We are all busy people. Sometimes we cannot keep up with all our bonsai pruning when juggling jobs, parenthood, spouse/sig-others, and other responsibilities. If you find yourself in such a position, remember one thing: keep fertilizing your trees! Once the rat race of your life has calmed down, you’ll be able to sit down for some relaxing bonsai time and your trees will be healthy. There is nothing worse than having the time for your trees and realizing that they are in such bad condition that you could harm them or there isn’t enough foliage or branches to wire. If you keep them healthy, they will be waiting for you.

It is one of the most common questions we receive from club members and the general public. What do you feed with? When do you feed? My answer is always, with everything and as much as I can! Too simple? Lets break it down…..

1. What do you feed your trees? The answer is not quite as simple as “everything”. You will find many answers to this question. Bonsai-purists insist on only organic fertilizers. Cottonseed meal, bone meal, blood meal, fish emulsion, sea weed mixes, etc. All of these products are great for your trees. They take a little longer to breakdown so the nitrogen, potassium, and phosphate are not available to your trees immediately. But, the greatest argument for their use is the trace elements they provide. Not to mention they usually don’t require tons of fossil fuels to produce. There are some great sources for these products. Any local garden store will have a nice selection of organic fertilizer. Some will have mixes of nutrient-providing materials. In general, pick one that has a balance of nitrogen, phosphate, and potassium such as 2-2-2 or 5-5-5.

Applying an organic fertilizer can be tricky. You can mix our own and make fertilizer cakes that are easily placed on the surface or just apply the power directly to the pot. Some people even make a fertilizer-tea. All of these will work but be careful. The fertilizer will break down and can clog your soil preventing good drainage of water out of the pot. The best remedy I’ve seen for the application of organic fertilizers is using tea bags. Go to your favorite tea shop and buy a package of empty tea bags, fill them with your favorite fertilizer, and just lay them on the surface of your soil. When you water, all the nutrients will be soluble in the water, and the inert material will remain in the tea bag. No problems. Another problem with organic fertilizer - especially those made from animal products (blood meal, fish meal, etc) is its ability to attract scavenging critters. Yes, everything from skunks, raccoons, your neighbor’s golden retriever, and even ravens will be highly interested in the yummy (it’s all relative) smell coming from your bonsai pot and they cannot resist the urge to investigate. In case you are wondering, that means digging out all the soil around your precious roots. So, make sure your trees are secure from the local wildlife.

As for chemical fertilizers, there are many brands and formulations. The major advantage to using a chemical fertilizer is the instant availability of the nutrients. Pick any major brand and you’ll be safe. A few cautions: 1) Chemical fertilizers can be concentrated and can harm your plants. It is possible to over fertilize which can cause leggy growth or destroy the microscopic root hairs that feed you trees. 2)They are the horticultural equivalent of fast-food for your plants. All simple nutrients designed for putting on vegetation quickly. Think giant corn-producing mega-farm product! Our trees are grown for the long haul so we need a bit more nutrition. A snack of chemical fertilizer may be okay, but try not to rely on it. There are water soluble organic fertilizers that work great as well.

2. When do you fertilize? Once again, not a straight forward answer. For those of you in the Bay Area, consult the BSSF Bonsai Care calendar. It will guide you for the correct time to fertilize depending on the plant species. When it is time to fertilize, there are a couple approaches. For the grower with limited time, consider any of the time release fertilizers. You can stuff some all-purpose organic fertilizer into a tea bag or try a chemical slow release fertilizer (ie., Osmocote). Every time you water, a bit of fertilizer will be released to the soil. These will work, but be aware that some chemical time-release fertilizers do not release nutrients evenly over time. If you use them, remove the spent granules and replace them monthly.

Timing wise, you should aim to fertilize twice per month. Mark the first and the fifteenth of the month on your bonsai calendar. Choosing every other week can be confusing and the time can be shifted month-to-month.

Personally, I choose another time schedule. If your bonsai soil is fresh and extremely free draining (you water every day or twice per day), consider fertilizing weekly. I use a water soluble fertilizer at half the recommended strength. Every Saturday morning, I water my trees with this mixture. When you have free draining soil, you reduce the chance of salt buildup from the fertilizer will harm your trees. Plus, since the trees are watered with freshwater during the week, the excess fertilizer is rinsed away. Regular addition of fertilizer assures you that the trees will always have the nutrients they need to grow as much as possible during the growing season. Especially when trees are in the developmental stage.

-Lawrence LeClaire

Tags: Beginner, Fertilizer