Bonsai are completely reliant on us for their nutrients to help them photosynthesise, most good free draining potting mixtures are inert and do not provide nutrients for the tree mediums such as Akadama are not able to retain nutrients for long and so frequent feeding is required.

If you want your bonsai to grow well they need to be fed regularly, some people think that to get small growth you starve a tree – you will get small growth for a while, followed by

a dead tree!

Bonsai cultivation can be stressful for a tree and so it is imperative that the tree is kept in good health and a good feeding technique is key to this.

Only feed trees once they are actively growing feed less later in the season since the tree is not as active and needs less food, some people use a no nitrogen feed later in the season so that new growth is not promoted.

If feeding a well refined deciduous tree it is okay to hold off feeding until the first flush of growth is completed to help to keep growth shorter, but you must then follow up feeding after this to replenish the tree’s internal food supply. Do not feed freshly repotted trees, new roots can burn if too much feed is given, better to wait about a several weeks and gradually build up feeding. Do not feed a very weak tree or sick tree

Fertilisers contain Nitrogen (N), Potassium (P) and phosphorus (K) and also sometimes trace elements. The N-P-K number is shown on fertiliser packaging and a balanced feed is generally best (5-5-5, etc) nitrogen helps leaves to grow, potassium aids root growth and phosphorus helps fruits to grow (remember, shots, roots and fruits). Therefore tailor your fertiliser to the job on hand – if you are looking to develop a tree quickly, then higher N and P value fertilisers are better. Vigorous flowering and fruiting varieties will benefit from higher K values.

You can use solid or liquid feed, chemical or organic, just remember to think why you are feeding and used feeds with the appropriate N-P-K levels.

Solid feeds effect lasts longer as they are broken down slowly and feed the tree with every watering. Try using Naruko feed from Japan (NPK = 5-5-5), and this typically lasts four weeks before redosing. Solid feeds may form a mould on them – this is normal and shows it is working. Also, slightly burying the feed keeps it moist and is more effective in its release of nutrients.

Try not to use chicken manure since it smells an attracts flies, other solid feeds like Vitax Q4 are good alternatives if you cannot get hold of Naruko. Also you can get hold of other feeds like rapeseed cakes or Biogold, but these can be expensive.

Place solid feeds around the edges of the pot where the newer roots are, this ensures that the feed gets to the active roots and gets into the tree.

Liquid feeds are also good for giving trees a quick boost, but unlike solid feeds they do not feed much after the first treatment since they are easily washed out of the pot. Some people use a reduced liquid feed with every watering. Alternatively, feed a liquid weekly, or biweekly during the growing season.

Suitable liquid feeds are seaweed extract, fish emulsion, other organic or chemical liquid feeds. Again remember to use a balanced feed unless to specifically want to promote growth or fruit.

Try to use several different fertilisers through the season for best effect, some might have certain micronutrients others lack, and combining several in one season hopefully covers any deficits.

English Elm leaves

English Elm leaves


  • Well fed bonsai trees are healthy trees
  • Only feed when the tree is growing, and is not sick or freshly repotted
  • Choose a fertiliser that suits the type of growth you want (quick growth vs tree refinement)
  • Mix and match several fertilisers for the best effect

Article by Mark Kerry March 2015 of Newbury & District Bonsai Society