Advice - Watering

Water abundantly and regularly with soft, room-temperature water. Watering can be a tricky matter, since Acers like neither too little nor too much water. The soil should be allowed to dry slightly between waterings.
Notice: For plants grown in pots and planters, the bright colours of the spring leaves will fade somewhat if you put your Acer in the shade for two or three days.
Pay close attention to watering in wintertime, especially if the winter is dry and your trees are not exposed to rain. (Never water if the ground is frozen.)
Growing your maples in the sun will result in dazzling autumn colours, but only up to a point: the trees can be burned (watch out for hot, dry winds). Depending on your region, you may want to mist the foliage and use netting for shade and a wind-break.
Varieties with pale or variegated leaves are more sensitive to sunlight.

A tip for Acers grown in bonsai pots:
To avoid overdrying or sun damage to the roots in summer, put a layer of sphagnum moss around the base of the tree. This encourages the growth of surface roots, helping establish a good nebari. You can then sow natural moss on the surface.