Nothing livens up a classroom windowsill like some predator / prey action. Carnivorous plants are the mightiest of houseplants, but many can only thrive in a soggy, acidic, bog environment.
To keep your carnivorous plants happy year-round, make them a simulated bog environment!
You can follow the steps in this Instructable to make a copy of the bog garden shown, or adapt the same techniques to whip up your own to suit your own containers and windowsill.
Let's get started!
Most nurseries and garden shops carry carnivorous plants packaged in small plastic terrariums (terraria?) to keep them moist. If you can't find any carnivorous plants for sale near you, try searching online for a supplier that will sell them by mail.
Here are some bog-loving carnivorous plants that you can grow in an indoor bog:
- Venus fly traps (Dionea muscipula)
- Pitcher plants (from the genus Sarracenia, Nepenthes, or others)
- Sundews (from the genus Drosera)
- Butterworts (Pinguicula vulgaris. I've never had any success with these, myself)
For more information about carnivorous plants, try:
- The book "The Savage Garden," by Peter D'Amato
- The United States Botanic Garden's website devoted to carnivorous plants
- The North Carolina Botanical Garden's website
Step 1: Supplies
To replicate a soggy, acidic bog garden, you'll need four containers:
- A large, waterproof tray for the bottom (this holds excess water and protects your windowsill from any drips)
- A large pot made of unglazed clay or "terra cotta" to hold the plants themselves. (It's important that water be able to seep through this container, as well as the next two on the list.) Choose a container that fits your site: I used a round pot, your location might be better served by, say, a "window box" trough, or some other container. Get creative!
- A small terra cotta pot to serve as a reservoir. This pot holds excess water and slowly lets it percolate into the soil, keeping the bog nice and damp. (For a tip on choosing the size of this container, see step 3.)
- A small terra cotta saucer to elevate the reservoir pot.
For the planter shown in this project, I used the following:
- A 10-inch-wide plastic tray (with no holes in the bottom)
- A clay pot, 8 inches wide and 4 inches deep.
- A small clay pot, 3 inches wide and 4 inches deep
- A small clay saucer, about 4 inches wide (which was sold to match the small clay pot above)
To assemble the planter, you'll need a sturdy, waterproof adhesive that can join ceramics together. I've had good results with both of the following:
- 100% silicone aquarium sealant (this adhesive smells a bit like vinegar at first, but is completely odorless once it solidifies)
- Expanding-foam glue (this glue forms a much stronger bond, but it will also swell to several times its original volume, which might not fit in with your plans)
To replicate a bog environment for the carnivorous plants, we'll be using a mixture of:
- 2 parts peat moss
- 1 part sand (play sand borrowed from the sandbox is perfect)
- 1 part sphagnum moss or "decorator's moss"
You'll need enough of this soil mixture to fill your large pot.
(Garden shops tend to only sell these materials in much larger quantities than you'll need for this project. However, every garden shop has a pile of broken, leaky bags somewhere. If you ask the shopkeepers very nicely, they'll usually let you have a small amount of this waste material for a reduced price. Better yet, get the most adorable second-grader you can find to do your asking for you; explain that it's for a school project, and you just might come out of this with some free dirt.)
Step 2: Make the Reservoir
Start by flipping the small, "reservoir" pot upside-down. Apply a bead of glue around the edge of the pot's bottom. Set the small saucer on top of the glued surface. Leave the pot and saucer together, bottom-to-bottom, until the glue dries.
Step 3: Test-fit the Pots
Once the saucer and reservoir pot are glued together, flip the pair over and place it (with the saucer-side down) inside the larger pot.
Check to make sure that the top edge of the reservoir pot sticks up above the top rim of the larger pot. This ensures that your reservoir pot can be filled with water without overflowing into the soil. (It's a good idea to try this "test fit" with your containers when you're choosing which to use for your project.)
Once you're satisfied with the fit, flip the reservoir/saucer pair over and apply glue around the edge of the saucer. Then, flip the pair over and press the glued saucer rim to bottom of the large pot. Wait until the glue dries.
Your pot assembly is complete!
Step 4: Populate Your Bog
Make Your Soil
Mix two parts peat moss, one part sand, and one part sphagnum (or decorator's) moss in a big bucket or similar container. Add water to the soil mixture until it's damp, but not muddy. Give it another good stir to make sure that the peat moss is soaking up the water. (This is the fun part.)
Place your three glued-together pots into the large plastic tray to contain any future messiness. Fill the outer portion of your bog garden with damp soil, but try to keep the soil out of the central reservoir pot.
Add Your Plants
Carefully remove your carnivorous plants from their original containers. (Growers often package carnivorous plants with little polystyrene "skirts" around the base of the plants to help keep the soil damp. I find it's best to use scissors to carefully snip these into several pieces, then gently pull them away from the plants.)
Take note of the soil that your carnivorous plants came potted in; growers often place carnivorous plants in pure peat or sphagnum moss. Notice how damp it was? Our goal in making the bog garden is to help the plants stay in soil that's this moist.
Make a small hole in your pot's soil for each plant, then carefully place it inside and tamp the soil down.
When all your plants are in the soil, use extra sphagnum (or decorator's) moss to cover the soil between the plants. The extra layer of moss on top will help keep the soil from drying out. (If you'd like, you could also use small pieces of moss you've collected from your sidewalk or the shady side of your school building.)
Fill the central reservoir with water, and add a little extra water to the plants themselves until you start to see a trickle of water coming out the bottom of the pots into the plastic tray.
To keep your plants soggy and happy, refill the reservoir whenever the water level drops.
All of the books suggest that you use rain water or distilled water for your bog plants; they don't like the minerals that are in tap water or bottled water. (I keep a jug of rain water next to the bog garden, just for this purpose.) However, if you have to choose between letting your plants dry out or watering them with tap water, go ahead and water your plants with whatever's available. They'll thank you for it.
Best of luck with your bog garden! If you have any advice, or a creative new design, please use the comments to share your ideas with the group!