Question
QUESTION: I have a Cape sundew that has been growing very well in my terrarium until about a month ago. It had some fungus so I decided to use some fungicide. Turns out the fungicide did more damage than the fungus. I originally had two but the poison burned the leaves of one of them so terribly it died. I know now not to make that mistake again. Now the one I have left is recovering. It has shrunk dramatically and I see flower stalks emerging, but they're too small to create flowers. I really wanted to see the sundew's beautiful blooms. The sundew has made a division though, and the plantlet is doing very well. I've been wanting to experiment growing strategies for the sundew so when the plantlet becomes larger, I'd like to place it in a bottle-terrarium, and acclimate it to my east facing windowsill. The window gets 4.5 hours of sunlight right now. Partially morning light and the rest being some weak afternoon light. Is this enough light to allow the plant to grow well?

ANSWER: Hi Faramarz,

First, lets make sure you have the right type of fungicide.  Use only sulfur-based fungicide or Neem oil.  All other types of fungicides are not appropriate for carnivorous plants, which will result in the symptoms you've described.  We use both sulfur and Neem fungicides on our plants, and we haven't had any problems with them.  So make sure you're using the correct type of fungicide for your plants.

Secondly, and I hate to tell you otherwise, but part of the problem you're experiencing is because of growing the plants in terrariums.  I'm not a big fan of terrariums because they tend to harbor fungus (as you've experienced) and it's very difficult to get the lighting correct.  

Drosera capensis likes very bright sunlight, almost full sun.  But it doesn't like warm temperatures.  So it's always difficult to give this plant the type of lighting it wants without baking it in the terrarium.  You're then left with two options, grow the plant in sub-optimal lighting or remove the plant from the terrarium.  

If you choose sub-optimal lighting, the plant weakens over time and becomes prone to fungus.

Of course, I favor removing the plant from the terrarium.  This species will adapt to lower humidity, as it is lighting, NOT humidity, that creates the dew on its leaves.

I grow many types of sundews in my windowsill, and I do so without a terrarium.  So you might have better results if you simply ditch the terrarium and focus on providing more light for your plant.

Here are a couple links you should check out:
http://www.cobraplant.com/gallery/Humidity/humidity.html
http://www.cobraplant.com/caresheets

This should give you some idea about how carnivorous plants can grow without a terrarium.

Good growing!
Jacob Farin

---------- FOLLOW-UP ----------

QUESTION: Since the fungus, I've changed the sundew's environment. Humidity from 70-80% down to 40-50% and lights on for 15 hours rather than 13. The plant is much more robust even though it just started recovering: The petioles are stiffer and the leaves aren't droopy. They don't have their red color though, because the light spectrum I use causes the dews to lose their pigment, but that's all. I'm planning to put the baby sundew in the bottle terrarium at first so that it'll be comfy. Then I'll start accustoming it to the lower humidity by making the hole at the top of the terrarium bigger and bigger until there is no more use of it. Would this be just fine? I believe this would help to reduce or prevent shock on the plant. And would the plant do alright in the summer as I live in Phoenix and nearly half of the year the high temperatures reach into the 100's or high/mid 90's.

Answer
It might be easier to let the plant grow in lower humidity from the beginning.  This will eliminate the need to acclimate your plant when you remove it from the terrarium.  As long as the soil is constantly moist, the humidity near the plant will be enough to keep it happy.

Grow the sundew in a sunny windowsill.  In your case, select an east window.  Cape sundews grow best when the temperature is below 80癋.  They're a mountain plant, so they prefer cooler temperatures, but lots of sunlight.

Good growing!
Jacob Farin