Sundew Recovery Guides
Is your sundew struggling? Does it have insect problems, mold, or fungus problems? If so, you've come to the right place ;) This page is basically a solutions manual that can help you identify what problem you have and can hopefully help you solve the problem and allow your sundews to recover again. *Note*- this guide does not cover tuberous or petiolaris sundews, since they deserve their own category.Have a question not covered here? Shoot me an email and I'll add it to this list.
My Sundew doesn't have any dew on it!
Dew is important for sundews because it allows them to catch insects, which in turn allows them to grow faster (and healthier) and flower. There are several factors play a role in dew (mucilage) production, including light, temperature, humidity, and air movement. Each can drastically effect the amount of mucilage produced. These variables are dependent on one another, as you will discover below---
Light is possibly the single most important factor in dew production. If a sundew does not receive enough light, it will appear completely green and the tentacles will have no coloration in them (normally the tentacles will turn pink or red in bright light. The dew during this time will usually only be produced in high humidity, and will be mostly water (without the sticky substance). If given more sunlight, sundews have the energy they need to produce a thicker mucilage that is more capable of holding onto insects, and will not completely evaporate in low humidity. I'll eventually provide a more scientific explanation ;)
However, if growing outdoors, bright light normally causes higher transpiration losses, which can end up causing your sundew to produce little or no dew during the hottest, brightest part of the day. If this is the case, you will either have to more your sundews to a shadier location. If growing under lights indoors, you can combat transpirative losses by moving the fixtures further above the plants, or by reducing temperatures or increasing humidity.
Temperature can effect dew production because sundews can decrease or increase the amount of water they pump out through the tentacles depending on how much temperature stress there is. Higher temperatures increase transpiration (water loss), which causes the dew to evaporate more quickly. This is important for certain sundews like D. schizandra and the other Queensland sundews (D. adelae and D. prolifera), which prefer cooler temperatures coupled with higher humidity in order to produce the largest amounts of dew.
Humidity is known to provide "superficial dew" that will disappear if the plant is removed from its humid environment. Humidity is important because it decreases transpiration/ water loss, allowing dew droplets to be larger. While humidity is not as important if there is no air movement, humidity can be very beneficial in higher temperatures, bright sunlight, or when there is a lot of wind. Humidity can be increased by using a small humidifier or the tray method (which is what I use).
Air movement is generally encouraged by most sundew growers, but I've found that when growing my Drosera under T-12 and T-8 fixtures with the tray method, they sundews do amazingly well with stagnant air conditions. Air movement is usually needed when temperatures are higher, because it increases the amount of evaporative cooling that takes place. However, air movement also leads to higher transpiration rates, which decreases the amount of dew unless higher humidity is provided. The room I grow my sundews in doesn't even have a vent in it, so there is never any air movement. Even though temperatures are nomally 85-90 degrees F, my South American and other common sundews do suprisingly well and have tons of dew during the summer months because there is so little air movement, and the humidity is high enough from using the tray method.
As you can see, each variable can influence the rate of transpiration, and the other factors can be increased or decreased accordingly to encourage the smallest amount of transpiration, which in turn increases the size of mucilage produced. If you have any additional questions, or nothing seems to be working, shoot me an email.
Sundew Leaf Deformation
There are many potential reasons why the leaves on your sundew may become deformed. Most of the time, it is due to environmental problems, but it can also be caused from insects, like aphids. Other times, leaf deformation can be caused by humic acids, found in peat moss (explained in the paragraph below).
The leaves on my sundew are small and deformed, and there is a black substance at the crown of the plant. What do I do?
"The darkening of the growth point, as shown by the photograph [below], is caused by humic acids, and perhaps other solubles, wicking up and depositing themselves, first on the hairs and stipules of the leaf primordia, eventually covering the entire surface of the growth point and leaf primordia. My experience is that this can have a damaging effect on the growing point and can supress new growth. The easiest way to reduce this is to gently provide overhead watering with warm, purified water as often as necessary to reduce this precipitate. Another solution would be to use less peat moss, since it is a strong source for the most offending compounds, though other media ingredients may also be sources. It is also affected by temperature, ambient humidity, air movement, etc."
This substance will also wipe off, if you rub the affected area with a moist cloth. If no action is taken, many of the leaves will become deformed. The preceding quote was found at this page: http://terraforums.com/forums/showthread.php?t=106361&highlight=water
What does "Acclimating" or "Hardening" a Sundew Mean?
Acclimation is the gradual adjustment of a plant to new conditions.
The Webster Definition of acclimate is: " to adapt to a new temperature, altitude, climate, environment, or situation" [http://www.merriam-webster.com/dictionary/acclimate]
Acclimating a sundew to lower humidity
This means that if you buy a sundew from Lowes (either a D. capensis or D. adelae most of the time), in order to take the sundew out of the cube, you will have to gradually expose the sundew to lower humidity by slowly sliding the lid off of the cube until it is finally removed after a week to 2 weeks. The dew droplets will likely be smaller than when the sundew was grown exclusively inside of the cube (due to the reasons described above)
Above Left- Drosera adelae (purchased from Lowes) fully dewed inside of its cube
Above Right- A different D. adelae plant, after an acclimation period of 2 weeks (notice the smaller dew droplets.
Acclimating a Sundew to Brighter Light
Many new sundew growers report that their sundews' leaves burn up or turn brown when the bring them outside for the first time. Considering ample water was provided, this generally means that the light intensity (and heat as well) was too much for the sundew to handle. This is what I normally advise:
1. Grow the plant in a shady location for a week or two (to ensure that the plant is able to adjust to the conditions outdoors first)
2. Move the sundew to a partly sunny location for several weeks until it has colored up and appears to be established.
3. Be very observant of how the sundew adjusts- if the plant looked fine in the shady locaiton, but appears to be stressed in part sun, consider moving it back and letting the sundew acclimate there for a longer period of time. If the sundew is stressed the second time when bringing it back to a partly sunny location, consider permanently growing it in the shade. (The same applies for acclimating a plant from part sun to full sun).
You may notice that sundews grown in brighter light no longer need as much humidity to produce large dew droplets (but this is not always the case, and varies from time to time).
Below- compare the same Drosera adelae plant (before and after acclimation to a brighter location)
Acclimating a Sundew to Warmer temperatures
Acclimation to warmer temperatures follows the same basic technique as the other forms of acclimation. If you want to move your sundews outdoors in the heat (in Singapore, for example), but you've been growing them in air conditioning for a long time before that, then do the following:
1. Move the sundews into the location you plan to grow them in (considering light acclimation as well) and leave them there for a half hour. If they look ok, then leave them for an hour.
2. Take them back indoors and let them recover (may not be necessary if conditions are favorable outdoors)
3. The next day, place them outside for 2 hours (or however long before they begin to show signs of stress).
4. Repeat step 2.
5. Gradually increase the time you leave them outdoors until they can be left outside all day long without showing any serious signs of stress. The sundews will inevitably be more stressed outdoors than in air conditining indoors, but the stress I'm describing is more severe- such as complete loss of dew coupled with minor wilting even when there is plenty of water in the pot or tray.
Additional Questions or Suggestions?
Contact me at: sundewman(at)yahoo.com