Growing Basics
Carnivorous Plants is an awesome term, but what does it actual mean in practice? Through the past 200 years, that's changed as scientific understanding has improved. Generally speaking, there's several components. To be a “true” carnivorous plant, the specimen must: possess a method to capture prey, be able to digest that prey item, and be able to absorb the nutrition from the prey. Many plants have at least one of these adaptations, but there's only a small fraction of the plant kingdom that meet the definition in full. Most of the time, these adaptations evolve to allow the plants to access nutrition that their soil does not possess. Though first, let me introduce you to the various kinds of carnivorous plants that exist.
First thing is first, for something to be a carnivorous plant then it must capture prey. Extant, or currently alive, carnivorous plants do this through a variety of different trapping mechanisms. Pit fall traps, fly paper or “sticky” traps, snap traps, catapult traps, lobster pot traps, and vacuum traps are the primary forms of capture.
Pit fall traps operate by having a shaft or tube shaped leaf with a single opening that narrows after the entrance. These traps are effective for attracting flying insects as most pit fall trapping plants will have rows of downward facing hairs lining their interior. These hairs make it difficult to back out of the pitcher and effectively pins most flying insect's wings to the walls of the trap. Some species of pit fall trap using plants will even have hairs on the exterior of the trap to allow small ground dwelling insects like ants to climb to their doom. Brocchinia, Catopsis, Cephalotus, Darlingtonia, Heliamphora, Nepenthes, and Sarracenia utilize this method of capture.
The next kind of trap, the fly paper or sticky trap. These traps operate by using usually modified trichrome structures to produce incredibly sticky mucilage that looks prismatic and attractive to prey. Once an insect lands on the plant, it struggles against the mucilage. After some time, the insect dies from exhaustion. Fly paper trap plants include Byblis, Drosera, Drosophyllum, Pinguicula, Roridula, Triantha, and Triphyophyllum.
Before we move into the more interesting and thought provoking trapping methods, I'd like to slow down and appreciate the weird lobster pot traps of Genlisea. A lobster pot trap is a modified root that is hollow and has a small opening on the end. This opening leads to a corkscrew shaped cavity inside the root the spirals upwards toward the leaves and stolon of the plant. Hairs inside the root make it extremely difficult for prey to turn around and exit the root. This trapping method is unique to Genlisea.
Snap traps are probably the most well known of all carnivorous plant capture methods. Employed by only two genera, Aldrovanda and Dionaea, the Waterwheel Plant and Venus Flytrap, this is one of the more impressive forms of prey capture. These plants work by having a few trigger hairs inside an almost heart shaped leaf structure. When prey touches these hairs multiple times in quick succession, the plant rapidly fills the leaf tissue with water causing the heart shape to quickly snap shut. The leaf edges are modified with tooth-like structures that act to prevent trapped prey from escaping. These traps make these two plant genera some of the fastest moving living organisms out of all species in the tree of life today, not just plants. What makes Aldrovanda particularly impressive, it closes with a similar speed as the Venus Flytrap underwater! It has to overcome the added difficulty of water displacement and resistance from the water. That's a lot of force for a plant.
Now for the coolest capture method, the catapult trap. This is a trap unique to specific Drosera species. The outer sticky traps of these plants are modified into almost a “V” shape. When prey touches these hairs, they're catapulted at incredible speeds to the center of the leaf and the numerous sticky traps awaiting the poor prey item.
Last, but certainly not least, are by far the most impressive and complex of the trapping methods. Utricularia, or the Bladderworts, use traps resembling the shape of a balloon. One one side are a series of trigger hairs surrounding the opening. Once prey touches these hairs, the balloon or “bladder” will rapidly inflate sucking everything around into itself at incredibly fast speeds.
Now that we've covered how carnivorous plants trap their prey, the next point to address is digestion. Most carnivorous plant species possess specialized digestive glands that produce enzymes to break down the prey they capture. This is where most of the “proto”- carnivorous plants fall short. There's examples of many plant species who utilize a capture method for prey, but as of current scientific understanding at the time of writing this, they are not known to directly digest their prey.
To be incredibly technical, there are genera like Roridula that do not digest their prey. They instead rely on assassin beetles to digest their prey respectively. Going by the current definition, that makes them genera proto-carnivorous. From my horticultural stand point, the care and conditions they require is no different than other plants utilizing their capture methods. This is why I personally consider them “true” carnivorous plants in my personal views. I take the view point that symbiotic relationships should be counted as valid digestion. These plants conserve their energy on digestion by outsourcing it to whatever organism in their environment is most up to the task. Even in the more rigidly defined carnivores we can find symbiotic relationships with other organisms, which supports that it's an advantage to outsource the digestion. This has led to very intriguing relationships, such as crabs living in Nepenthes pitchers in the rainforests of South East Asia. Another great example would be Sarracenia Purpurea, which also relies on bacteria and mosquito larvae to digest the prey it captures. The mosquitos uniquely found in Sarracenia Purpurea are predatory and eat the one mosquito species that attacks humans! That's a symbiotic relationship I'm sure we can all get behind.
With two of the criteria of the carnivorous plant definition knocked out, let's tackle the last one, absorbing nutrition from digested prey. Of all three of the parts of the classical definition, I admit, this is vaguest part. Why? Almost all plants can absorb nutrition via osmosis if it's readily available and in higher concentration on the leaf's surface. Plant roots work by using osmosis to pull in nutrition, so where exactly is the line drawn? From the scientific perspective, if a plant is utilizing a trapping mechanism and has a digestive method, it will usually possess specialized glands for digestion.
Thankfully, genetic testing has revealed several more precise methods for defining this uptake as almost all of the true carnivorous species possess this gene. When geneticist use this particular gene which is linked to nutrition uptake beyond what osmosis would provide, to look at the rest of the plant kingdom, some interesting results are coming back. Plant species like Triantha Occidentalis have this gene, despite never being considered a carnivorous plant for most of its known history. Further testing revealed that this species of grass actually has a carnivorous flower stalk and is among the true carnivorous plants!
SOIL
The first place to start with cultivation of any plant is the pot and soil. Most other conditions like water, light, and temperature can change throughout the year, however the soil and pot rarely change during the life of a plant. For best results, you will have to replicate the conditions the plants prefer in nature. That's why it's important to understand what kind of pot to put a plant in and what soil the plant prefers for best success. In this section we will go over the different kinds of pots that carnivorous plants prefer. We will then go over the kinds of soil they grow in nature and how you can best replicate that soil at your home.
Most carnivorous plants tend to make a tap root straight down. This means you should account for the size of your plant and it's future growth. Venus Flytraps can grow in 1-3 inch deep pots, but perform best in 7+ inch deep pots. Mexican Butterworts rarely have their roots go farther than a inch down. Later in this book, I will give a recommend pot size for each plant genus for you planning. Next is planning what material to use for the pot.
Carnivorous plants usually occur in nutrient poor bogs, where rainwater and decaying material are the only sources of the Nitrogen the plants need to grow. As a result of this poor quality soil, Carnivorous Plants tend to have no way of preventing excessive amounts of nutrients from rapidly entering the plant's system. This shock from the salts and nutrients will quickly kill the plant. This is why you want a pot made of a material that does not leach minerals into the soil. Pots made of plastic, glass, or glazed ceramic will work.Wooden containers with plastic liners also work. The pot should also have drainage.
Carnivorous plants are often watered from the bottom of their pots by filling a saucer or tray up to a quarter of the way up the pot. A small container like a saucer or tray should be factored in for individual plants. Individual plants can be placed in an undrained container, but constantly waterlogged soils can lead to nasty bacteria and other organisms to grow uncontrolled without a vigilant eye.
Now, onto soil mixes these plants occur in. In nature, carnivorous plants tend to live in wet, open, and nutrient poor locations. Wide sunny fens, bogs, and hillside seeps are likely places to find these plants. These habitats are all around the globe and have vastly different soils from location to location. Here's a breakdown of all the common soil ingredients growers will use.
Long Fibered Sphagnum Moss
Long Fibered Sphagnum Moss is one of the most commonly used mediums in carnivorous plant cultivation. Sphagnum moss is remarkable for the ability to retain large amounts of moisture. This moss is also known for having anti fungal properties and used to be used as wound dressing prior to the invention of bandages. Bonsai nurseries use dried long fibered sphagnum as a medium to help nurse trees suffering from root rot back to a healthy state. Many carnivorous plant species are found in sphagnum moss bogs in the wild. This relationship is because of the acidic environment the sphagnum moss creates. Long Fibered Sphagnum Moss grows throughout the globe and comes in both live and dried forms commercially.
Peat Moss
As sphagnum moss decomposes in the bogs over time it becomes a brown material known as peat. Peat moss retains most of the acidic nature of sphagnum moss and tends to be poor in nutrients. This makes peat moss a great cheap alternative to sphagnum moss, both alive and dried. Peat moss will compress and clump over time. To avoid clumping or compression, use peat with another soil ingredient to provide good drainage. Some manufacturers will add fertilizers to peat moss. Make sure to get non-fertilized peat moss by reading the product labels before purchase.
Silica Sand
Silica sand, or pool filter sand, is great at providing a drainage to compacting mediums. Play or River sand can have many minerals that can harm carnivorous plant species. Usually commercial nurseries that ship plants will stray away from sand, as it adds a large amount of weight to the plant. This extra weight means shipping costs will be higher.
Akadama
A volcanic clay from Japan. This is a highly praised soil additive that Bonsai has used for hundreds of years. Recently, Nepenthes growers have started using this clay to great success. This clay provides great drainage, but can breakdown and prevent drainage as it ages.
Perlite
One of the most common soil additives used by nurseries. This light weight rock is artificially produced and provides light weight drainage to mediums. Some manufacturers will add fertilizers to perlite. Make sure to get non-fertilized perlite by reading the product labels before purchase.
Vermiculite
This is a naturally occurring mineral found in many places around the globe. Vermiculite has a history of being used to provide increased drainage for potted plants.
Lava Rock
This rock is formed from volcanic eruptions and provides unique properties that allow for some interesting horticultural uses. Lava rock can wick moisture either out of a medium or from a tray into a medium. Butterworts and lithophytic (rock growing) plants can be planted direct on lava rock.
Pine Bark
As some of the carnivorous plants are native to pine forests or other acidic forest soils, they can appreciate some tree bark in their soil mix. This not only provides additional organic matter, but also increases drainage and soil's acidity.
Fluval Stratum
This is a more new development and is being used by Pinguicula, Drosera, and Heliamphora growers to great success.
While you're free to experiment with these ingredients to find what works best for you, I would suggest starting with these soil mixes first and adjusting them based on your needs and observations.
1 Part Peat Moss : 1 Part Perlite
1 Part Long Fibered Sphagnum Moss : 1 Part Perlite
1 Part Silicia Sand : 1 Part Perlite : 1 Part Vermiculite
1 Part Peat Moss : 1 Part Silica Sand
All carnivorous plants want well draining mixes. Most of them want an acidic mix, but a few plant species prefer a more mineral heavy and neutral mix. The sand and perlite in these mixes prevent the heavy peat from compacting and preventing air penetration.
To mix these soil ingredients, I recommend using a large bowl, wheelbarrow, or even cement mixer and scooping one cup or shovel full of each ingredient at a time. Use a small cup of water to wet the mix then use your hands to thoroughly scramble the soils together. If you have peat moss that is “dirty” with a lot of sticks and debris, use a pasta strainer and wash the peat until no brown water is washing through and remove any remaining debris by hand. Use as mineral free of water as possible. Once you've thoroughly mixed and wetted the soil medium, fill a pot loosely only shaking the soil into the pot. Do not press the soil down as it will be too compact for the roots of the plants to penetrate with ease.
WATER
Water is equally important to a plant as the soil or pot. Plants have quite dramatic responses to being under or overwatered. Even the quality of the water can have a profound effect on how a plant grows. This is why it's important to understand how water relates to a certain plant you have no familiarity with it's habitat. In this section we will discuss how a bog's water level operates, what is water quality and how to measure it, and the watering methods used for carnivorous plants.
In nature, bogs are low lying areas with pools of water that usually do not have flow. Water will enter the bog from rain pooling from surrounding areas. Bogs are naturally nutrient poor as rainwater contains almost no minerals and as it flows through the soil it removes salts and nutrients. The water level of these areas raises and lowers depending on the amount of rainfall versus how much evaporates. This is important to note as some of the carnivorous plants do spend parts of the year underwater, some will only rarely be found underwater during flooding rainstorms, and others still never exist underwater. As the water lowers, air is pulled into the ground allowing the root systems of the plants to breathe. This cycle of air entering the soil prevents rot in the otherwise vulnerable root systems.
Understanding how a bog functions is incredibly helpful in understanding how to water carnivorous plants. The most difficult part for some beginners is replicating the water quality. Water quality as it relates to carnivorous plant cultivation is measured with the Parts Per Million of Total Dissolved Solids in the water. Parts Per Million (PPM) of Total Dissolved Solids (TDS) refers to the amount of minerals or other tiny solids that you may or may not be able to see within the water. Carnivorous plants want a TDS reading of 100 TDS or lower. If you have tap water below this threshold, you may use it. To measure TDS, there are meters on Amazon that are inexpensive and easy to use.
Tap water is to inconsistent throughout the world for me to be able to say for sure if it can or cannot be used. Generally speaking, most treated tap water will work if put through an activated carbon filter. Brita or ZeroWater pitchers work great for small collections of plants. The Activated Carbon filters will strip out almost all the harmful charged salts from water. The main issue is volatile organic compounds which are much more harmful and require much more filtration to remove than most consumer level filters can provide. Thankfully, most water throughout the United States is free of these compounds and allows almost all growers to get by with a simple pitcher filter system.
As for larger or more meticulous grows, like full grow tents or greenhouses, I'd recommend looking into Reverse Osmosis Filtration. It's a process that removes all other impurities from water, leaving it below 10 PPM of TDS. This kind of filtration is great for the most sensitive of plants or for growers looking to provide extreme consistency to their process. Many grocery stores around the country have water refilling stations that provide Reverse Osmosis water for under $1 per gallon. If you don't want to haul large 5 gallon bottles home, which the ones for office water coolers work great, then look into a filtration unit to install in your own home. These often require some knowledge of plumbing to install correctly and are incredibly wasteful. Expect 4-6 gallons of waste water per gallon of clean and filtered water. For this reason, I highly suggest using the Grocery Store refill units for as long as possible for your collection.
Now that we know what we're looking for in the quality of water, how does one properly water a carnivorous plant? There's two main two main approaches, top and tray watering. While easy in concept, it's important to understand how these approaches have effects on the oxygen levels available in the medium. Keeping this in mind will have a profound effect on your success growing these plants.
Top watering is when you use a cup, watering can, or some other container to pour water directly to the surface of the soil. This ensures the top level is saturated and best mimics the effects of rain water. The problem is that this method relies on you being readily available to check on your plants daily to make sure the medium isn't too dry. To make matters worse, some plants like Butterworts or some of the smaller Sundews can easily uproot or become buried if too much water is poured in at once. Other plants, like Nepenthes or Heliamphora are almost exclusively top watered. Top watering does have the huge benefit of pulling oxygen into the medium, but more on that later.
Tray watering is when you use a tray, saucer, cup, or any other container to provide water about 1/3 up the pot. Some species you can grow in constantly wet conditions, but this can cause nasty bacteria to form that will make your pots smell atrocious. The huge benefit to this method is that you will be able to spend much less time monitoring your collection. Usually a quick glance every other day is enough to check on the water levels. Since water evaporates at varying rates in different humidity levels and temperatures, it's difficult to say how many days your set up may go between watering. Aim to have the tray or saucer dry or almost dry before watering again. This will allow the medium to have oxygen pulled in as the water level drops.
Both of these methods have various benefits, but for the best chances of success, it is important to note soil oxygen levels. When the water evaporates in the tray or you are pouring water into the top of the pot, you are pulling oxygen into the medium. If you've ever grown carnivorous plants or other bog plants and notice a rotten egg smell or other unpleasant odors, it's caused from anaerobic bacteria growing in the medium. Sulfur is being let off, which produces the rotten egg smell, because oxygen is too low for oxygen loving (and not disgusting smelling) bacteria. The anaerobic bacteria can also cause start munching on the roots of your plants!
Speaking on the roots of the plant, soil oxygenation is incredibly important. Plants do breath through their roots as well as their leaves! This is why it is important to let the water level in trays drop to allow the roots of the plants to breath. Happy roots means better water uptake, which means better overall growth. However, if the soil dries, the plant dies. The roots are designed to uptake water, so they're the part of the plant most effected by dry environments. Carnivorous plants are usually found in rather wet habitats, such as bogs or fens. These places have natural cycles of raising and lowering water levels that provide the plants with adequate oxygen in their native soils.
Keeping this all in mind, tray or top watering have specific uses, but are both trying to accomplish the same thing. Provide water to the roots and allow oxygen to cycle into the medium. Learning this delicate balance will lead to much less degradation in your medium which results in less repotting overall. An added benefit is that you'll never get anaerobic bacteria growing that will make your pots smell nasty!
LIGHT
Light is one of the most fundamental keys to success in growing any plant. Without light a plant cannot produce sugars, which are the food of all plants. To turn light and various other raw components into sugar requires water, carbon dioxide, and various micro-nutrients. Not only that, but the area photosynthesis is happening cannot be too hot or cold. This is why all the other sections before this one are so important. All the factors you provide your plants directly have an outcome in how it will grow and react to light. However, light and lighting as it relates to horticultural is not easily or quickly explainable.
Photosynthesis is an incredibly complex process that is easily explainable, but has an incredibly amount of depth. Understanding the exact chemical processes is beneficial, but not necessary for growing plants successfully. Understanding what a photon is, will help in growing plants. Photons are the particle of light. When any atom goes from a high energy state to a low energy state, it often produces heat and/or photons. These particles travel out like a shotgun blast in all directions, bouncing off anything reflective until they run out of energy. How much energy the photon has relates to what part of the spectrum it falls on. Visible light is only a small part of the light spectrum.
Plants will utilize these different photons by use of an antenna complex of pigments that direct the photons into the areas where photosynthesis occurs in the cells. This is why plants have many different colors. Different light spectra will cause certain plants to produce pigments to better absorb the light, while others cannot and will slowly die as they have no sugar production.
For outdoor or windowsill growing, the Sun provides all the ranges of the light spectrum plants use. When growing indoors and in some lower light windowsills, it is important to try and replicate what the plants want in terms of that light spectrum. Generally speaking, carnivorous plants will grow well in blue or white spectrums. This section of spectrum is more like Spring to Early Summer Sunlight in areas that are temperate. There are red or orange lights the better replicate the Fall or Early Winter Sunlight in temperate areas. Red and oranges can cause flowering in some species, dormancy in others, and cause some to develop very strong coloration. This variability is the reason blue and white lighting is the best recommendation for all species.
Measuring how strong of lighting you have is another important factor. Since carnivorous plants can be found in a wide variety of habitats, they also have a wide range of lighting preferences. To measure indoor lighting, there exists many different light meters. Measuring PPFD, or Photosynthetic Photon Flux Density, is the most relevant for indoor use. Other measurements, such as watts or lumens, are not useful to horticultural applications. 250-300 PPFD of white or blue lighting at the surface of the pot will be sufficient for most plants. If a light meter is not affordable, most cell phones have free applications that can use the camera to give a good ballpark estimation of the strength. It can be especially useful in comparing two areas, but is no replacement for accurate measurements. Larger genera require usually require more powerful lighting, but they will obtain this as they grow closer to the lights. The farther you go from a light, the wider the “shotgun spread” of photons. This means that the lights are much more powerful the closer they are to the plant. If you notice your plant becoming sunburnt, you can either move it farther away from the light source or raise the light a few inches.
Brief List of Lighting Technology
T12 fluorescents – old and ineffective. These bulbs lose effectiveness over time and can become quite costly are a few years. Rather cool, but not as powerful.
T8 fluorescents – older lighting technology that is newer than T12. More effective than T12's, but they can become costly due to bulb replacements as the bulbs lose effectiveness over time.
T5 fluorescents - same issues as T8's and T12's, but much more powerful. Usually these lights require much more power and produce a lot more heat. This is at the benefit of more powerful lighting, however the bulbs lose effectiveness over time and can become costly to replace.
Ceramic Metal Halide – fairly efficient lighting, commonly used in indoor horticulture. Can be incredibly intense for an indoor grow, but can be effective for industrial growing.
High Pressure Sodium – fairly efficient, but this varies on the ballast and bulb. They are incredibly hot and require cooling.
LEDs – extremely efficient, usually long lasting, and can be found in specific light spectra ranges. This is the current and recommended technology to use for indoor lighting currently.
One of the drawbacks to any lighting technology is that heat is produced. Generally speaking, in hotter climates, 1 watt of lighting energy will require 1-3 watts of air conditioning to cool. Using more efficient lighting technology greatly reduces the amount of cooling necessary. The side effect is more efficient lighting is also cheaper as it requires less electricity. It is well worth the investment to buy LEDs than other technologies as they provide the best efficiency. This saves double on both cooling needs and the electric bill.
Lastly, the photoperiod, or duration of light the plant receives daily is critically important for long term care. In my own personal experiences, 14-16 hours of light indoors is optimal for most species. Plants do “sleep”, so giving them a dark period of rest daily helps their growth. Temperate plants can have dormancy induced by giving them a light cycle under 12 hours for prolonged periods of time. This is why plants growing under too weak of lighting look similar to those in the early parts of temperate dormancy.
FEEDING
Feeding Carnivorous Plants can be a strangely complicated topic. Across hobbyists, it's easy to notice that almost nobody does the same exact method. In this section, I'll attempt to give you all the options I know of and their drawbacks. You can decide what is the easiest for your own set up and personal schedule.
The old rule of thumb was for most Carnivorous Plants, 1 insect per month would suffice. I disagree with this notion and would recommend 1-4 depending on the size of the plant. As most plants get older and larger, they'll require more nutrition to maintain their size. As your plant gets larger, you should also increase the amount of food it is receiving.
Now, you're probably wondering if most growers have some crazy large stash of fruit flies or some other kind of insect? The answer is no, except for a few who keep reptiles and already have colonies. The rest of us growers are left to either using any poor insects we find in our homes or other methods. These other methods include using Fish Food Flakes, Dried Bloodworms, Osmocote (or other slow release pellet fertilizers for orchids), or Maxsea 16-16-16 (or any other fertilizer powder that mixes with water that has a lot of micro-nutrients).
Fish Flakes – can discolor the leaves of the plants from the dyes present as well as prone to molding.
Freeze Dried Bloodworms – same molding problem as Fish Flakes and not as pleasant to handle.
Osmocote (Pelletized Orchid Fertilizers) – these work great for pitcher plants, but can be too strong and burn the pitchers. Use caution and start low and slow when first using this kind of fertilizer on a plant.
Maxsea 16-16-16 (Powdered Fertilizers) – These products you mix into water and spray onto the plants. Start at ¼ strength the recommended amount on the label. I use Maxsea 16-16-16 at 800ppm-1000ppm strength for my collection. These kinds of fertilizers can cause algae to bloom on the soil if overused.
DORMANCY
Dormancy is the period of time, usually during the winter, when perennial plants are no longer actively growing. Old leaves will turn brown or black and new growth will resume when the weather changes. Annual plants will typically die off around this time and rely on their seeds to grow new plants whenever winter or other conditions are more favorable. Most plants can avoid going dormant with no problems, but there are a select few that require a cold period in order to survive.
To best understand why a plant goes dormant, studying the environment it comes from is key. Some go dormant out of necessity either from the temperature or, in the case of carnivorous plants, a lack of food. As winter rolls around in temperature areas, insect populations die out meaning the plants lack a steady food supply. From my own growing experiences, growers usually induce dormancy in like Sarracenia or the Venus Flytrap which can be grown indoors without a dormancy period. Feeding must consistent year round and their growing conditions cannot have low temperatures to trigger a dormancy response. Then there's the plants like Drosera Linearis that require intensely cold periods for 3-4 months in order to properly grow, which is why it's exceedingly rare in cultivation.
On the other extreme, you have Australian plants native to the Kimberley like Byblis or the Petiolaris Drosera. These plants only receive rain during a 3-4 month period and have different strategies for dealing with the lack of water. For Byblis, they'll flower vigorously and produce seed before the dry season, opting to grow as an annual. Petiolaris Drosera will retract to tight buds, exhibiting a “Summer Dormancy”. Another section with summer dormancy can be seen in Tuberous Drosera, instead they die back to small tubers underground. These strategies are adaptations that allow them to continue growing in such harsh conditions.
Some growers prefer to see plants grow through their lifecycle as they would naturally. Others, like myself, prefer to find methods to keep them vigorously growing year round. Both approaches are valid. To understand how to make a plant go dormant, first try to replicate the conditions that cause it to go dormant in the first place. For Venus Flytraps, this would be trying to replicate late fall in the Carolinas. Cool temperatures between 45-65F, a shorter light cycle, and lower availability of food are the environmental triggers to cause them to go dormant. If you wish to avoid yours going dormant, then keep the temperature above 65F, the light cycle above 14 hours on, and keep feeding consistent.
Overall, the topic of dormancy is becoming more of a debate than hard science when it comes to cultivating Carnivorous Plants. The definitive triggers to each genera's dormancy responses are poorly studied and in most cases can be circumvented in an indoor growing space. I strongly encourage more growers to experiment with their conditions and report the results online. This will help further the cultivation of these plants (and probably many others like them) in the future!
PEST & DISEASE
Pests are the bane of all gardeners. They destroy the foliage and can bring all kinds of diseases into your growing space. Diseases and infections are often the cause for even the happiest of plants to kick the bucket. What's worse, there's many different pests, diseases, and infections making identifying the problem a headache for a new grower. There's a wide variety of products to help treat these problems, but finding the solution that works best for a particular grow area can be challenging.
When dealing with pests, it's best to think of the plants as kids going to school. If one gets sick, they'll sneeze and cough on all nearby classmates who will then bring the sickness home to their parents. Same thing happens in almost every kind of growing environment. Pests and disease are usually brought in by one new plant. Sometimes they'll ride in on birds and bugs. This is why quarantining new plants in either a bag or separate domed area is recommended for the first 10 days. Keeping new plants away from your collection until you can safely determine they're clean will greatly reduce new pests from coming into your area.
When quarantining new plants and taking care of existing ones, you should keep an incredibly keen eye out for any signs of pests. Webbing, small dots that move, and extremely distorted growth are usually the earlier signs of pests. Catching them as early as possible increases the likelihood that treatments will work. This is why it's important to not just care for your plants, but also spend a few minutes every day looking them over. After some time, you'll be able to pick out what “unusual” growth means for the species you care for.
The best treatment for pests and diseases is always prevention. Quarantining is the first line of defense, but only works well in grow spaces that you can ensure no insects or unfiltered air are reaching the plants. Fungal spores can travel immense distances and even screened greenhouses will have spores enter whenever the doors are briefly opened. With this in mind, it's a fact that diseases or pests will eventually find their way into your growing space in most practical set ups.
This is why good airflow, strong lighting, and proper watering are critically important to long term growing success. Strong lighting and good airflow prevent fungus from forming on the top layers of the medium or on the plants directly. Good watering that oxygenates the medium properly is usually more difficult for disease causing fungus to inoculate. Top watering every month or two instead of only doing tray watering will control most diseases that are controlled in nature by rainstorms. Healthy and happy plants are much more difficult for disease and pests to attack.
Even the healthiest of plants can fall victim to disease or pests. When this happens, it's important to recognize that a plant is exhibiting stress. This stress can take the form discolorations in the leaves, leaves that are stunted or grow deformed, or black or brown spots forming. Once any of these signs is found, immediately start examining the plant. Pests will typically live either on the stems, near the base of the roots, or under the leaves. Basically all the areas that will be hard for you to readily see them. This is by design, as in nature this keeps them from being eaten by larger predators.
Usual suspects for pests are Aphids, Mealybugs, Scale, and Mites. Fungus gnats and spring tails can be found in most collections, but only Fungus Gnat larva will munch on the plants. There's a wide array of different fungus that attack Carnivorous Plants, including Fusarium and Powdery Mildew. Pitcher Plants can have a variety of molds that will grow on the rims of the pitchers that eats the nectar. Molds can usually be wiped off, but any fungus is an indication that humidity is too high for the level of airflow. Either decreasing the humidity or providing more airflow should remedy the problem moving forward.
Now, the hardest part, treating pests and diseases. I wish I could recommend a silver bullet product that would work in all cases, but there's likely not going to be one in my lifetime. In the decade I've been growing, I've found all kinds of products that will work in treating pests or fungal infections. More than half of them are no longer in production due to being terrible for human health. Most garden centers have these products and due to the ever changing nature of pesticides, it's hard for me to recommend an option I can guarantee will be legal and available where you are. Techniques like dunking a plant in water overnight or using Neem Oil have varying levels of effectiveness with most pests, but usually fail to completely treat the problem.
When trying to determine what product to use, you must known what kind of pest you are dealing with. Once you know if it's a mite or an aphid, you'll have a much easier time finding a pesticide product that's available and will work for you. Most pesticides will have what pests they treat clearly on the label, with a full list usually hidden behind a peel off sticker or on the package. For pesticides and fungicides, follow the instructions for perennial non-woody herbs. Apply in the evening and always in a ventilated space. FOLLOW THE INSTRUCTIONS ON THE LABEL.
Systemic pesticides and fungicides usually work best and can be used preventively once or twice a year (as the label directs). These work by the pesticide or fungicide being sucked up by the roots, making the plant toxic to the target pests. These products should be used as sparingly as possible, as using them increases the risk that one of the pests or diseases can build an immunity to the active compounds. The only thing worse than spider mites are pesticide resistant spider mites.
WHERE TO GROW
Now that basic cultivation is out of the way, where should you grow carnivorous plants? There's many different ways go about cultivating these wonderful plants, but it can be difficult to figure out which option is best for your situation. In general you can grow carnivorous plants outdoors in pots, outdoors in bog gardens, outdoors in a greenhouse, indoor on a windowsill, indoor in a terrarium or fish tank, or indoor on a rack with lights. There is going to be an option that will work for your space and personal needs.
Growing carnivorous plants potted outside has been a long term staple for the growing community. Most of the carnivorous plants that are cheap and common are usually native species to the US, like the Venus Flytrap or Sarracenia. These make for ideal outdoor patio plants as they can handle most climate zones throughout the country. In more northern portions, you'll be limited to plants like Sarracenia Purpurea that are adapted to the intense cold. Tropical plants will not be viable for most locations in the United States, save for tropical places like Hawaii, Southern California, Puerto Rico, and Florida. Outdoor growing in a large pot is a good option for growers who want minimal work after planting. Usually, you'll have to repot once every 2-3 years to keep the medium healthy. Growing outside means a higher chance of pest and disease exposure, so expect more of these problems over time.
Next option is to start an outdoor bog garden. These are usually lined beds that retain more water than the surrounding medium. Bog gardens provide an excellent display that can grow to look similar to natural habitats. Once again, you'll be limited in what you can grow by the climate of your area. Temperate plants make excellent choices for these gardens, especially the native species. Bog gardens tend to provide more space for larger plants like Sarracenia and will allow them to reach impressive sizes as they divide over time. As with growing outdoors in pots, pest and disease exposure are a huge risk.
Growing in a greenhouse is by far the most ideal solution for growers with large collections. Utilizing the sun to offset electrical costs for lighting and heating make them much more efficient than most indoor growing. Heating in the winter or cooling in the summer can be an issue, but many solutions exist to solve these problems. These solutions range from misting or ventilation systems, to air conditioners, and large heaters. Greenhouses can also be built to prevent the majority of pests from entering, providing much more protection than the other outdoor growing methods from disease and pest outbreaks. While not as secure as most indoor growing spaces, a greenhouse certainly provides a level of protection from weather damage as well. Greenhouses also have the benefit of a more easy to control climate. The temperature through heating and cooling can adjust to match the needs of the plants you intend to grow. In a temperate climate you can make a “Hot House” that can accommodate tropical plants year round. If you only want temperate plants, a “cold or cool house” with no winter heating is a valid solution. While much more expensive than other outdoor methods, greenhouses definitely provide every bit of value to cover the cost. The ability to control the environment more precisely usually means better plant growth as a result.
Terrariums, clouches, and fish tanks are the first indoor method for growing carnivorous plants. Historically, this has been how the majority of tropical carnivorous plants have been grown going back to 1950's. Terrariums and tanks benefit from being smaller and easy to maintain, but suffer from lack of airflow and there's a challenge to have bright enough lighting for the plants. With enough creativity solutions can be found, from computer fans to using LED panel lights. Sealed environments like clouches, sealed tanks, or terrariums with lids will often have fungal issues if kept constantly wet. The benefit to these solutions is that they can be the best to show off plants indoors. For small collections or displays, a single fish tank works exceptionally well. They hold water, are usually readily available in most cities, and tend to be cheap. Clouches in contrast are much more expensive. Proper terrariums can be pricey, but a fish tank can be modified using acrylic glue to put hinges and a plastic door on the top. Holes can be drilled to raise airflow, making this a more adjustable option.
Windowsills are another common location growers will utilize. Windows that are South or West facing work best in the Northern Hemisphere, barring any trees or other obstructions. Generally if your window gets 4-6 hours of direct sunlight and 4-6 more hours of indirect sunlight, it will be good to go for growing most species. There are some species like Drosera Adelae or Utricularia Calycafidia that prefer more shaded growing locations, requiring little direct light for healthy growth. The major problems with windowsill growing are heat and humidity. It's common to see people use bags, clouches, or make shift domes to trap more humidity. Little do they realize, they're raising the temperature if the plant is in direct sunlight. This can cook even the most heat loving plants during the hotter days of summer. Covering plants during winter in temperate areas is necessary as the humidity in most parts of the country drops much lower than most carnivorous plants will prefer. Humidifiers work well to help small collections to maintain good moisture levels and are available at most pharmacies and retailers.
Last, but certainly not least, growing indoors under grow lights. This is the best method for maintaining as much control over the growing conditions as possible. The trade off, you lose space in your home, this method is much more hands on, is much more expensive, and prone to catastrophic failures. If you have the space for a 2 foot by 4 foot space and adequate electrical capacity, you can easily have room for 512 plants in standard nursery trays and 2.5 inch pots. At the time of writing this, it costs around $500 to build a rack and stock it with pots, trays, medium, lights, and mylar wrapping to increase lighting efficiency. It's usually $20-40 a month in electrical costs, depending on heating and cooling needs, per rack. If you're in an area prone to power outages, then there's a chance your plants might die if you lose power during the winter due to no heating. The huge benefits to this approach outweigh the downsides. Being able to better prevent pests and diseases from reaching your plants will greatly increase their longevity. With consistent enough conditions, some species can grow impressive flowering displays or grow to larger sizes than seen outdoors in more variable conditions. This is the my most recommended route for a serious carnivorous plant grower. It becomes paramount to keep consistency in your growing space for long term consistent success.