An unusual intersection of issues came to me last week and their answers led me to this blog. A neighbor got new carpet that’s a priority over the big clay pots that used to go inside each winter. A reader asked if it is possible to make a rooting chamber without a mist system. The answer to the first dilemma is to provide shelter outdoors for the big pots and propagate them so the small plants can live indoors more easily. And yes, it is possible to fashion an enclosed propagation box that has no mist system. While some plants are difficult to root without mist, many green stemmed (herbaceous) and woody cuttings will root in a humid chamber.
I have built several different sorts of these boxes, most in congregate settings indoors, but have never been satisfied. With some research and a bit of tinkering for size and soil capacity, I’ve come up with some ideas that will work for both gardeners and me, too. I hope you will try this simple idea, make it your own, and let me know how it goes.
Here are the things you will need and how they work together to create a rooting chamber.
- Clear Plastic Box. A propagation chamber needs to be tall and deep enough to accommodate the cutting and the rooting medium. You need at least an inch of rooting media below the base of the cuttings and another above their top. That means if you take a six inch cutting and want to put 3 inches of stem into the media and 3 above it, the clear plastic box must be at least 8 inches from base to lid inside. My friend with the tropical plants to root may need that size, but smaller cuttings can be rooted in a clear plastic shoe box. Large or small, the box and its top need to be clear plastic to capture the full spectrum of light, to make cleaning more efficient, and often for the cool opportunity to see roots growing.
- Soilless Rooting Mix. The preferred rooting medium for this enclosed system is soilless, a combination of peat and perlite in equal portions. Individual elements and prepared mixes are both readily available. As with any peat/perlite product, it is important to wet the product to reduce its dustiness and get it wet enough to start the cuttings on their way.
- Rooting Hormone. I like to set the rooting box on a larger tray to make a space to prepare cuttings. That gives me a place to put the plants, a paper plate with Hormex Rooting Powder on it or a cup of Hormex Liquid Concentrate. It is essential for success to stick cuttings in one motion and the setup allows me to do that. Make a fresh cut on the stem, apply the rooting hormone, and slip the cutting into the mix in the box.
- Watering System. Cuttings must have adequate water to keep the process going, and it can be tricky to keep conditions moderated. Overwatered cuttings can rot and fungus can grow on saturated soil in this warm, humid environment. Dry cuttings and media are just about useless; the plant material is even harder to rehydrate than the soilless mix. It’s nerve racking to water the soil in a box like this from the top with a small nozzle. The answer is a reservoir or other way to get water into the soil consistently without disturbing the cuttings or flooding the soil. I have used rolled up wick material like that used by African violet fanciers and sponges formed into a rolls at the corners of the box. But I like the small clay pot waterer best of all I have tried. Prepare a small clay pot by sealing its drain hole. I used bathtub caulk this time because it was handy but any kind of sealant will do. This is a good project for a recycled pot, since a new one will need to be sanded lightly to break up any coating that may have been applied to it.
Assemble these items, grab a bucket, a trowel, and some water. It’s wise to don a dust mask before pouring the fresh rooting mix into the bucket. Add water to the dry mix slowly and mix as you go with the trowel until the mix is evenly damp. Position the clay pot at the center of the plastic box and fill in around it with moist mix. A dot of fresh caulk on the already-closed drain hole will hold the pot in place nicely. Dip the base of each cutting into undiluted Hormex Liquid Concentrate or roll it in Hormex Rooting Powder, depending on the type of cutting and your preference. (Click here to see what strength powder to use if you are unsure.) Fill the pot with water. If your tap water has issues such as high pH or mineral content, sediment, or other contaminates, use distilled water or boil the tap water and cool to room temperature before using it. Replace the water as it is absorbed into the mix and occasionally add 2 drops of HLC to provide nutrients and a boost to the rooting process. Keep the top on the box and watch for condensation to build up inside. Open the box to vent it – you don’t want to create enough moisture to drip. I just lay the top sideways for a few hours to let fresh air in or you can prop it open with a chopstick or something similar. Keep the entire setup in the shade and check for signs of rooting like new leaves or white roots that you can see through the clear box. Should neither happen, gently tug on the cutting. If it is dark at the soil surface and comes right out, toss it. If it resists, it is rooting and you can relax.