This article was reviewed by the following bonsai experts gratis:
– Jerome and Mari Kellerhals from The Bonsai Supply in Fort Lauderdale, Florida
- Don’t over-water your tree if the soil still has moisture at the top half inch or so – too wet can be even worse than too dry (not only can it drown the roots, but it can also cause mold growth), so make sure your pot drains properly.
- With no contact with the massive thermal sink that is the ground, trees in pots are very sensitive to fluctuations in environmental temperature, so keep them away from extreme heat (light direct sunlight) or cold.
- If you see stringy silver lines on the soil that reappear after removing them, it could be fungi that is not necessarily harmful to the tree. On the other hand if they are the byproducts of insects or molluscs it could mean bad news so check the bottom of the pot for any infestations.
- Some people check if their Ficus is dead by peeling away some bark and checking if it is green inside, but often dead trees will keep their color for a while so it isn’t a foolproof method. Browning and dryness is also quite a reliable indicator of a tree’s upcoming death.
- Tropical trees (such as ficus) should be kept away from cold temperatures, but feel free to let it breathe some fresh outside air during warmer months (this is actually necessary for health).
- If your new bonsai has rocks glued on the top of the pot, remove them and replace them with small stones or sand.
- If you want to thicken a tree trunk, avoid pruning it for a while. To only enlarge a part of the trunk below a certain point, only prune above that point for a few months. Another way to induce trunk thickening is to cause some trauma to the bark to slightly separate it from the tree – in principle it’s similar to a broken human bone growing to fill in the gap.
- While evergreen trees like ficus can be repotted at any time of the year, they still show metabolic slowdown in winter so you may want to wait until warmer seasons.
- Bonsai needs airy soil that drains well – anything that’s dense and holds onto water won’t be good for the roots. Also any soil mixture should be mixed well rather than layered separately – you do not need a separate layer for drainage.
- When repotting, get rid of the soil that was stuck around the roots as otherwise if the new soil has a different composition, then there may be two conflicting watering requirements in the one pot.
- Worms are not suitable for bonsai, as the coarse soil ideal for them are inhospitable for worms.
- Wooden containers are not good for bonsai that will stay in it for a long time as wet wood is susceptible to decay and more inviting to pests.
- Fluorescent lights are the best bulbs to use for indoor trees as they don’t get too hot, which is important since it’s good to place them close to the tree for maximum light exposure.
- Between 25-33% of roots should be removed when repotting (but avoid repotting trees in poor condition).
- With store-bought bonsai, avoid or return ones that have loose roots.
- Humidity trays and sprays are both great for moisture – they also happen to rhyme.
- While neem oil is great for mold, using it too much unnecessarily can choke your leaves.
- Leaf loss on ficus is not necessarily cause for alarm, as any kind of shock (change in temperature, light, humidity, soil, water, wind) can trigger it and usually they will start to grow back in a few weeks. Deciduous species are especially prone to cooler temperatures that mimick fall.
- Artificial pest-control products can actually damage your tree (everything from the leaves to the roots, eg. it can brown Junipers).
- Watering too much can be the cause of yellowing leaves that soon drop off.
- English walnut trees are moderately hardy but cannot withstand very cold climates. Nuts will grow on them, but it may be a strain on such a small tree (physically and biologically).
- If your Chinese elm has dry and discolored leaves, it could be because you are using tap water that has a high chlorine content.
- When removing shoots from a Juniper to shape it, use your fingers rather than tools to minimize damage.
- Submerging the pot in water is not something that should be done often – perhaps once in a blue moon to wash away unwanted substances. However it may be the only way to water it if the tree is rootbound (the root filling the whole pot).
- Signs of a tree being rootbound include the tree being pushed out of the top of the pot, soil that stays wet and doesn’t drain (and subsequent mold growth) and no bubbling when you water it.
- Plentiful but infrequent watering is preferable to frequently watering in small amounts.
- Ficus do best with lots of light, preferably sunlight.
- A Juniper branch that is dead will be dark inside.
- If you prune Junipers too close to winter, new buds can appear that can get injured from freezing weather. These injuries can lead to greater susceptibility to diseases and pests.
- Shoots at the bottom of a tree are best removed because they direct nutrients and water that would otherwise reach the ends of the tree.