Backyard Ponding Part 2: Bog Filtration

Part 2: build DIY bog filter

Bog filtration is another way to keep your water clean in your water feature that does not require and expensive filtration system. I know it sounds really complicated and scientific but the science behind it is really simple. Bog filtration is natures way of removing algae and excess nutrients as well as debris from the pond. Simply, the plant roots and the pea gravel catch all the bad stuff and clean the water. Bog plants are plants that loves water ( http://hoskingnursery.com/hardy_plants.html) FYI not an advertisement but a good list of bog plants.  The cool thing about bog planting for me is that it combines my love of gardening with a functional and cheap filter for a small pond. There are many beautiful plants and blooms many people have not heard of because they require "wet feet".  Plants such as water lettuce, duckweed, water hyacinth, yellow iris, water lilies and some types of canna work great as bog plants.

Steps to a simple bog filtration:

Step 1: Pick a container that will allow the circulating water to drain through it.  I also had this big plastic drum left over from a previous project. I cut the bottom 1/4 of the drum and left it open.  I then used the cut portion as the planting container. (see below)

barrel with bottom cut off

 

the bottom turned upside down as "planter"

Step 2:  Drill holes in the bottom of the planter portion (above).  These holes need to be big enough for water to flow through easily, however,  small enough to not let the pea gravel at the bottom seep through the holes.

Step 3: Make the medium for the plants to sit in.  For my bog I poured a bag of pea gravel at the bottom of the planter. Then in a separate container I mixed top soil and sand (probably more sand then dirt). I found the dirt tends to rise to the surface. At this point, you can also add some pond fertilizer to the mix. Place your plants in the container.

place plants in it...water lettuce and purple pickeler

Step 4: Make the leftover barrel useful by adding another filtration system similar to the rain barrel system (see part 1)  The nursery pot holding the filter medium(below) will sit inside this barrel giving further place for filtration.

use plastic porch screen to catch large debris

      a) attach screen to barrel by using the original lid to tighten the screen in place.
      b) Find another nursery pot that fits in the barrel snugly. Drill holes in the bottom 4 inches.

tip: drill holes with dremmel or wood burner tip

      c) find some medium again that will catch debris and create biofilters like plastic screen, bath scrunchies and I even read cut up milk jugs. The more nooks and crannies on the medium the better...it provides a more suitable surface for bio to attach. The layers are the same. pea gravel, plastic and then batting.  All of the medium can be replaced cheaply and easily. However, you should not do it at all at once since your goal is to set up a little ecosystem. You need the bacteria that is going to grow on these surfaces.

screen, bath scrunchy, batting. it does not need to be fancy

pea gravel

plastic medium scrunched up

batting on top

       d) cover top with hardware screen or galvanized screen. (below)  Place nursery pot in the pond and barrel over the pot. Place your planting container on the barrel. Make sure it is dry otherwise it is way too heavy to lift. VOILA!

galvanized wire

put it all together and wet it

Step 5:  Get the water from the pump to the bog.  This can be done many ways.  I simply redirected  my flexible plastic 1/2 inch tube by using a plastic splitter (found in any hardware store that sells sprinkler adapters).  One side can go to your bog and the other to another filter (ie like my rain barrel filter).  You can insert it either under the pea gravel or on top. In my pond, I had this cheap waterfall I had bought at Lowes and hated to waste it. So, I placed it with the pond liner in the soil so the water comes up the 1/2 inch tube and into the waterfall container. The waterfall container dumps the water into the planter.  Roots catch the debris and excess nutrients, drains through the gravel and into the nursery pot with the plastic and batting and ultimately back into the pond. whew!!!!                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 

cutting the pond liner to put into barrel

 Now, Part 2 is complete and we are ready for my final phase of this pond...The decorating!  I am planning an elaborate fairy garden all with miniature chairs and moss grass.  This will be Part 3 of my backyard ponding blog.

Happy Gardening!
Nicki