Question
I have two questions.
Hello, I live in zone 10b and plant some sundews, venus flytraps and sarracenia in a large pot to have a mini bog garden. My question is how often do i have to repot it?

Since I live in such a warm climate do I need to do anything special with venus flytraps? I have heard that I may need to place them in my refrigerator for a couple of week, is that necessary?

Answer
The frequency of repotting really depends on several factors - the size of your bog garden, your watering method and your overall weather.  You mentioned a mini bog garden.  Would this be like a large bowl?  If so, you could potentially get away with repotting every other year as long as your summers aren't excessively warm and you're allowing water to drain through.  In most instances, it's not at all necessary to repot every year.  With large bog gardens, you only need to change the soil once every 5 years.

But the best way to determine if you should repot is to smell the soil.  Get some of the soil beneath the soil and smell.  If it smells foul or like rotten eggs, you got bacteria build up, which means it's time to repot.  If it smells like regular soil or has no odor, then you could get away with another season.  I do this frequently every spring since I have many plants to repot and I don't often have time to repot every one of them.

With your flytraps, it would totally depend on where you are for zone 10b.  Technically, you might get a light frost, which will help put your plant into dormancy, but I understand that it doesn't happen every year, especially if you're somewhere like San Diego or Miami.  Many growers have grown flytraps in zone 10b year after year without needing to place their plants in the fridge.  Others could have to get a new plant every year.  Again, it depends on your local weather system.  

The best thing to do is simply keep it outdoors throughout the year.  If the flytrap survives for more than a season, then you'll know that your particular microclimate in your region is good enough for the flytrap.  I know that this may not be the answer you were hoping for, but a lot of gardening has to do with understanding your microclimate and knowing what plants survives in it.  Even with the best of growing guides and following everything to the letter, plants can still die.  Even the fridge method has its risk.  

So if you're the adventurous type, keep it outdoors in winter.  Otherwise a couple months (yes, a couple months) in the fridge will make the plant think it's in North Carolina again.

For more information about growing North American carnivorous plants, watch Volume 1 of the Grow Carnivorous Plants DVD series.
http://www.cobraplant.com/DVD

Good growing!
Jacob Farin