When the weather gets hot, properly placed trees can improve your comfort and lower your air conditioning costs by blocking solar energy before it enters your home. It's worth some special effort now to take care of your trees so they can save energy for years to come.
Spring is the best time to fertilize your trees. Trees in need of fertilizer often have small leaves or slightly discolored leaves. The best fertilizing method is to create holes in the ground that are 10 to 20 inches deep and an inch wide using a rod or auger. Place them in concentric rings around the perimeter of the tree, starting three feet away from the trunk and extending out to one-and-a-half times the diameter of the crown. Then pour liquid or granular fertilizer into the holes.
It is best to fertilize when the soil is relatively dry because spring rains or deep watering can help distribute the fertilizer. Tree fertilizers are usually described according to how much nitrogen, phosphorus, and potassium they contain, and common formulas (with these elements listed in the same order) include 16-20-0 or 10-30-10. For small trees, use about two cups of fertilizer per tree. For large trees, use two cups. In sandy soils, apply half as much fertilizer twice as often to reduce loss of fertilizer.
Water your trees deeply and only during dry weather. Avoid frequent shallow watering. Water for approximately one hour per inch of trunk thickness. Water with an open hose or soaker hose at the drip line of the tree (if you drew a line from the longest of the tree's branches to the ground, this is the drip line). Mulching the tree's base helps to maintain moisture while still allowing air circulation.
If the sunny side of your home has no trees, spring is a good time to plant new ones, too. Plant tall trees close to the home to block the overhead sun coming from the southern part of the sky. Plant shorter trees on the east and west to block low-angle morning and afternoon sun. Remember, too, that trees will shade your lawns and other plants, reducing outdoor watering costs and effort.
Source: John Krigger, Saturn Resource Management (www.srmi.biz). John Krigger is a nationally recognized author of numerous energy efficiency books, including Surviving the Seasons, and Residential Energy: Cost Savings and Comfort for Existing Buildings. For more info, visit his website www.srmi.biz.