes in the bottom for water to drain out of. Stand this below your cactus, and when it starts draining out, your cactus needs water.
You shouldn’t be feeding your cactus any form of fertilizer. If you do need to feed it anything, use only organically grown produce or animal parts.
Most cacti do not require any special feeding. You can feed them either once a month or once every six months. You can give them milk, eggs, insects (if they are available), or any fruits or vegetables that have little to no additives in them.
Acquiring your cacti
If you have a good way to transport them and can acquire them without breaking the law, try to find yourself either a barrel cactus (the big ones that look like something out of western movies) or a fishhook barrel (much smaller, green in color). Both are native to Arizona and very hardy. Other types of cacti may require more specialized care.
If you already have pet cacti and want more, try carefully taking a cutting or two from your larger cacti. Make sure to keep them wet and within a couple of days you should see new growth starting to appear.
Your average grocery store is certain to carry at least one kind of cacti. Some of these may be difficult to grow depending on where you live, so do some research on the type you want to get before you commit to getting it.
If you should happen to come across a cactus with yellow or orange colored pads, DO NOT TOUCH IT! These are most likely beaver tails and can inflict a very painful sting.
These are just some of the many types of cacti that can make great pets. If you’re an outdoorsy type of person then these plants might be for you. Just remember that like any other pet, proper care is essential in order to guarantee a long and happy life.
Take care of your cacti, and your cacti will take care of you.
Sources & references used in this article:
Effect of gibberellin on the flowering of Christmas cactus. I by K FUJIHARA – Journal of the Japanese Society for Horticultural …, 1959 – jstage.jst.go.jp
Control of Basal Stem and Root Rot of Christmas Cactus Caused by Pythiwm aphanidermatum and Phytophthora parasitica by JF Knauss – Proceedings of the Florida State Horticultural Society, 1975 – journals.flvc.org
New diseases and records of some important flower plants caused by Phytophthora parasitica in Taiwan by PJ Ann – Plant Pathol. Bull, 1992 – 220.127.116.11
Cobb County Extension Service by H Plants – Citeseer
FERTILIZATION OF CHRISTMAS CACTUS by RT Poole, CA Conover – HortScience, 1990 – journals.ashs.org
Cactaceae plant namedWindsor by GD Rowley – The National Cactus and Succulent Journal, 1969 – JSTOR
Cactaceae plant namedSanibel by BL Cobia, ME Cobia – US Patent App. 07/621,066, 1992 – Google Patents