Check for proper drainage
WASHINGTON - This rainy spring will be remembered as the season that gardens didn't need irrigation. Grass was lush; shrubs and trees stayed wet; ponds and outdoor planters didn't require topping off.
Joel M. Lerner is president of Environmental Design in Capitol View Park, Md., and author of Anyone Can Landscape (Ball 2001). For more information, go to www.gardenlerner.com.
Other than weeding, it was a labor-free spring - provided your property was well drained.
When the ground doesn't drain properly, it gets muddy. Nothing grows but bog plants, mold and algae. Even if you have a tiny plot of land or a single tree, the area must drain. Two types of water control are necessary to the health of your property: surface drainage and soil percolation.
Surface drainage
Water in the basement is the most serious problem caused by poor surface drainage. In almost every situation, the problem is the lack of surface water runoff or runoff in the wrong direction - toward your basement instead of into an area that drains well.Causes can include low spots hidden by planting beds or shrubs too close to foundations, or downspouts and gutters that don't carry storm water away from the house. Correcting the problem can be simple. Before considering solutions such as sump pumps, wall excavations, waterproof paints, or sophisticated underground drainage systems, inspect for low spots near the foundation.
To fix the problem, channel storm-water runoff. Generally, I suggest a downhill slope dropping three to six inches per 10-foot run. If a grade slopes down and away from your home, and continues slightly downhill, your basement will stay dry and the area should remain well-drained and usable for plantings or picnics. Basement walls or foundations for concrete slabs should have a grade that drains away from structures.
Do-it-yourselfers commonly overlook surface drainage when installing landscape features. Patios, walks, and mounded beds can cut off existing grades, creating puddles that render these areas useless whenever there is precipitation.
Another common error is installing walks or patios perfectly level. This creates a situation that will hold water and promote the growth of fungi and algae. Paved surfaces should be laid so they drop one inch over 10 feet. This is less than a 1 percent grade, and it will seem level to the eye and foot.
Even if water in the basement is not a problem, check the drainage patterns around your house during a storm to make sure all water rolls away from the downspouts and walls. An ounce of prevention can save you gallons of problems and a barrel of mosquitoes.
If you see that water is not flowing away from your home, add soil to create a downhill slope along the walls. The fill should have a high percentage of clay in it and be low in rock, sand or compost.
Soil percolation
Storm water doesn't always flow away from your property; it can be retained a little longer on site. This could be by choice, or because it's a boggy site with poor soil percolation, meaning water doesn't drain quickly enough.To determine before planting if you have a problem with standing water, dig a hole, fill it with water, and see how long it takes to drain. The length of time depends upon the size of the hole, but you'll know if you have poor drainage. I have dug holes, filled them, and had water standing 24 hours later.
Most plants will not do well in hard, poorly drained soil. Improve the drainage by digging up to one-third compost into the native soil that is not allowing percolation. Dig it in as deeply as 12 inches and improve the soil over as wide an area as possible.
Use a rotary tiller to break up the dirt if the area is too large or the soil too hard to dig with a shovel.
Joel M. Lerner is president of Environmental Design in Capitol View Park, Md., and author of Anyone Can Landscape (Ball 2001). For more information, go to www.gardenlerner.com.
