My first kokedama was a fern, and it died with its moss hanging off it in brown flaps by the second month. I had made every beginner mistake at once: too rich a soil, a plant that wanted more light than the corner gave it, and a watering habit that swung between bone dry and standing wet. I have made a good many since, and most of them have lived, so what follows is the method I actually use now rather than the one I first read about.
If you only want the short version of what a kokedama is and how to keep one ticking over, the kokedama overview covers it. This is the long, hands-on account of making one from scratch, with the parts nobody tells you until you have got mud to the elbows.
What a kokedama really is
Strip away the ceremony and a kokedama is a plant grown with its roots packed into a firm ball of soil, that ball then clad in living moss and bound with thread so it holds together without a pot. The name means moss ball. It grew out of the bonsai tradition, a relative of the potted moss-and-plant plantings called kusamono, and it shares a family likeness with the emersed moss mounds of wabi-kusa from the aquascaping world. What sets a kokedama apart is that the moss is not decoration on top of a pot. The moss is the container.
Choosing the plant first
The plant decides whether the thing lives, so I choose it before anything else. A kokedama offers roots a life that is cool, shaded and evenly damp, never dry and never baking, so the plant has to want that. Ferns are the obvious fit and the ones I reach for most: a small Boston fern, a hare's-foot fern, a button fern. Beyond ferns I have had good runs from pothos, peace lily, spider plant, asparagus fern and small-leaved ivies. What I no longer try are succulents and cacti, which need to dry right out between drinks and simply rot in a moss ball, and anything that grows big and heavy fast, because the wrapping cannot hold a lump straining to be a shrub. A small, slow, shade-tolerant plant is far easier to keep looking right than a vigorous one.
Size matters more than people expect. A plant whose root ball is bigger than a large orange makes an unwieldy sphere that is hard to wet through and heavy to hang. I keep mine to something I can cup in two hands.
The mix, and why the mix is everything
The soil is where I went wrong first, so I will be exact. A kokedama ball has to do two things at once that pull against each other: hold a firm shape for months, and stay evenly moist without going to sour mud. Ordinary potting compost does neither. It slumps when wet, sets like a brick when dry, and rots roots in between.
The classic Japanese mix leans on two ingredients. Akadama is a granular, clay-like volcanic soil sold for bonsai; it holds water in its grains and gives the ball body. Keto is a sticky black peat that acts as the glue. Getting proper keto outside Japan is fiddly, so the working mix I use, and the one most growers I know use, is roughly seven parts akadama or general bonsai soil to three parts of a peat or peat substitute for stickiness and moisture. I now use coir or a peat-free compost in place of sphagnum peat for that share, partly on principle and partly because it rewets more kindly; the reasoning is in peat and the peat-free question. If you cannot get akadama, a heavy loam-based soil with some added grit will bind well enough. The test is simple. Dampen the mix and squeeze a handful. It should hold together like modelling clay and keep the shape when you open your hand. If it crumbles, it needs more of the sticky part or more water; if it oozes, it is too wet to build with yet.
Which moss to wrap it in
Not every moss survives being wrapped round a ball and hung in a room, and this is the other place people come unstuck. What holds up best for me are the flat, carpet-forming pleurocarpous mosses, the ones sold loosely as sheet moss. A Hypnum, the plait moss, is the usual bag of sheet moss and it is ideal: it lifts away in coherent sheets, drapes over a curved surface and knits back down where it touches damp ground. Cushion mosses such as bun moss, Leucobryum, look wonderful as a dome but they do not like to be flattened round a sphere and tend to brown from the middle when forced to, so I use those in a terrarium instead and keep sheet moss for kokedama.
Whatever moss you use, rehydrate it first. I soak collected or dried sheet moss in a bucket of rainwater for a good hour, until it goes supple and deep green, then squeeze out the drips before wrapping. Dry, brittle moss will not mould to the ball and will not take. If you are gathering your own, do it thoughtfully and sparingly; the field manners are set out in collecting moss responsibly.
Building the ball, step by step
Here is the sequence I follow, ideally outdoors or over a big tray, because it is a wet and muddy job.
- Slide the plant out of its pot and gently tease away most of the loose compost, so you are left with the root ball and its finer roots. Do not scrub it bare; you want to keep the working roots intact.
- Take a good double handful of your dampened mix and press it around the roots, working it into a firm sphere in your palms as if making a large, dense snowball. Keep pressing until it feels solid and will not sag. A loose ball falls apart the first time you water it.
- Lay your squeezed-out sheet moss out flat, green side down on your hand or the bench, and set the ball on it. Bring the moss up and around, green side now facing out, until the whole sphere is clad with no bare soil showing. Patch any gaps with smaller offcuts.
- Holding it all together, start winding cotton or jute twine around the ball. Go in every direction, turning the ball as you wrap, crossing the threads into a cradle that pins the moss down all over. It looks untidy at first and then suddenly locks tight. Tie off firmly and tuck the loose ends under a wrap.
I use natural jute or cotton thread because it weathers to something you barely notice, and because if I want to keep the ball long term the moss eventually grips the soil on its own and the thread can rot away without mattering. Fishing line or dark cotton is stronger and more discreet if you prefer it to stay hidden. Give the finished ball a first long soak before it goes anywhere.
Watering by dunking, not pouring
You do not water a kokedama from a can. You dunk it. When the ball feels noticeably light in the hand, I sit it in a bowl or bucket of water, rainwater for choice, and hold it under until the bubbles stop rising, usually ten to twenty minutes. Then I lift it, let it drain fully, and only rehang it once it has stopped dripping. The weight in your hand is the gauge that never lies: heavy means watered, light means thirsty. In my centrally heated flat that works out at roughly twice a week in winter and more in summer, but rooms differ, so weigh rather than count days. Between soaks, if the air is dry, a mist over the moss keeps it green. There is more on reading a plant's thirst by feel in the note on watering moss.
Light, and indoors against outdoors
Bright but indirect light is the whole game. A spot near a window that never gets direct sun on the ball suits both the plant and the moss. Direct sun scorches the moss to straw and dries the ball faster than you can keep up with, and a radiator beneath it does the same. Outdoors in summer a kokedama is happy in full shade or dappled light, and it will actually keep better outside because the air is damper, but it must come in before frost, since a frozen ball kills the roots. I move mine out to a shaded, sheltered corner from late spring and bring them back to a cool windowsill for the winter.
Where it goes wrong
Almost every failure I have had, and every one I have been asked to diagnose, comes down to one of three things. The first is a ball left to dry hard: the moss shrinks, sheds and browns, and the plant sulks. The cure is to weigh it and soak before it gets light, and to give a dried-out ball a long, patient soak to rewet the core rather than a quick dip that only wets the surface. The second is the opposite, a ball kept sodden, standing in a saucer of water, which rots the roots from the inside and turns the soil sour; the cure is to always let it drain right out and never leave it sitting in water. The third is simply the wrong plant or the wrong spot, a sun-lover in a shady corner or a fast grower outpacing its ball, and there the honest fix is to unwrap and start again with a better choice.
Kept in that middle ground, damp but never wet, shaded but bright, a kokedama holds its looks for a year or two before the plant outgrows the sphere. When it does, there is no drama: cut the thread, lift the plant, pot it on or divide it, and build a fresh ball. That is the quiet rhythm of the thing, and once you have the mix and the dunking right it stops being fussy and becomes one of the most forgiving green things in the house.