Heater Bed

Winter in Finland can be quite cold with temperatures going down to minus 25-30°c. In the south of Finland where I live the temperature tends not to be so cold but can still easily be more than -15°c. These low temperatures mean that protecting the outdoor bonsai during this period can be a challenge.

I have a garage where I place the deciduous trees that will protect them from the frost and the cold wind, which is one of the main culprits for killing the tree because the wind can dehydrate the tree during this period of dormancy, but this does not protect them from the really cold temperatures. The garage already keeps the temperature a few degrees higher than the outside temperature and in general temperatures down to -10°c are ok but anything more than -10°c it is advisable to provide some extra protection. The garage has electric floor heating installed but this costs a fortune to keep on, as I found out to my horror last year when the electric bill arrived, so this year I thought I would build a small heater bed for the trees to sit on that I can put on when needed without costing a fortune.

The heater bed consists of a wooden frame with a thermal insulation base on top of which are two layers of sand. Sandwiched between the layers of sand is a heater cable attached to a metal grid.

The following photos show the step by step build of the heater bed.

Step 1. Wooden frame
A wooden frame was made as shown in the image below. The size of the frame was approx 120x60cm. The width of the frame matched the width of the thermal insulation material I would use. I attached a large sheet of plastic to the sides and bottom to help to retain the sand from falling through.

Step 2. Thermal insulation material
On top of the sheet of plastic I placed a piece of thermal insulation material. This material is about 4cm thick and very stiff. I could of used some type of board to form a firm base to hold the sand but this is what I had available and I thought it would help in maintaining some of the heat.

Step 3. Heating cable
The heating cable, which can be obtained from a local electrical shop, is specially designed to be used outside and for keeping things warm. Normal use of this cable is to warm water pipes, either the main water coming into a house or attached to drain pipes to prevent the water from freezing during the winter. The temperature output of the cable is approximately 10°c and uses 10 watts per metre. The length of cable I have used is 10m meaning that the power consumption is 100 watts. The cable is attached to a metal grid the size of the area with cable ties. I attached the cable on both sides of the metal grid at equal distances to try to get an even distribution of the heat. The cable is already fitted with a standard electrical plug as seen in the bottom of the image.

Step 4. Sand
The finished cable was taken out of the frame and a layer of sand approximately 2-3cm deep was added on top of the thermal insulation material. I then placed the cable on top of the sand and then proceeded to add more sand to cover the cable. I was not sure how much sand I needed so I started with another 2-3cm. The reason I wasn’t sure how much sand to add on top of cable was because I didn’t know how warm the sand would get when there was power to the cable. I wanted the sand to get warm but not to too warm and even though the temperature output was only 10°c the fact that I had looped the cable close together meant that the combined temperature could be more than that. As it turned out the difference between the ambient temperature and the temperature at the top of the sand was about 10°c. Because I am planning to use this heater bed only when the temperature is really cold the sand will never get above the magic temperature of +10°c, temperature that would start to represent that spring was here, so this difference is fine. If the temperature had been too high I would have simply added more sand to absorb more of the heat. In the image below you can see a thermostat to the left hand side. The thermostat takes the ambient temperature and a sensor, normally used to take the outside temperature, is inserted at the top of the sand to give some indication of the temperature of the sand.

Step 5. Placing the trees
We have been blessed that during November and the beginning of December the temperature had been quite warm for this time of year with temperatures even reaching +8°c on some days. But as can easily be the case here in Finland the winds change direction and we go from +2°c to –12°c overnight. This happen one night a couple of weeks ago and then that was the time to move the trees inside the garage and on to the heater bed. I didn’t actually turn the heater bed on because the garage was protecting the trees from the frost and the ambient temperature was only -6°c. Winter really started to come after this day with daily temperatures of –10°c to –16°c. During one of these days I turned on the heater bed as the temperature inside the garage was now –9°c. The out come was that the sand warmed to a nice temperature of +2°c. Perfect to keep the toes (roots) warm of my small collection of bonsai (potensai).

Cat litter as inorganic soil alternative

I mentioned earlier about my own bonsai soil mix. This isn’t as scientific as it first sounds. As many of you may already know bonsai enthusiasts throughout the world have been turning to cat litter (kissanhiekka) as an inorganic soil alternative to Akadama. Akadama is expensive and can be difficult to obtain here in Finland, often only available by mail order from another country. Cat litter is of course much cheaper and can be purchased from any supermarket. I have tested a couple of brands to establish if it retains its shape when wet and frozen and found that the brand ‘Rainbow Kevyt Kissanhiekka’ is the best cat litter that I have come across at the moment. I have used this cat litter for over a year for all my bonsai, indoor and outdoor, without any problems. The soil mix can be 100% cat litter if you require, but you can also mix it with other ingredients for specific tree types or to suit your own personal preferences. For example you can add some grit for a drier mix used on pines, junipers etc. or some pine bark to retain more water.

When using any material for bonsai soils it is important to remove the small particles and this is also the case with the cat litter. I have found with the brand that I am using that the largest particles are ok and remain in my mix but I sieve out the smaller particles less than 2mm. These small particles are not needed in the mix, as they will not allow the water to run through as easy.

My own bonsai soil mix has been made up of roughly 50% cat litter and 50% pine bark. The pine bark is also purchased from any local garden centre and then I run this through an old food processor to cut into smaller pieces. Again, as with the cat litter, I sieve out the smaller pieces and this time also remove the larger pieces that are bigger than 5-6mm. This bonsai soil mix I have used especially on my indoor bonsai because it helps to extend the time between watering that can be problem if using 100% cat litter.

Two of the most important tasks that need to be performed correctly for your bonsai to grow, watering and feeding, have been made easier by using cat litter.

Watering

Watering of my bonsai was a job that was a little difficult to understand in the beginning with questions like How often should I water? and What different watering schedules are needed for different trees? All this is now history when using cat litter. If required I could water my bonsai everyday, this can easy be the case in the summer, without any problems because any excess water not retained by the cat litter simply runs out the holes in the bottom of the pot or container.

Feeding

The use of cat litter has also changed how I feed my bonsai. As with the watering I was constantly reading about different feeding systems for different types of trees, but now I feed during the growing season every 10-14 days with a balanced feed knowing that the daily watering regime during this period will wash away any excess fertilizer before the next dose.

Conclusion

Cat litter is a cheap, easily obtainable alternative bonsai soil that will help to keep your bonsai growing vigorously with regular watering and feeding regimes.

Yamadora collecting

There isn't many jobs that can be done this time of year, especially when your collection of bonsai is as small as mine is at the moment. The indoor bonsai need normal attention, watering, light trimming etc., but the outdoor bonsai are already starting to prepare for the winter. Protecting them from the cold, especially the cold wind, will be my priority during the next month to 6 weeks. After this more protection is needed for the outdoor bonsai but I will return to this matter nearer the time to show how I prepare my trees for the cold temperatures that we get here in Finland.

What this time does give me is the possibility to search and identify potential bonsai (potensai) in the form of yamadora that can be collected in the spring. One source of bonsai material that I have noticed is simply sitting next to many roads and tracks. Here in Finland there is a trench / ditch along the side of the road for the rain water to run into and for the snow to be pushed into during the winter months.

Trees grow in these trenches which are cut each year by the verge cutters that come along to cut the grass and weeds. The continual cutting of the tops of the trees produces thick trunks that is the heart of any bonsai.

Any type of common tree in our area can be found growing in the trenches as shown in the photos. The most common tree in the photo was Aspen (Populus Tremula) but there was also a Scots pine.

I know that Aspen is not a common tree for bonsai material, but if nothing else it will allow me to continually improve on my bonsai skills. Now we wait for the spring to see how some of these trees look when removed from the ground.

Japanese maple #1

The cold nights are starting to come now in this part of the world. These nights start to turn the leaves on the trees all different colours. We have some big maple trees in our garden and the tops of these turned almost bright red. Maples are of course very good at showing off their colours and Japanese maples in particular display such wonderful colours at this time of year.

This is the same tree I purchased from Bauhaus that will need an immediate repot next spring, but you can already see that in a few years once the canopy has developed further this should be a nice tree.

Scots pine #2

This Scots pine (Pinus Sylvestris) was collected a couple of weeks after the first Scots pine.

This was located on the side of a rock and again the roots were all on the surface of the rock, making it easier to collect. Bringing along as many roots as possible, not forgetting the Mycorrhizal fungi, helps to make the survival rate of pine trees higher.

The photos below show the sort of location that these potensai can be found. Places exposed to the weather where the wind can blow strongly and the tree is attached by only a little soil are ideal conditions for nature to make the sort of tree bonsai enthusiasts are interest in.

Scots pine #1

The truck on this Scots pine (Pinus Sylvestris) is one of the reasons I broke my back to collect it. The shape and size of this tree takes years to establish and is clearly one of the reasons why the best bonsai material (potensai) can really only be found from mother nature herself.

The tree was found on top of a hill and completely exposed to the elements. There was not much soil around the tree and, fortunately for me, all the roots were growing on top of the rock that made up the hill.

Once it was collected and back home I made the wooden box, I have learned that planting the tree back into the ground is not the best solution long term, that will be it's home for the next 2 years. I started immediately feeding the tree and continued to feed every 2 weeks with a balanced soluble feed. This it seemed to like because new needles started to appear in many areas, even areas that were almost without any needles. Now I need to nurse it through the winter and then wait patiently for next spring to see if I have learned something from my many hours of studying.

Scots pine yamadora

Scots pine (Pinus Sylvestris) is one of the most common trees found in Finland. A couple of years ago I collected some Pine trees and planted them into the ground at my old house. These continued to grow in the ground without any adverse affects. When moving house last year I had to remove them from the ground and plant them into large pots. Unfortunately because of my lack of experience these died over the winter period because they had so little time to recover. I had planted them into the pots too late in the year and with little to none of the original soil.

I have since been reading many hours of information available on the internet about the collection of Pine trees and armed with this information went about collecting a couple of trees at the end of summer. This period is the best time to collect or even repot this type of tree because the roots are more active during the autumn than earlier in the year. I also collected much of the surrounding soil containing the all important Mycorrhizal fungi. This fungi helps to get the nutrients from the soil through to the roots and can take many years to grow. Retaining this fungi in the collection or repotting process is very important for the survival of Pine trees.

Japanese maple #1

This Japanese maple (Acer palmatum) I purchased recently from Bauhaus here in Raisio. It was on offer at the time and cost only 20€. This price isn't bad if you think that it is already in a pot measuring 20x14x7cm.

The only problem is that the soil the tree is planted in is quite heavy. Ideally this should be changed to allow me to water and fertilize the tree like the others I have in my collection.

Unfortunately this isn't the time of year to start repotting trees. I will take extra care of this tree during the Autumn and Winter months, especially with the watering, until I can change the soil in the spring.

Fukien tea

This fukien tea tree (Carmona microphylla) was purchased already as a bonsai from a local store. It was on sale at the time so I brought it. If nothing else it gives me an opportunity to practice bonsai techniques on this tree.

I have earlier had fukien tea trees and they have all died. I think this was mainly due my reluctance then to change the soil fearing that I would kill the tree that was growing so well at the time.

This time I knew that if I didn't change the soil then it would go the way of the other trees and die. I repotted this in the spring a few weeks after I purchased it, this gave it time to acclimatise itself to my home. It has since been growing well in my own soil mix of 1/2 fired clay and 1/2 pine bark.

Bougainvillea # 1

This bougainvillea was started from a cutting. It had been growing in a standard plastic pot for 2 years.

The bougainvillea was planted into this pot in the spring. I have yet to decide how I want this bougainvillea to look so I have allowed it to grow and only cut back the long shoots once they have reached approx. 5-6 nodes.

Weeping fig

This fig (Ficus benjamina 'natasha') was purchased from a garden centre. All three figs were included in the same pot.

I repotted these figs in the spring. The roots were quite tangled together being potted in the same pot, but I managed to separate them enough to plant in this pot. The figs now need some wiring to improve the look, this I will do in the next couple of weeks.

Norway maple # 4

This maple had already been growing for a few years at the bottom of our garden and has a very interesting shaped truck.

When I dug this up from the ground I had already decided that I wanted to place the exposed roots over a rock. I used clear cellophane to wrap the roots to the rock and separate this area from the soil so that the roots would grow downwards. I then planted the tree and rock back into the ground.

I also buried a slab in the ground and placed the tree on top of this slab to force the roots to now grow sideways once they were out the bottom of the cellophane.

The image above shows the portion of the tree that I have planned to keep. This will mean that I will remove the long branch from the final design. I have left this to grow at the moment as this was the only section that had leaves plus it helps to thicken the truck and roots while allowing the tree to grow unrestricted.

Norway maple # 1, 2, 3

Norway maple (Acer platanoides) is a very common tree in the south of Finland. There were two big maples in the garden of our old house and each year new shoots would start to pop up all over the ground underneath the big trees. A few I took and planted into the ground and left to grow there for 3 years. During the winter the rabbits would come and eat away the brackets. We moved house at the end of last year so had to dig them up if I wanted to bring them with me.

The size of the leaves are quite big and I am told that they are not easy to reduce, but I will at least work on them and let's see what happens. If nothing else it will be good practice doing the normal tasks (trimming, pruning, repotting etc.) that is required to make a normal tree into a bonsai style.

The tree below is possibly the variety "Crimson King" which has dark purple leaves. Believe it or not the tree had been the ground the same amount of time as the above two maples but has only grown 10 cm in height.

All these trees were removed from the ground in October 2008 and potted into these pots. I understand that this would not be recommended to do so late in the season, but it was either that or leave them for the new owners to maybe dig up and destroy anyway.

Yellow birch

This birch (betula alleghaniensis) was also purchased from a garden centre.

This tree is probably not one of the best trees to have as a bonsai because the size of the leaves are quite big, but it was the truck that attracted me to this tree. Good nebrei can also be seen which is always an important aspect of making a good bonsai.

It was repotted in the spring and I found that the roots where shallow enough for me to be able to place it straight into a bonsai pot.

Amur maple

This maple (Acer tataricum ginnala) was purchased from a local garden centre.

What attracted me to this maple was the thick trunk and exposed root. The original height was over 1/2 metre and the was reduced at the end of last year. The tops of the branches can still be seen through the leaves. These will be further reduced or removed completely once all the leaves have fallen and I can have a better idea how the new branches are forming.

The tree was repotted in spring in my own bonsai soil mix of fired clay and pine bark roughly 1/2 and 1/2. The maple had to be repotted into a deep pot because of the size of the roots. It was not possible to remove all the big roots until some finer roots have started to grow closer to the surface.

Welcome to Raisio Bonsai

Welcome to my blog where I will inform and show my ups and downs of making bonsai here in Finland. I will post pictures of my current bonsai / potensai (potential bonsai) and in future show the various steps to try to turn my various trees into bonsai.