Bonsai Fertilizer

rob_thompson(5)May 15, 2009

I have a question about complete fertilizers for Bonsai's. I understand that for most Bonsai's, the recommended rate of fertilization with liquid fertilizer is every other week during the growing period and monthly during the winter months. Most sources mention something about "half strength" liquid fertilizer, but don't say anything about N-P-K. I consulted Howard Resh's book on Hydroponics which gives very detailed formulas for nutrient mixes. All of the commercial formulas he surveyed seem to have an N-P-K ratio of about 6-1-6. This isn't too far off the current Miracle-Gro all purpose fertilizer, which nicely contains trace elements as well.

However, Micracle-Gro lacks Calcium, Magnesium, and Sulfur. Adding a teaspoon of Epsom Salt takes care of the Mg and S nicely. In my garden, I get lots of Calcium from lime and Bone Meal. But I understand most Bonsai's like slightly acidic soil (pH 6.0-6.5), so lime is out. And adding Bone Meal monthly doesn't seem like fun. I water in Calcium Nitrate on my Tomato plants to prevent blossum-end rot, but does anyone know how much to use on Bonsai's for supplemental Ca?

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In my opinion you are overworking it some and mixing what you would do with garden plants with small/large trees in a pot. When in the US (Pennsylvania) I never fed any of the field material which was growing on. The bench trees were given a shot of MG in the spring for about a month then I went to Fish Emulsion for the rest of the season.

Feeding was done with a siphon feeder, they got a very low dose of feed every watering (once or twice a day depending on weather).

What I now do, under vastly different conditions, is feed as little as possible. I mix a very small amount of (old) bull manure into the mix and some burned rice straw. If I want a tree to go nuts on me for a while I simply add a high N fertalizer then step back. During the 3-4 months of the monsoon they get nothing.


    Bookmark   May 15, 2009 at 8:08PM
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