Every Bonsai enthusiast knows the problem that there are times when he can't be at home and therefore can't water his Bonsai trees himself. During the summer heat even long work days can be critical when the trees need to be watered frequently.
Now and then we want to travel for a weekend or longer and then we must make arrangements to insure proper care for our Bonsai trees. Family members or neighbors are in most cases unable to cope with the trees' needs and often there is a bitter loss in the end.
For a short absence and a small Bonsai collection there are tricks and simple means which can help in case of need. For example, Bonsai trees can be placed in a plastic vat which is filled with a few centimeters of water and placed in the shade. Or each Bonsai tree is placed on bricks in a bowl filled with water which must not reach the pot. Cloth strips are then placed on the soil surface so that they reach into the water and soak it up to the soil. Another possibility is a simple lawn sprinkler which is activated by a timer clock and waters the Bonsai trees placed in its reach.
A real watering system however can be the best permanent solution and is especially convenient for longer absences. It is important that the system must be thoroughly tested before it is left to work for a longer time during the absence of the owner, in order to make sure that every tree is provided with enough water. It is also a good idea to have somebody to come and check the system and see if all the components are still in place. If for example trees are tilted by the wind the water tubes and drip heads of the trees beside it can be dislocated and will also fail to water properly. Trees that are prone to be overturned by the wind should be tied to the shelves to avoid this.
Automated watering systems, Blumat and Gardena Microdrip
A simple watering system that works without electricity and can be used either with a water tank or tap is the Blumat system. Its porous clay cones, either long ones for deep pots or short ones for shallow Bonsai containers, are pushed into the soil and provide water which comes through thin water tubes. This system keeps humous soil constantly very moist and might not perfectly moisten coarse-grained soil everywhere in the pot. When the water tank and the clay cones are drained the cones must be taken out of the pots, watered and deaerated before they will work again.
A more complex system which can water a larger Bonsai collection flexibly and accurately is the Microdrip System by Gardena. There is a huge number of different components for this system which makes it difficult in the beginning to find out what you really need.
When the Bonsai trees are taken to their winter quarters in autumn, the supply pipes with the drip heads are removed and along with the water computer, master unit and rain sensor they are stored in a dry and frost-free place until next spring. Reinstallation each year in spring is unfortunately quite laborious for a larger Bonsai collection.
This watering system, including all drip heads for about 100 trees, cost about $800. Below, there is an installation example explained and illustrated.
The massive cornel cherry needs quite a lot of drip heads. You can use T-joints to build branches of the supply pipe.
This is how the pipes meander along the shelves. About three to six trees, depending on their size and the number of drip heads, are attached to one supply pipe which emerges via T-joint from the thicker connecting pipe.
Depending on the shape of the tree and pot the drip heads can be arranged in different ways. For this tree inline drip heads were combined in a ring pattern.
The little shohin Bonsai are also watered properly by the system.
The shohin trees are fastened to the shelf and the drip heads are also secured with wire if necessary to make sure they can't get out of place.
The connecting pipe is fastened to the backside of the shelves and the supply pipes branch off via T-joints.
Automated watering for Bonsai using a water computer, Hunter
A different approach shows the following watering system with the water computer made by Hunter and all components provided by the German "Beregnungsparadies" company.
The requirements were that the owner wouldn't have to adjust hundreds of drip heads and that uninstalling the components in autumn and reinstalling them in spring shouldn't take much time. The aesthetic impression also played a role.
Water can come from the tap, water supply well or rainwater tank. The water is led from the house waterworks to the valve box. It contains four valves (more are possible). The valves are opened by the computer for a certain time defined by the owner and then closed again. The water flows through pipes to the sprinklers. Weights are attached to the sprinklers (so that they don't wobble or trundle) which either hang or are mounted on steel posts. They have a range of up to 3.5 m and water in a circle pattern. The circles must overlap in order to make sure an area is perfectly watered. In places that can't be reached drip heads which are known from other systems have to be used.
A sensor can help to include weather parameters. The four different pipes of the system can be operated differently. If a larger number of sprinklers are used and watering is activated several times a day it can easily be hundreds of liters that are poured out each day which might also drench the garden paths and house walls.
As this system uses connection pipes with an oval profile it is recommended to lay them in the ground in larger empty tubes to make sure the pipes won't be compressed or folded. Before the winter the sprinklers are taken off and a compressor blows the remaining water out of the pipes in 5 minutes. Then the system is frost-proof. The computer is left in place and stays turned on because the warmth of its construction components keeps off humidity and prevents damages by condensation water. If you don't mind additional costs and want even more independence and safety you can combine similar systems with a video control and a smartphone app so that watering can be controlled and influenced from afar.
The complete setup of this watering system, including all the pipes and sprinklers cost about $1200.
These are the empty tubes in which the pipes are placed without folding and compressing.
On the wall the computer and the valve box are installed. The water pipe goes to the valve box from which the four pipes emerge. Each one has its own color.
This is line 1.
The course of the different pipes is well distinguishable.
On the roof the sensor is mounted which measures sunlight, air moisture and amount of rainfall and signals these data to the computer which then determines the watering time.
This sprinkler has a range of 2 meters.
This one sprays a circle of 3,5 m in diameter!
This is the view when it „rains“. Water must get under the crowns of the trees because otherwise most water will flow off the leaves and not reach the soil.
Sprinklers spraying the Bonsai trees.
Sprinklers can be installed like this if you don't want them to hang.
Read the Bonsai watering article. Article written by Heike van Gunst.