Alright I admit it!, when I first became aware of bonsai in the mid 1970's I, like a lot of beginners thought that the mystique of bonsai was in keeping them just this side of dead. One of the things that never occurred to me was to feed them, believing that they would get all the nutrients they needed when repotted into fresh soil. Needless to say that not many of those trees are still around.
I should point out that you are not feeding the tree to make it grow, you are replacing the nutrients the tree has used because it's growing and that feeding a sick tree is a recipe for disaster. Only feed healthy trees!
When developing a young bonsai, the last thing you want to do is to starve it, adding years to the time it takes to get the tree 'Showable'. As the tree matures you may wish to slow it down a little, you can achieve this by varying the type of feed given, away from high nitrogen feeds, but not the amount.
During the growing season (In the UK it's mid March - early September) your trees should be fed once a fortnight with an appropriate feed for what you are trying to do with the tree. This would be a high Nitrogen feed for developing trees and a more balanced type for mature trees. Bear in mind that trees stop growing and hence absorbing nutrients during the high summer. As the trees begin to slow down towards Autumn feed them once a month. After leaf fall stop feeding the deciduous trees, conifers however will benefit from a couple of feeds over winter.
Indoor bonsai continue to grow throughout the year and should be fed all year.
Now we come to one of the more contentious issues in the Gardening world, Organic, or Man-made feeds. I could fill screen after screen on this matter and all it would do is to confuse (Me). The only advice I have for you is that organic feeds are less likely to burn the roots if overfed, but ultimately either is better than none.
My own preference is for pelleted Chicken manure on those trees not for show and liquid fishmeal in trees which may be shown. You will NOT want to use these on indoor trees so perhaps a feed made from seaweed or a chemical feed. |