A few months back I grabbed an armful of juniper branches from the green recycling bin at a Bay Island Bonsai workshop. I’d found both kishu and itoigawa shimapku branches and figured I could use them to make cuttings for grafting roots or branches. Although I’d made cuttings many times before, I wasn’t sure about what soil worked best to facilitate rooting or how long to leave new cuttings in the greenhouse before bringing them outside. An experiment was in order.
I tested three different soil mixes outside and in a greenhouse. Despite poor experimental design and uneven care after the cuttings were made, I was surprised to find fairly consistent results. I planted the cuttings in “houseplant soil” (an all-purpose soil mix rich in organic ingredients), perlite, and a mix of perlite and sand. The perlite yielded better results than the houseplant mix, and the sand and perlite mixture yielded better results than perlite alone. Overall, the cuttings I left outside fared better than those left in the greenhouse, but I suspect that’s mostly because the cuttings I left in the greenhouse were watered erratically. Here are some photos of the cuttings after a few months.
“Houseplant soil” (greenhouse) :: perlite (greenhouse)
“Houseplant soil” (greenhouse) :: “Houseplant soil” (outside)
Perlite and sand (greenhouse) :: “Houseplant soil” (outside)
The cuttings planted in perlite and sand fared equally well indoors and out. I wasn’t too surprised by this as Boon Manakitivipart and others recommended this mix and it offers a good balance of drainage and moisture retention. It’s also a sterile mix, unlike the “houseplant” mix I used. Why did I try the houseplant mix? Mostly out of curiosity. And why did I use cell packs instead of larger containers? Simply to save the time of wiring screens into more pots. I’ll repot all of the viable cuttings into bonsai soil this coming winter.
Last year’s cuttings
I shared this story less to encourage the use of perlite and sand than to encourage any amount of research on the topic. Many people are experts at this – are you one of them? If anyone knows of good resources about making cuttings, feel free to share. I used rooting hormone for all of the cuttings and made clean, slanted cuts with a grafting knife. I also planted all of the cuttings at an angle. Are there better approaches to preparing and planting the cuttings? I experimented with small, medium, and large sized cuttings and found that all lived, but there may be good reasons to start larger or smaller cuttings. Any suggestions?
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