General Bonsai Care

It is important to have a basic understanding of the conditions that your bonsai species requires. It can be helpful to understand what region the tree is native to, and what sort of climate it thrives in. This will help us to replicate its ideal environment wherever we have our Bonsai. Things like ambient temperature, humidity, rainfall, daylight hours and seasonal conditions can affect how well your bonsai will thrive.

Here are some helpful general care tips to get you started!

Positioning and Lighting

If you are keeping your bonsai indoors, one of the most important things is ensuring that your Bonsai tree is getting enough light. In general, being placed in a south facing window will ensure that it is getting enough light for as long as possible during the day.

If your indoor space is lacking enough natural daylight then a grow light will be useful to ensure that your bonsai is getting enough light.

Some Bonsai are unable to cope with the higher temperatures and lower humidity inside your home. These trees are best kept outside all year round. In general, they need to be kept in an open bright part of your garden, patio or balcony. During summer, they may need to be placed in a spot with some afternoon shade if it’s particularly hot. This will help to avoid leaf burn. In Winter, wrapping the plant pot with fleece or with bubble wrap will protect the roots from freezing. Some species may benefit from being brought into an unheated greenhouse (or unheated conservatory) to protect it from the coldest temperatures. If temperatures are dropping below freezing, then avoid overwatering beforehand.

Humidity

Most indoor environments are too dry for Bonsai. A more humid environment can therefore be replicated by increasing the humidity levels immediately surrounding the plant. This can be done by using a humidity tray filled with water and by misting the plants leaves and bark with water. Remember that humidity trays and misting the plant is not a replacement for watering! So make sure that you are checking the soil saturation and watering when required too.

Outdoor Bonsai have a much higher humidity than indoors in the UK. So, in general less attention is required in regulating the humidity levels.

Watering

The key to watering is balance. Overwatering can cause root rot. If the roots are sitting in constant water then oxygen and nutrients can’t be absorbed through the roots and they begin to die. The rot can then spread to other healthier roots. Letting the soil dry slightly between watering allows the roots hairs to absorb oxygen and keep healthy. Some species are more sensitive to overwatering or underwatering so be sure to check the ideal soil conditions for your plant.

Keeping an eye on the soil or media can help you with your watering regime. Usually, it is best to wait until the topsoil feels slightly firm to touch before watering. The smaller the pot versus the size of the tree, the more often you’ll have to water it. In the heat of summer (particularly if outside) the plant will require watering more often than the dormant winter period.

Like with all plants, it is best to use rainwater for your Bonsai. If the species prefers slightly acidic soil, then be especially careful not to use tap water if you are in a hard water area. Hard water is more alkaline and could therefore alter the soil acidity.

Feed / Fertiliser

Fertilisers or feed should be used during the growing seasons. This is usually from mid spring to the middle of Autumn. Indoor Bonsai are usually sub tropical, so don’t have a dormant season and can be fertilised as normal all year round. Outdoor temperate climate bonsai should be given less or no fertiliser during the Winter months.

Bonsai specific fertilisers are usually made from a balanced ratio of Phosphorus, Potassium and Nitrogen as well as some other minerals. These help with foliage and branch development and help aid the general health of the plant and roots.

Shaping and Pruning

This is the chance to explore your creative side and show off your artistic skills! Pruning the leaves and branches back is essential in creating your intended shape and style of Bonsai and also helps to keep your Bonsai small and healthy. The idea is to create a smaller version of how the tree would look in its full size. As a general rule, branches can be cut back to the point where two leaves are still remaining. This encourages bifurcation (the branch splitting into two branches) and encourages more densely packed foliage with smaller leaves. The best time to hard prune your bonsai is usually in the spring (with the exception of Azaleas).

Wiring can help to create more movement in the trunk or limbs of the tree. Carefully wire the branch by twisting the wire around the limbs. Make sure you are supporting the branch with your fingers so it doesn’t break. Use appropriately sized wire to give enough strength to hold the branch in the intended position. Be careful not to damage any offshoots or bark by wrapping the wire too tight. Then carefully manipulate the branch with the wire on, into the position that suits you. Wiring has to be carried out with lots of patience and care to avoid any branches breaking.

In some cases, soaked raffia can be used prior to wiring to protect more delicate bark from scarring. The soaked raffia can also help to make brittle or older branches more pliable. Wiring can be applied at any time of year, but make sure that you take the wiring off as soon as the branch has been set into place to avoid bite marks. This happens when the branch continues to grow around the wire and can cause unsightly scarring.

Re-Potting / Cutting Back Roots

How often you need to repot your Bonsai will depend on; how vigorously your bonsai variety grows, the age of the plant and the conditions and climate you are growing your plant in. For example; a tree that is being looked after in a way that replicates its native environment will put out more upward and root growth and will therefore need repotting more often. Younger trees often grow more vigorously than older Bonsai so will also need repotting more frequently. Bonsai trees require repotting to maintain healthy roots and to avoid the tree from becoming pot-bound. The roots should be combed out with a root rake on the top of the soil moving outwards, away from the trunk of the Bonsai, this should also be done from the underside starting in the middle and raking outwards. While cutting the roots back, it is a general rule to not cut more than a quarter of the fine haired root mass. It is important to check for any individual Bonsai species advice before getting started.

Good drainage is important for most bonsai to prevent the roots and soil from becoming waterlogged. It is therefore important to repot your bonsai into a balanced mix of media that encourages drainage of excess water and allows a small amount of water and nutrient retention to help keep the roots healthy. If you want to encourage more growth, then repotting into a larger pot, after root trimming, may be a good idea. If you are content with the size of your Bonsai and would like to simply maintain the tree, then make sure that you clean the pot thoroughly before placing the Bonsai with the new media into the same pot.