Saturday, November 26, 2016

Rain Draining Strategies

When rainstorms come pouring through California each winter, think about this: Where is all that water going when it lands in your backyard? Here are some tips to protect your house, pool cover and prized outdoor plants located in low lying areas:

• Enjoy the rain...from indoors. Do as little as possible in the garden during a downpour. Working in wet soil causes compaction. 


• Add gutter extensions to move water away from the house. These sections of flexible pipe allow you to divert water several feet away from plants that don't like wet feet. And, it may keep your house foundation drier, too.

A better system for draining water away from house gutters or garden beds that habitually have slow water percolation: a hard pipe drain system. Surface drains lead to three-inch PVC pipe, buried beneath the soil and sloping down towards the lowest part of the property or to an outlet.
 Be sure to slope the drain pipe, allowing at least a one foot drop for each 100 feet of length (one quarter-inch per foot). Dig backwards from where the water will exit the pipe, trenching back towards the source of flooding to help determine how deep to lay the drain pipe. Line the trench with a few inches of gravel, both above and below the pipe. For a lawn area, try to lay the pipe at least two feet below the surface.


• Get a submersible sump pump to move water in a hurry from pool covers and planted areas that flood. Some models are water activated (they automatically come on when the water level rises an inch or so). Place the sump pump on a board to keep dirt from clogging the filtration screen.

• Dig a hole. A hole (also called a sump) that is dug in the lowest portion of your yard, a hole that penetrates through all the layers of hardpan (usually 2-4 feet below the surface), can help drain away storm water. Line the hole with a non-porous material (hard plastic sheeting, for example) to keep the surrounding dirt from falling back into the hole. Fill the hole with small rocks, about one inch in diameter.

• Construct an underground hard drain or a French drain (perforated drain pipe or gravel creek bed). If it's the lawn area that's flooding, dig a trench and lay a drain line in the lowest area of the lawn. Don't do any digging immediately after a heavy rain, though; wait until the soil dries enough to avoid unnecessary soil compaction. Be sure to slope the perforated drain pipe, allowing at least a one foot drop for each 100 feet of length (one quarter-inch per foot). Dig backwards from where the water will exit the pipe, trenching back towards the source of flooding to help determine how deep to lay the drain pipe. Line the trench with a few inches of gravel, both above and below the pipe. For a lawn area, try to lay the pipe at least two feet below the surface.

• If it's the garden bed that's flooding, consider building raised beds this fall, lining the bed with 2X8, 2X10 or 2X12 redwood planks. Capping off the top of these boards with 2X6 redwood will give you a comfortable place to sit while harvesting vegetables and pulling weeds.


• If you haven't planted in a flooded area yet, consider creating mounds first, planting trees and shrubs on the top of the mounds.

 If you're still stuck with pools of standing water after heavy rains despite your best efforts, consider planting trees and shrubs that can take "wet feet". Water-tolerant trees for many areas of Northern and Central California include sweet gum, magnolia, and tupelo. Shrubs for wet areas include thuja and red twig dogwood.

Thursday, October 27, 2016

The Year of the Splitting Orange

Washington Navel and other varieties of citrus are beginning to ripen in our area, and many backyard gardeners are horrified at what they are seeing currently, wondering if Mother Nature is pulling some sort of Halloween prank.
 Jim asks: “I have a beautiful navel orange tree and for the past two years the fruit keeps splitting. The oranges start out fine and all of a sudden as they get bigger, they split right down the middle.”
Donna chimes in: “My reliable orange tree is going south. I watered it for 10 minutes every morning and evening during summer. Is this splitting issue a disease?”
Teresa, writes to the garden e-mail bag: "My mom has a wonderful orange tree, and the fruit is just starting to grow. However, most of them are splitting before they even get larger than a fist. What makes them do that?"  Steve echoes this chorus: “Why are my oranges splitting now?”

You may be facing the same conundrum with your own backyard citrus.

    The short answer: splitting oranges are usually due to stress to the tree, usually a combination of fluctuating temperatures, humidity, soil moisture and possibly fertilizer levels. Oh, and an on-going drought.

    The long answer, from Pam Geisel, a UC Cooperative Extension Farm Advisor, who has studied the problem of citrus split: When hot weather is combined with high winds, navel orange trees become drought stressed and begin to take water from the young fruit, causing the fruit to soften and the leaves to cup. If the tree is then irrigated heavily, the dehydrated fruit swell, causing them to crack. Young trees or dwarf varieties with relatively small or shallow root systems, as well as trees grown in very sandy or porous soils that do not retain moisture well may be more susceptible to fruit splitting.
    Backyard gardeners can help minimize fruit split in navel oranges by paying attention to the summertime weather forecasts. When hot winds are predicted, irrigate before the winds begin. After the hot winds subside, irrigate lightly for a few days and then resume a normal irrigation schedule. Adding four inches of an organic mulch to the surface beneath the tree can also moderate soil moisture loss, as well as feeding the soil and controlling weeds.

Geisel also advises: "Instead of a single large application of quick release fertilizer each year, smaller monthly applications throughout the growing season (Feb. through May) may help keep nutrient levels constant."
Citrus grower Lance Walheim, author of the book, "Citrus", says that a good watering pattern for oranges includes adjusting it to the weather. Allow the top three or four inches to dry before irrigating deeply. He explains that too much water retards the spread of roots and promotes soil-borne diseases. An orange tree that gets too little water will grow poorly and may die. Keep an eye out for the signs of moisture stress on the orange trees: wilting or off-colored foliage.

    Ask a dozen citrus growers how they fertilize, and you may get 12 different answers. The University of California has several recommendations: "Apply one application of nitrogen (ammonium nitrate, ammonium sulfate, or urea) in late December to February. Alternatively, fertilizers can be applied in several applications. Many commercial growers apply 1/3 of the total nitrogen needed in February, July, and September. Using a balanced citrus food may help to correct mineral deficiencies as well as provide a more complete nutrition. Manure should be applied in the fall so that the winter rains can leach the salts. Steer and chicken manure should be used sparingly because they are high in salt and may burn the trees. Mature citrus trees use 1-1.5 lb. of actual nitrogen (N) per tree per year."
I'm no fan of quick release, ammonia-based products; it's too easy to apply too much, and could damage your tree. Others have weighed in on why these salt-containing formulations are bad for your garden. But for those of you that can't resist those $3 bags of Sulfate of Ammonia piled up outside the drug store, remember that Sulfate of Ammonia (20-0-0) consists of 20% actual nitrogen. So, applying one pound of actual nitrogen over three feedings per year per mature citrus tree equals about a pound and a half of ammonium sulfate per application, spread evenly beneath the outer dripline of the tree, following the label directions.
     My citrus feeding regimen for my containerized (half-barrels) citrus trees is organic, applied every other week during the growing season (February through September): a combination of water soluble fish emulsion and sea kelp. Fertilizer leaches through containerized plants more quickly than in-ground plants. So, a light feeding, but more often (every other week instead of monthly), mitigates that loss.

There are plenty of complete and balanced organic fertilizers available for fruit trees, some that only need to be applied a few times a year.
Timed-release synthetic fertilizers offer the convenience of supplying  nutrients at an even rate, but are usually more expensive. 
Whichever fertilizer you choose, apply it according to the label directions. 
     Lance Walheim also advises against fertilizing oranges after the end of summer. Late applications of fertilizer to deficient trees, he says, can lower fruit quality, make  the rind tougher and exposes new growth to the ill effects of a winter freeze.
    There are no pests or diseases that cause splitting, nor is there a chemical control for it, explains Pam Geisel. It is a problem that stems from environmental or cultural conditions. Blame the weather this year. Next year, mulch, water and fertilize that navel orange tree correctly to help minimize the fruit split.