Yes, you can purchase propagators that will cost you a fortune, but after learning about this cool tool while earning my Propagation Specialist Designation from the Texas Master Gardeners this is the only propagator I use. It's easy to assemble and works brilliantly. Let me take you through the ten easy steps with photos:
1. Assemble the materials. You'll need a shallow, plastic pan, a small clay pot (with the drainage hole plugged) and commercial potting mix. The clear plastic tray isn't necessary, but I find it helps contain the mess (this is a top that covers trays of take our sandwiches).
2. Fill the shallow pan to within 1" of the top with pre-moistened potting soil. No matter how beautiful the soil in your garden is, it's important to use clean, sterile soil to avoid introducing disease to the cuttings. The plastic 4 cup measure was purchased at the dollar store (it makes quick work of scooping out large amounts of potting soil).
3. Plug the drain hole in the clay pot. I find hot glue to be very durable, but I've used bubble gum in a pinch. This will be the water reservoir that will slowly leak water into the surrounding potting soil. I've often been asked if a cracked clay pot will work but it won't because the water releases too quickly.
4. Center the clay pot in the pan and with a twisting motion sink it almost to the top of the soil (you want the rim to be slightly above the soil line).
5. Fill the clay pot with water.
6. Take cuttings of the plants you want to propagate. The best length is 4-6" with at least two nodes (the bumps on the stem).
7. Trim the cutting so that you have just enough plant material for photosynthesis, but not so much that the cutting will lose too much water. Start by cutting just below the bottom node, then remove all but two leaves from the top (pinch out the growing tip). If the plant is flowering, remove the flowers. If the leaves are very large, cut them in half. It's going to look pretty sad, but don't worry, when it begins actively growing it will grow back leaves.
8. Dip the end of the cutting into hormone powder.
9. Using a pencil, small stick (or my favorite is a metal nail that's used to help potatoes bake evenly), make a hole in the potting soil. Push it all the way down to the bottom so you can sink as much of the cutting as possible in the soil.
10. "Stick" as many cuttings as you can in the Self Watering Propagator. If this is an unfamiliar plant, be sure to label the cuttings.
Place the cuttings in a shady place, and keep the water reservoir filled. When you see new growth, it's a good indication that roots are forming. Gently tug on the cuttings and if you meet resistance, you can scoop out the new little plant and pot it up into a 4" pot. When the pot is filled with roots it's time to plant it in the garden.
I keep several propagators outside all summer long. When cold weather threatens, I fill several with tender plants and bring them inside under lights (cold tolerant plants can remain outside all winter long). In the spring, take the time to put the old soil in the compost heap and re-fill the propagator with clean potting soil.
That's it! Creating a propagator and keeping it ready to go will encourage you to "stick" those cuttings that are the result of pruning (or your dog running through the flower bed). Before you know it, you'll be bringing your pruners to your friends gardens and begging cuttings (don't worry, gardeners are a generous lot).