The soil you will need for a bonsai tree depends on the variety of tree you are trying to grow. Check its soil requirements before placing it in any soil. Some trees prefer acidic soil while others need neutral pHs. Flowering species will need richer soil to produce their blossoms than evergreens will need.
Most potting soils are adequate and have elements of mulch or vermiculite mixed in for good draining. If you take soil from your garden, loosen it with sand or mulch and enrich it with compost before potting a bonsai in it. As with many container plants, the soil should be loose and fertile. Fertilize regularly; bonsai shaping is easiest done with consistent growth.
Use a liquid fertilizer solution like Miracle-Gro mixed with water every two to four weeks during the growing season. Do this after watering for best results, and don’t fertilize soon after repotting a bonsai.
Any container you choose for bonsai needs to be well-drained. If it doesn’t have drainage holes, create some with a drill, pick or awl, and if this is not possible, you’ll have to find a different container. Improper drainage will kill a bonsai tree quickly. Even though the plants are small, their roots are the same as larger trees, and will suffer from being immersed in water regularly.
Consider the size you want your bonsai to grow to when choosing a container, and choose a pot that is just slightly larger than its current growth, to give you room to train the tree. If you are growing it fairly large, you will likely need to repot the bonsai after a few years in any case. Repotting should be done in the early spring, and you should choose a new container that suits the root growth and tree growth at that time.
Different varieties of trees used for bonsai require different amounts of watering, but all bonsai need to be watered more frequently in their small containers than they would growing outdoors, since their roots are confined to a small area. Keep soil for a bonsai tree moist, but not wet, and not bone dry.
As a general rule of thumb, water every few days, and pay attention to the tree’s water requirements. It’s best to water in the cooler mornings, when the moisture has time to diffuse through the soil and roots more evenly. Taper off watering and fertilizing in the late fall to allow the tree to enter its winter dormancy.
Pruning and training a bonsai tree is what keeps its miniature shape. The most pruning should be done in the spring, as the tree is putting on its new growth. Snip off new growth watchfully where it is unwanted, but be careful not to cut off all its new growth, or you will soon kill the tree. Often, bonsai gardeners use wire to direct the growth of branches.
These should only take about six months to reshape a branch, and then should be cut carefully off the branch. Cut off low growth, to help the young tree resemble a mature tree with a thick trunk. You also will want to be trimming roots in the spring or when repotting. When the root ball is exposed, reshape it to better fit its container and help the tree throw up more new foliage and stem growth instead.
Want to learn more about bonsai?
Check out these Web sites chosen by us for more information on the subject:
The American Bonsai Society can direct you to local bonsai nurseries and clubs.
Explore bonsai forms and varieties in a publication from the Virginia Cooperative Extension.
The Iowa Bonsai Association provides a guide to bonsai care.