Question
I want to grow Sarracenia purpuria outside and overwinter them. I will use a mixture of spagnum-based fibrous peat and river sand in a 3-1 ratio. I want to plant them in sunken containers into the ground. I will water with rain water and keep moist. What should the minimum depth of the substrate be and when is the best time to start? Any other species that would work with this setup as well? Anything else I need to know? Thanks!

Answer
Hi Charles,

This particular species is relatively easy to grow and is suitable for first-time growers.  For soil, I highly recommend using a mix consisting of 1 part peat moss and 1 part perlite.  The mix you've indicated doesn't allow for sufficient aeration, and you may have stunted growth as a result.  

If you want to use sand, still use the same proportions (1:1), but use only silica sand.  Not all sand is created equal, and some forms of sand leaches minerals into the soil.  You need sand that is inert, and silica sand is perfect for that.  So unless you know the composition of the river sand, avoid using it.  Use silica sand or perlite instead.

It's possible to use sunken containers, and there are two appropriate techniques to grow your plant in sunken containers.  The easiest of the two is to use a very large container, a minimum of 20 gallons with drain holes at the bottom.  The reason you need a large container is to dilute any compost or fertilizer that might seep in.  

The other technique is to use two containers.  One container should be non-draining.  The second container should have drain holes and be slightly smaller than the other container.  First sink the non-draining container into the ground. Next pot up your plant with the appropriate soil mix in the second container (the one with drain holes).  Set the pot plant into the larger container.  Add water and you're done.

Make sure you also choose a location where the plant can get 6 hours of direct sunlight.  

If you live in zone 7 or less, you may need to cover your plant with mulch.  The amount of mulch and the time to do it depends on your region.  

For more information about growing Sarracenia pitcher plants, read our care sheets online:
http://www.cobraplant.com/caresheets

Good growing!
Jacob Farin