This project takes a landscaping bush purchased at Lowes for $16.98 and starts its training as a bonsai specimen in what's known as a "training box" to start to make the roots the right shape for a more shallow pot. It involves building the box itself, pruning (with root pruning), and potting the tree.
This bonsai will be kept outside year round unless there is some extreme in weather. According to many I've spoken to about bonsai the most common mistake is to try to get a plant which is meant for outdoors to live inside. There are some tropical species which can tolerate this, but most evergreen and deciduous trees need humidity, lots of light, and seasonal weather changes which are nearly impossible to replicate indoors.
I wanted to plug a couple of sites which have helped me out considerably:
The Helpful Gardener - Bonsai Forum:
- Very good (free) forum which has always given me quick, well informed responses from cool people.
Wichita Bonsai Club
"The Rules of Bonsai" - A set of rules that everyone interested in bonsai should read.
Step 1: Materials
I plan to be relatively brief on the construction of the box itself, but I'll elaborate on the drainage and wiring aspects.
The materials used for the box were (mostly improvised):
A piece of poplar I had sitting around which was 9.5 inches wide by 5/8th's inches thick.
- this thickness was not necessary but only used as I had it lying around.
A long piece of pine which was 1 inch by 6 inches (which is actually 3/4ths inches x 5.5 inches)
A good belt sander (always important to try to cover my mistakes with)
A miter saw deep enough to cut a 5.5 inch width board.
A hand saw for the long cut at the base.
A drill press with a 3/4th inch hole boring bit.
An electric drill/screw driver with about ten 2.5 inch deck screws
A good pair of hand hedge clippers.
A little sand paper for hand sanding
For the potting itself:
Pea gravel purchased at Lowes for about $4.00
One gallon of all-purpose (open to debate) Bonsai soil purchased at a local nursery which specializes in bonsai for $6.50. It looks like it is mostly composted of akadama and peat.
Some of the mulchy soil removed from around the roots.
A piece of aluminum gutter guard mesh
18 gauge copper wire
Step 2: The Box
9 inches x 11 inches x 5.5 inches.
I made it this large in order to be on the conservative side due to lack of hands on experience and I'm happy with the size now that the project is complete. All bonsai don't have to fit into those tiny pots you associate with bonsai. Bonsai specialty nurseries have pots as large as 3'x1.5'x1' and larger in stock. I have also read that you don't have to be quite so careful about watering larger plants. Sounds good to me!
In terms of woodworking I did the long cut for the bottom piece with a hand saw (which turned out pretty terrible) and learned the value of a good belt sander to clean up the cut. The remainder of the cuts were done on my 10 inch miter (chop) saw. I put two 2.5 inch deck screws in between each board with six total on each side. Pilot holes help a lot with keeping the wood from splitting. For the drainage holes I used a 3/4ths inch wood bit in my drill press and cut through. In retrospect I may have put some smaller holes in the corners. Drainage is very important to bonsai and roots don't like to be drenched in water for too long a period or they can literally drown and rot. I decided not to put any kind of finish on it as I don't mind the fact that the wood absorbs water. Since then it has warped a little, but I don't mind it. I chose not to use treated lumber as I didn't want my plant exposed to the arsenic which they use. I used my belt sander to clean up all the uneven edges and smooth them out. I put on two feet as you can see in the picture in order to facilitate drainage.
Step 3: Drainage
Each piece of wire goes in a U shape through the top and is bent over on the sides to keep it in place.
Two more U shapes of longer wire go up from the bottom in order to wire the tree into the pot.
Drainage is also promoted by putting cleats (feet) on the bottom of the box so the holes will be suspended in the air.
Step 4: Pruning and Root Pruning
When I cut the pot away from the plant I teased as much dirt out of the roots as I could and tried to comb them out with my fingers. Traditionally a chopstick is used to weedle out as much dirt as possible. Shaking the plant also does wonders. Of course, try to put as little trauma on the roots as possible.
The picture shows something which I was very surprised by. The tree appears to have been potted deep in the pot with it's original root system almost becoming secondary. There was a large group of small fibrous roots (the kind you want for bonsai), then a small section of trunk, then what appear to be the roots from when the plant was in the ground. It looks like much of my work was done for me in terms of training the roots! I took a hacksaw and cut off the trunk at the base of the higher root system. I also pruned back a few of the longer/thicker roots which on the top half. I don't know if this root configuration a common thing with nursery plants, but it was ideal in this case.
Step 5: Potting in Layers and Wiring
Next cover the gravel with some bonsai dirt in order to get it completely covered. Place the tree in and cover the roots with more bonsai dirt. The wires should come up through the roots at this point so you can tie the tree down. You will want the base of the trunk itself out of the dirt so plan accordingly. Try to work some dirt into the spaces between the roots. Once the tree is in place pull the wires taut (check underneath to make sure they are as it can be tricky) then twist the ends together to be tight enough to hold the tree in place, but not putting much pressure on the roots or trunk. I just put the ends of the wires back down into the tree under the dirt. Fill the pot up with more dirt and water the plant. This will work some of the dirt into the root system. After watering top up the dirt and water again. The dirt is likely dried out so it will need a couple of waterings about ten minutes apart in order to really get it soaked. You can also immerse the whole box in water if you have that big a bucket available.
I took a little of the mulchy dirt from the original pot and put it over the top. I feel this will help with keeping the bonsai soil moist, but not soggy. I kept the mulch away from the base of the tree itself. (this step open for debate)
Step 6: Long Term Care
The tree doesn't need fertilizing if you just root pruned it for at least a month, but it is a good idea to use some fertilizer later on. Specialized bonsai fertilizers exist, but I have heard of people crushing up extended release tree spikes and sprinkling it on the top of the soil in order to have a little fertilizer leech in each time it's watered.
Ultimately this plant will be in a ceramic pot, but I will probably let it stay in this one for about a year to let it get use to it's new local.
Thanks for reading! If anyone has any suggestions please leave a comment.
Step 7: Constructive Criticism
1.) One source said that it has been largely disproven that using gravel on the bottom of the pot improves drainage as the water's surface tension keeps the water on the smaller particles above the pebbles. It is thought that a homogeneous (all particles approximately the same size) medium is best for air flow and drainage.
2.) The box easily could have been shallower. Especially if the pebble layer was removed.
3.) The box could use slats over the bottom (with more mesh) which would be much easier to construct and probably provide better drainage. The pot definitely could have more holes in the bottom especially in the corners.
4.) Bonsai "soil" rarely contains any actual soil at all but is rather composed of things such as peat or clay granules. Some options mentioned online include NAPA auto part #8822 or MVP Turface. There is a lot of debate online about soil. Most seem to agree that most of the medium should be some sort of inorganic aggregate. Google it and you'll find some opinions.
Step 8: Progress
These first 3 pictures were taken April 2nd, 2009.
This tree is now dormant after a summer where it lost most of it's leaves. It has been something of a learning experience and I thought I'd fill everyone in. It has set on buds so I am hopeful it will come back strong in the spring.
I re-potted it in late spring when, after more research, I realized the soil contained too many fine particles and therefore did not provide enough drainage. I have since used a soil which is composed primarily of a diatomaceous earth product which is sold at NAPA auto parts in 40# bags as a garage floor absorbent. I sift the material through a 1/8th inch sieve and add some bark of similar sizes. This has worked well for all of my other trees so far.
I will post more in the spring when/if it comes back in force in it's new soil.
The box/pot itself has warped a little with so much watering. Make sure to use plenty of screws to keep it together. I will probably change it to a new pot in the spring.
The tree has begun to put forth new buds and appears to have survived the winter. I re-potted it into a bonsai pot (pictures to be added soon). I have high hopes for it, but I may not let it flower too much this year in order to let it establish itself in the new pot more easily.
I have potted another nursery stock plant into the box (which split at the base and has undergone significant repairs). The new plant in the box is a bittersweet bush (some classify it as a vine).
By the way the nursery stock is just starting to come into big box stores like Lowes and Home Depot. I like to hunt through it early and find those interesting trunks.
Step 9: Spring 2010
The first flower opened today! I removed a number of buds to save the plants energy, but I will still let a few bloom. The picture says it all. I also have re-potted it into a fairly large pot. These pots are available at Lowes as the bottom half of an African Violet pot ("self watering"). I actually drilled holes in the bottom with an abrasive carbon steel drill which is designed for ceramic. Enjoy the pictures!