From people who are not familiar with Drosera I almost always hear the same question: Do you feed the plants with flies? The answer is: sometimes.
In nature, plants live on soils that are very poor in nutrients and for this reason they have found other ways to get to nutrients. Under the artificial conditions in which the plants live in our homes, they usually get enough energy and nutrients through the substitution we use and the sunlight, so that feeding or the use of fertilizers is not absolutely necessary. "Not absolutely necessary" does not mean, however, that the plants grow worse when they are fed or fertilized. On the contrary! The effect is not really big and with a strong fertilization the plants will not be huge but they will die.
Drosera porrecta with prey
Feeding flies
At the beginning I wanted to feed my Drosera on the "natural" way. Ibought a pot of Drosphila melanogaster at an animal supermarket. These are little fruit flies and I bred the fruit flies, which wasn't that hard. If I wanted to feed the plants, I put the pot with the fruit flies in the fridge for about 10 minutes. The flies became very sluggish and I could then pour some into a second pot. I put the first pot back on the shelf and closed the second pot and put it in the freezer. After about 10 minutes I took the pot out again, moistened it with some drops of water and left it for about 30 minutes, so that the temperature of the dead flies couldt rise to room temperature again.
I tried to feed at least one fly to each plant with tweezers. That was a little bit tricky and I did this once a week and later once a month. That worked well at the beginning and it worked well but the more pots you have, the harder it gets. Now I have about 500 pots and it is clear that this procedure is no longer practicable.
The second reason why I don't feed them like this anymore are pictures from plants at their natural locations in Australia. There was a fly in almost every leaf of some upright growing species. I thought that a large Drosera palladia with maybe 100 leaves would not really grow much better if it caught 5 or 6 flies.
Feeding fish food
The next attempt to perform a practicable way of feeding my Drosera was with fish food. This is often reported on in the forums and I thought it would be useful. I have chosen a fish food that is made out of krill, a kind of shrimp with many proteins. I ground the food to a fine powder, mixed it with some water to a semi-liquid paste and then fed this paste with a disposable syringe to my plants.
That worked well and was easier than to feed flies, but in the end the problem was the same.
Fertilizers
I read in the GfP forum about the use of fertilizers. The discussion was very controversial. Some people said that they have been using fertilizers for years and some said that they kill the plants with them.
What finally convinced me to use fertilizers was the post of a member who professionally sells carnivores and who said that it is definitely alll right to use fertilizers. I started to fertilize with the recommended fertilizer called Wuxal. This is a NPK universal fertilizer 8-8-6 with trace nutrients. I use it in a dilution of 1:10 (1 ml in 10 l water instead of 10 ml in 10 l water) and the water consists of 1 l tap water and 9 l rainwater.
Watering is always done when the tubs in which the tuberous Drosera are standing are nearly dry and the fertilizer is applied every second time. This means watering 1 time with fertilizer and the next time without. I have been doing this for about 3 - 4 years now and I have to say that the plants did not die and in my opinion they are growing better than before.