Expert: Sarracenia Northwest - 5/6/2011

Question
QUESTION: Hey guys. I have a question about shade cloth. I have your video on growing these plants in the southwest. I have Venus Fly Traps and some sarricena. I'm looking at a product called aluminet. They are recommending 50-60% for the shading. Because of these plants needing 6 plus hours of direct light I don't want to block out to much. The lowest they offer is 30% then it goes 40-50-60 ect. What would you suggest. Thanks, Jason

ANSWER: The main thing to consider in your situation is moderating soil and leaf temperature.  So the purpose of the shade cloth is to reduce sun intensity that contributes to overheating of the plants.  There will always be a give-and-take when trying to control temperature, while still providing sufficient sunlight.  Since you have Volume 1, I'm going to assume that you're already growing your plants in terracotta pots.  

In our experiments, the terracotta pots kept soil temperature 15-20° below ambient temperature.  So the main issue is controlling leaf temperature.  With any non-desert plant, leaf temperature should be kept under 100°F.  If it's 100° in the shade, then you'll definitely need to sacrifice sunlight.  There's just no way around it.  I recommend using 50% shade cloth.  I've never used Aluminet because it's not necessary in my region.  But many growers who live in areas where the sun is quite intense have reported it to be very useful in controlling temperature.  

Position the shade cloth so that your plants are sheltered from the most intense sunlight.  Typically this will be from midday to mid afternoon.  Make sure the plants can get direct sun in the morning and late afternoon, about an hour or so before sunset.

Good growing!
Jacob Farin

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

QUESTION: Thanks Jacob for your responce. The plants are in plastic pots but I have them siting in ceramic glazed white pots to shield the main pots from the sun. There is also water in the pots about half way up.
Thanks, Jason

Answer
That could possibly work, but our experiments were specifically with terracotta because of the increased evaporation.  The evaporation is key to keeping the soil cool.  The terracotta pots should also be set in a small amount of water.  If the water level is too high, it'll heat up and be difficult to cool down.  Even with a shield, the extreme ambient temperature will still heat up the water, which in turn would keep the soil temperature the same as the water.  With warm soil and reduced evaporation, you will also have reduced aeration, which will contribute to increased soil breakdown and add another layer of potential complications. Again, we haven't experimented with the method you're using, so I can't say how effective this is even with the use of shade cloth.