WATERING IN SUMMER. (July, 2010)
As summer heats up, the growth of bonsai slows down and sometimes comes to a complete stop. The most important work now is keeping trees well-watered.
Watch out for excessive heat and water accordingly. Protect bonsai in small or shallow pots by ensuring that a layer of clean sphagnum moss covers the entire surface of the soil to help the tree retain moisture. In particularly warm areas, place trees under 30-50% shade cloth or otherwise protect them from the hot, midday sun. Deciduous trees and white pines are especially sensitive to heat. Remove fertilizer cakes for trees in summer “dormancy.”
Check the amount of water each tree takes in. If your are not sure how dry the soil is, dig down about 1 inch and check. Since color of akadama becomes lighter as it dries out, and darkens when it gets wet, it is a great aid in helping determine water needs.
Flowering and fruiting trees such as pyracantha, apple, wisteria, winter berry and rose, need a lot of water. Insufficient water will cause these trees to drop their fruit and can affect the production of next year’s fruit.
Shohin and medium sized trees (chuhin) can be placed on a tray with porous gravel to help increase the moisture. But the trees should not sit in water. For root-over-rock trees, place a towel over the soil and the stone. Wet towels help to cool down the stone and protect the roots.
Place water loving bonsai, like wisteria, bald cypress, etc., in a shallow pan or saucer to keep the roots soaked. Do not submerse more than the bottom quarter of the pot.
Remember to rotate your trees at least once a month.