First, you need to take a deep breath and not panic! If your Venus fly trap is turning black, it’s most likely going through completely normal processes.
The main reason a trap turns black and dies is that it’s simply at the end of its lifespan. Each individual trap on a plant has a lifespan of about three months during which it will catch about 1-4 insects.
As long as green new growth is replacing the dying traps, your plant is doing fine! However there are a number of other reasons why your Venus fly trap is turning black. Read on to find out what these causes may be, and their solutions!
It’s quite possible your plant is developing black traps if you fed every single trap on the plant. Yes, insects provide the nourishment that those traps seek, but closing every trap and digesting every single piece of food that’s inside those traps takes a huge amount of energy.
Traps may begin to die off to concentrate their remaining energy on photosynthesizing new growth. It’s also possible that the overload of nitrogen from too much food causes the traps to die. The solution to this is simply not hand-feeding your plant for about a month. Give it time to recover and maybe catch its own food.
When the new leaves are fully mature and open, you can resume feeding, but only 1-2 traps per plant once a week at the most. For more feeding advice, read my Venus fly trap food guide.
Eating something too big
In order to successfully digest its food, a Venus fly trap must seal both sides of its leaves together. Sometimes an insect with long legs or large wings gets caught in the trap. If these legs or wings stick outside of the trap, it cannot fully seal and may turn black and die as a result.
When feeding your plants, remember to keep the food 1/3 the size of the trap. Unfortunately, traps will sometimes bite off more than they can chew on their own. In this situation, leaving the plant alone is the best thing to do. Again, new growth will replace the dying trap.
Stress from moving or repotting
Did you get a new plant within the last month or few weeks? Did you also happen to put it into a new pot? If so, your plant simply need time to adjust to its new conditions. Traps dying on a newly repotted plant is normal, and essentially expected to happen.
To minimize potting stress, wait until the end of dormancy (February or March) before repotting. Even if it’s still in the same pot, being shipped in a box or even just a ride in the car from the nursery can be stressful for a plant. Time and good care is the best cure!
Venus fly traps along with most other carnivorous plants need nutrient-poor soil. The go-to options are usually pure peat moss or New Zealand long fiber sphagnum moss. The soil should be aerated with perlite or silicia sand.
These must have no fertilizers or nutrients added, or the plant may suffer mineral burn. If you’re using regular potting soil or something with additives, take your plant out immediately!
Soak it in distilled water while you go out and buy the right ingredients.
On the subject of water, your tap water likely has a higher concentration of Total Dissolved Solids (TDS) than what most carnivorous plants can take. If water has 50 ppm (parts per million) TDS or less, then it’s safe for carnivorous plants.
Most growers (myself included) need to buy gallons of distilled water for their plants. Saved rain water is also an excellent source for your plants. If you want, you can buy a TDS Meter to check your water sources. You may be one of the lucky ones that has nearly pure tap water! Yes, I’m jealous.
Your planter could also leech minerals into the soil and be the reason your Venus fly trap is turning black. Clay, terracotta, or un-glazed ceramic pots are highly discouraged for carnivores. Because they’re porous and made from organic materials, they will add minerals to your soil over time. This is a slow process that you can hold off if you regularly flush your pot with distilled water.
For the long term, you’ll want your plants in a plastic, foam or completely glazed ceramic pot.
No terrariums! Planters should be opaque. I like these pots a lot for adult plants, and also have a stack of these handy for seedlings and smaller plants. You can also find good ones at your local dollar or thrift store. Remember they must also have drainage holes in the bottom!
As cold weather approaches, Venus fly traps may start losing more of their leaves in preparation for dormancy. Dormancy is a completely natural process that is essential for Venus fly traps to survive.
When dormant, some plants may lose all of their traps or they could have a few remaining. There won’t be much new growth until the next spring, so the only solution is to wait until then.
Dormancy sucks for every grower, but it really makes you appreciate how stunning the plants are in the summer! Consider getting an easy tropical plant like a cape sundew to combat those dormancy blues!
Still have questions about your Venus flytrap or other carnivorous plants? Enter your email below for a free FAQ on growing carnivorous plants!
Thanks for reading, and I hope you found this information useful! Good luck with your Venus flytrap and I’ll see you in the next blog post!