The Right Way to Water Your Lawn and Garden

Improper watering is the number one cause of plant failure. Knowing how wet the soil is at the root level can help you keep your plants healthy. 

Keep in mind: different plants have different watering needs. Learn those needs, then group plants together with similar watering requirements. The Sunset Western Garden Book is a good source for that information.

Signs of not enough water at the root level of plants: 
Wilted leaves in the morning.
Red-brown margins of leaves.
Premature fall color of leaves.
Growth reduction.
Leaf drop.
Branch dieback.

Signs of too much water (also called aeration deficit) at the root level of plants:
The soil has a foul smell, like rotten eggs.
Soil is a blue-gray color.
Yellowing, wilting and/or dropping of leaves.
Limited new growth.
Small, corky outgrowths on the undersides of leaves.


Be warned, though: sometimes, symptoms of overwatering and underwatering can be the same (such as leaf wilting). And, symptoms of soil water problems may actually be another problem...that was caused by the watering problem! Root rots, for example, thrive in saturated soils.


Frequent, light watering leads to shallow rooting, increasing the chances of plant problems.

To determine the amount of water at the root level:

• A day or two after watering, dig down 8 to 10  inches with a trowel or small shovel, near the drip line (outer canopy) of the plant. Doing this in two or three spots would be more helpful.

• At that depth, grab a handful of the soil. Squeeze that handful. If it is muddy and watery, reduce your watering for plants that require regular (but not frequent) irrigation. If it is so dry you cannot form a clod in your hand (it turns to dust instead), increase your watering (for those plants that require moderate amounts of water).

• If you can form a dirt clod in your hand, yet break it apart with a little effort, that is probably the correct soil moisture for your plant.

• Steve Zien, owner of the Citrus Heights-based organic landscaping consulting service, Living Resources, recommends the use of a soil sampling tube to determine the moisture at root level. "Just press the tube down six to eight inches into the soil after you are done watering," says Zien. "When you bring it back up, the open slot along the side of the tube will let you see if the soil at that depth is wet, moist or dry. Adjust your watering time so that the soil sample is moist, not too wet or dry."

• An easier, but more unreliable way to measure the water content of the soil: purchase an inexpensive (under $10) moisture meter. Test its accuracy by putting its probe into a glass of water. If the probe does not read "wet", choose another. Expect it to function for only a year or so.

• Battery operated moisture meter probes may set you back a few more dollars, but in my experience - with proper care (clean them after each use, don't leave them outdoors) - they will last many years.

 

• Extended, infrequent, slowly applied irrigation is the most efficient watering method. Soaker hoses or drip irrigation systems work best. Here in the Central Valley, foothills, and Bay Area, run them for 3 to 6 hours at a time, twice a week, in the summer. This is only a guideline to get you started. Adjust that timing to your particular soil type and plants.

• And, don't forget: add more drip emitters and drip lines as the plant grows, especially for trees and shrubs. Make sure to get water to the outer canopy of the plant (and beyond) where the roots travel.

How much water does your lawn need? 

Some tips from the UC Integrated Pest Management Website:


• Avoid planting turf species that require frequent watering, such as bluegrass or ryegrass.
• Design your landscape to minimize water runoff onto hard surfaces and into storm drains.
• To reduce runoff, install non-irrigated buffer areas, which include water-efficient plants or permeable features, next to sidewalks or on slopes.
• Aerate heavy or compacted soils, so water can easily move down to reach grass roots.
• Install an irrigation system that you can adjust to properly water areas of your landscape that have different requirements.
• Water only when your lawn needs it.
• Water requirements vary according to turf species, location, and month of the year.
• Most lawns need water when the top 2 inches of soil have dried out.
• Shady and sunny areas and different soil types will have different water requirements.
• Deeper, less frequent watering is best for most lawns. Water only 2 to 3 times a week.
• Make sure your sprinkler system isn’t producing runoff, especially on slopes. If you see runoff, use shorter watering times and repeat the cycle to allow time for the water to move into the soil.
• Water early in the morning when evaporation and wind are minimal.
• Adjust your watering schedule seasonally, and shut off your irrigation system during rainy weather.


And, the video: How Much Water Do Your Plants Need?

Cherry Maggots Come to Town

"Cherry Maggots Come To Town" would be a great name for an indie band. Unfortunately, this is one insect you don't want performing in your yard. The spotted wing drosophila (SWD), is responsible for the little worms that backyard gardeners are starting to find in their cherries, and to a lesser extent in raspberries, strawberries and blueberries. First spotted in Santa Cruz County in 2008, this pest is now throughout the West Coast, and has been spotted recently in traps in Sacramento County. 

According to Sacramento County Farm Advisor Chuck Ingels, the adult SWD is small (2-3 mm), resembling a gnat that might be found on that old piece of fruit on your kitchen counter. This one, though, has a sharp ovipositor (sort of a needle-like, egg-laying device) that penetrates ripening fruit...such as your backyard cherries, that are just a few weeks away from harvest right now.

 Adult male spotted wing drosophila, Drosophila suzukii, (2-3 mm long) has a dark spot on each wing tip.
Photo by Martin Hauser.

Adult female spotted wing drosophila, Drosophila suzukii (2-3 mm long).
Photo by Martin Hauser.

This pest might easily be confused with a vinegar fly or the western cherry fly. Western cherry fruit fly adults are much larger (5 mm) than the spotted wing drosophila adults and have a dark banding pattern on their wings. The western cherry fruit fly, which is a quarantine pest, occurs in Washington and other states but has not established in California. 

Here is a detailed description of the SWD, according to an excellent report produced by the  UC Integrated Pest Management Website on Spotted Wing Drosophila: "Adults are small (2-3 mm) flies with red eyes and a pale brown thorax and abdomen with black stripes on the abdomen. The most distinguishable trait of the adult is that the males have a black spot towards the tip of each wing. 

Larvae are tiny (up to 3.5 mm), white cylindrical maggots that are found feeding in fruit. One to many larvae may be found feeding within a single fruit. After maturing, the larvae partially or completely exit the fruit to pupate."

Among you are those who are starting to ask the question, "What garden insecticide can I buy to stop this pest...."

Let me stop you right there. The cure may be worse than the problem. Limited research has been done on this new invader to California, and the chemical that so far has been found to best control the adult spotted wing drosophila is deadly to one the best "garden good guys" around, the honeybee.

The UC IPM Website says: "Although malathion...has been shown to control the adult SWD, coverage would need to be so thorough throughout the entire tree. Malathion is very toxic to bees and natural enemies of other pests in the garden, so care must be taken to keep the application on the tree and avoid drift and runoff. Improper application can also result in injury to the tree. Application should be made about 2 weeks before harvest. Sprays must kill adults before they lay eggs. Malathion will not control larvae in fruit. 

An alternative to malathion with fewer negative environmental effects would be spinosad (Monterey Garden Insect Spray); however, it is not believed to be as effective against the fruit fly adults as malathion. Two sprays may be required at about 14 days and 7 days before harvest to get satisfactory control. As with malathion, all foliage and fruit on the tree must be covered with the spray. Partial coverage will not be effective. A compressed air sprayer will give more reliable coverage than a hose end sprayer."

Two better, safer options: dispose of infested fruit and set up traps, reports the UC IPM site: 

"Spotted wing drosophila attacks ripening fruit, and unfortunately is often not noticed in backyard trees until fruit is being harvested. Sprays at this time will not protect the crop, because maggots are already in the fruit. If only some fruit are infested, you can salvage some of the crop by harvesting the crop immediately and sorting, removing fruit with stings on the surface. Place infested fruit in a sturdy, sealed plastic bag and dispose of it in the trash. Also remove any fruit that has fallen on the ground and any infested fruit remaining on trees—this may reduce populations of flies that might infest next year's crops or later ripening varieties. In addition to placing infested fruit in the trash, it can also be buried. Composting may not be a reliable way to destroy eggs and larvae in fruit."

The report from UC goes on to say, "There is some evidence from research done in Japan in the 1930’s that traps can be used to manage SWD in backyard trees. Some trials on this method will be undertaken this summer. To try this method for yourself, make traps out of one quart plastic yogurt containers (with a lid). Drill 16 holes that are 3/16-inch in diameter around the top of the container. Bait each trap with a solution of 1/4 cup grape wine plus 1/4 cup water plus 3/4 teaspoon of molasses. In early May, about 1 month before harvest, hang 3 to 5 traps in a shady spot on the lower branches of the tree. Keep the traps up until harvest is completed. Refresh the bait if needed. These traps can also be used to detect SWD in your garden earlier in the season. Bait the trap with about an inch or 2 of white wine. Check the trap weekly for small flies with dark spots at the tip of their wings floating in the fluid. These are male SWD and will confirm that you have the pest."

The bottom line: good sanitation - cleaning up and disposing of fallen fruit and vegetables - goes a long way to thwarting many backyard pests.