There are several possible causes that the trap of a Dionaea muscipula or "Venus Flytrap" won't close:
- It's not getting enough sunlight
- It's not getting enough water
- Watered with the wrong type of water
- Planted on the wrong soil
- It has been overfed
- The snap traps have been triggered too often
Probably the biggest reason why your Venus Flytrap doesn't close anymore is that it doesn't have the energy to do so. If the snap traps won't close or have a very slow closing speed, it could be because of one of the following reasons.
1. It's Not Getting Enough Sunlight
The sun is the main source of energy for a lot of plants, including the Venus Flytrap. It gives the plant the energy it needs to photosynthesize. During this process, cells of the plant use carbon dioxide and the energy from the sun to make sugar molecules and oxygen. This will help maintain a healthy plant, which will naturally close whenever the hairs of the leaf are triggered.
Therefore, you want to make sure that the plant gets enough sunlight. Many people like to grow these plants indoors on a windowsill, but they actually grow better outdoors. On a patio or a balcony, somewhere that they will get at least 6-10 hours of direct sunlight per day.
When a Venus Flytrap does not get the right amount of sunlight, it wil not have the energy to close its traps.
2. It's Not Getting Enough Water
Venus Flytraps love water and can not tolerate drying out. They need water to survive and to maintain good strength and energy. Water helps the plant by transporting dissolved sugar and other nutrients through the plant. Without enough water, the plant will collapse.
Closing the traps flytrap costs energy. When it doesn't get the right amount of water, it will not have the right amount of energy to close its traps.
The best way to provide a Venus Flytrap with the right amount of water is to use the tray-method so that the plant is wet at all times.
For the tray-method you need:
- A tray (or bowl/plate) at least 1 inch (2,5 cm) deep
- Mineral Free water
- A plant pot with holes in the bottom
To use this method, take a tray, a bowl or a deep plate, fill it with approximately ⅖ inch (1 cm) of water, and put your Venus Flytrap, WITH pot and soil, on the water. Make sure that there is always enough water in the tray, this way the plants will always have the right amount of water.
3. Watered With The Wrong Type Of Water
In order for the snap traps of the Venus Flytrap to close properly, it is of great importance that it receives the right type of water. Because the flytrap naturally lives in nutrient-poor soils, giving a Venus Flytrap water that contains too many minerals can "over-fertilize" and "burnout" the plant. The build-up of minerals in the soil and plant will eventually kill the plant.
When the plant has been watered with the wrong type of water over and over, the plant will get over-fertilized, burned out, and will not have the energy to close anymore.
So, what water is safe to use with a Venus Flytrap?
The only water that you want to use is MINERAL FREE water or water with less than 50 TDS (total dissolved solids). You can buy a TDS-meter here on amazon to measure how much total dissolved solids there are in the water.
The following kinds of water are safe to use: water from a Zerowater water filter, rainwater, distilled water, and water from a reverse osmosis system.
4. Planted On The Wrong Soil
Planting a Venus Flytrap on soil with fertilizer will damage the plant. The mineral build-up is toxic for the plant. Using the wrong soil will hurt the plant and can be the reason why its traps are not closing anymore.
When it comes to planting carnivorous plants there are often misconceptions of what is good and what is not good for the plant.
Which soil mix is best for a Venus Flytrap?
Actually, these plants grow naturally on Sphagnum Peat moss, so this will be the base mix of the soil. Peat moss is dead fibrous material that forms when mosses and other living material decompose in peat bogs.
Because the plant will be poted, it's good to have some extra drainage in there. This can be accomplished by adding some perlite, pumice, washed sand, or silica sand.
The best mix for a Venus Flytrap is 1 part sphagnum peat moss and 1 part perlite (you can also use 1 part of pumice, washed sand, or silica sand instead of perlite).
Sphagnum Peat Moss
5. It Has Been Overfed
By feeding, I mean putting a fly in the snap trap of a Venus Flytrap and letting it digest the prey. Feeding the plant an insect per week or so is actually not harmful, despite it is not necessary to give the plant insects because it will catch its own.
Whether a plant is able to digest 1 or 10 insects per week depends on a lot of factors. If the plant is strong and healthy, it will have enough energy to digest more insects. Remember that giving the plant the right amount of sunlight, the right soil, and the right amount of water also plays a big role in the amount of energy it has.
Feeding a weak or unhealthy Venus Flytrap too many insects can work counterproductive. There will be a big chance that the traps won't close or open because the plant will simply not have the energy to do so.
While there is a big debate going on about if overfeeding a VFT is possible or not, it's best not to explore the plants' limits.
6. Snap Traps Have Been Triggered Too Often
Most snap traps can be triggered 10-12 times before they turn into photosynthesis leaves and eventually die and fall off. Then the plant will produce a new trap from its underground stems.
No matter how the traps got triggered, by finger or by insect – when the trap has reached its closing and opening limit, it will die, and not open again.
But, don't worry..
Only the snap traps will die, the life span of the stem of the plant has been estimated to live up to 20 years and longer. Besides, even when the plant is held in perfect conditions and is healthy, the snap traps will still die after 10-12 times of closing and opening.
When winter comes around, the Venus Flytrap goes to sleep, just like trees do.
There is less sunlight, which means the plant will have less energy will grow at a slower rate. It's also cold in the winter, which means there are fewer insects to catch.
Because of these seasonal changes, the plant will receive less energy and nutrients in the winter. The plant has to preserve energy to stay alive, which it does by letting fall of all snap traps. But before the trap leaves fall off, there is a big chance that the trap will not close.
Venus Flytraps don't necessarily need to go dormant, they can grow well inside under artificial lights at all times.
However, letting the plant go dormant in the winter might be healthier for the plant because it mimics the natural environment of the plant.
BONUS: Why Won't Your Venus Flytrap Open
Here is a quick list of possible causes that the trap of a Dionaea muscipula or "Venus Flytrap" won't open. Keep in mind that it can be more than one of these causes combined that are causing the plant not to open anymore.
- There is an insect in the trap
You just have to wait patiently until the trap reopens (time for digesting is between 5-12 days, depending on how big the insect is that it has caught)
- The insect that it has caught is too big for the trap
If the snap trap remains half-open while digesting an insect, there is a big chance that the trap will go black and fall off. Because the trap is not sealed, bacteria can enter the snap trap infecting it and making it rot
- The plant is dying
This can be the cause of many things going wrong (Root rot? Funges? Bad soil? Wrong kind of water? Not enough light?)
During the cold season, this plant goes dormant (in the winter)