Chet Notes The Greenhouse

Bonsai Care

March 31, 2021

Bonsai trees come from a long artistic tradition of training tree forms to grow dwarfed. This art form has it’s origin in Japan and China where it has been practiced for centuries. Bonsai trees are grown in pots and are completely dependent on the grower for care, and therefore need some added attention compared to other indoor plants. With proper care, a bonsai will stay dwarfed with beautiful foliage for years to come.


Spring, Summer & Fall – When nightly lows do not dip below 40 degrees, your bonsai should be placed outside on a patio, balcony or in a garden where it will receive sufficient sun. Bonsai grow best in morning sun and afternoon shade.

Winter – Once nightly lows begin approaching the 40 degree mark, it is time to bring your indoor bonsai inside. The ideal indoor location is on a window sill that receives at least 4-6 hours of sunlight to keep the bonsai healthy.


Watering is vital to the health of your bonsai. Always water when the soil appears dry, and never allow it to become completely dry. If your bonsai is receiving full sun, it may be necessary to water once a day. However, this schedule may vary based on the size of pot, type of soil and type of bonsai you own. Evaluate each trees water requirements and adjust your watering schedule to accommodate it. An optional way of keeping track of your watering is to use a moisture meter until you get to know your bonsai tree. Always water with a watering can or hose with attachment to ensure soft flow of water that will not disturb the soil. If your plant is outside, a good rain is normally sufficient watering.


During the cold months when your bonsai is inside, we recommend placing it in a shallow tray filled with a layer of gravel and water. This provides extra moisture around the tree as the water evaporates and reduces the amount of moisture lost to modern heating systems.



Fertilizing is necessary for a bonsai to remain healthy and beautiful. Since your bonsai is growing in such a small amount of soil it is necessary to replenish the soils supply of nutrients periodically. A general-purpose liquid fertilizer, available in our greenhouse, will do fine. We suggest that fertilizers be used at half their recommended strength. Fertilizer should be applied at least once a month except during the winter months. Your bonsai will also respond well to foliar feeding, with a water-soluble fertilizer applied every other month as a spray.


Training deals with the art of bonsai and should be thoroughly understood before undertaking – or left to a professional. Most of the true bonsai trees you will find, including those available in our greenhouse, have already been through their training period and therefore require only periodic trimming and pinching to remain miniature.


To keep your tree dwarfed, pinch and trim back the new growth to the farthest safe point.You should never remove all of the new growth. A little should be left to sustain the health of the tree. tropical and sub-tropical trees used for bonsai will require periodic pinching and trimming throughout the year. Since different trees grow at different rates, you should adjust your trimming and pinching to accommodate this.



Re-potting must be performed periodically on all bonsai when their root system has filled the pot. The reasons for re-potting are to supply your tree with fresh soil and to encourage a more compact root system. As a rule, most deciduous trees require re-potting every two or three years, while evergreens only need to be re-potted every four or five years. Since trees grow at different rates, this schedule will not always hold true, therefore you should examine your trees root system each year to determine if it has become pot-bound.

In most cases, the potting process is easy and safe if performed properly and at the right time of year. Re-potting should be done mid-summer. The tree, along with all of its soil, should be removed from the pot. The outer and bottom most fourth of the trees root mass should be removed. This is done by raking the soil away, then pruning back the roots. In most cases, it is not good to prune back more than one fourth of the trees root mass. After this, the tree can be placed back in it’s original pot or into another. the pot should have screen placed over the drainage holes. Then a thin layer of small gravel is placed in the bottom of the pot for drainage purposes. On top of this gravel is placed the new fresh soil. Place a layer of well-draining soil which is sufficient enough to elevate the tree to its previous height in the pot. After placing the tree back in the pot, the area left vacant by the pruned root mass should be filled with fresh soil. This fresh soil should be worked in around and under the root mass in such a manner as to avoid leaving any air pockets. After, re-potting, your bonsai should be thoroughly watered. This can be achieved by submerging the entire pot in a tub of water. Moss or other ground covers can be used to cover the surface of the pot to help prevent soil erosion when watering.


Since your bonsai is a dwarfed tree, it can be treated for insects and diseases the same as any other tree. If you discover any insects or diseases, visit our greenhouses to find information and products to eliminate the problem.


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