Posts Tagged: soil pH
Hydrangeas Are Better Than Ever!
A few years ago, back during the drought, I was ready to give up on hydrangeas. They were the...
Early Summer Problems -- Tomatoes, Roses, Flowering Pear Tree, Soil pH
Advice from the Help Desk of the
UC Master Gardeners Program of Contra Costa County
Client: I'm having some early summer problems in my garden. I'm reluctant to use pesticides in my garden since I have several small children. Would you please provide some recommendations to either cure and/or minimize the problems:
- Tomato plants are doing reasonably well but there are some funky looking lower leaves that I'm concerned about.
- My roses' leaves are mottled with brown-red markings.
- The flowering pear tree's leaves are mottled and dropping; an arborist recommended injecting a chemical into the tree to cure the problem
- I suspect that my garden soil is too alkaline (i.e. previously tested pH@7.1). How can I test it and what can I do to reduce pH? Will just adding compost reduce pH?
UCMGP's Help Desk Response: Thank you for the photographs, which were very helpful. Our responses follow:
Flowering Pear Tree: The photograph from the flowering pear confirms that it is infected with Entomosporium, another fungus that is spread by splashing rain. http://ipm.ucanr.edu/PMG/GARDEN/PLANTS/DISEASES/entomoslfspt.html. We do not think that this disease warrants fungicide treatment. I do not know what chemical the pest company was
Soil pH: Home test kits for soil are fairly reliable as long as the instructions are followed carefully. A pH of 7 - 7.5 is borderline satisfactory, but may go up over time because our municipal water tends to have high pH. We recommend that you wait until the plants have been harvested and then add garden sulfur to the soil in the fall according to label directions. Lowering the pH with sulfur takes time (i.e., months), so you must be patient. Adding compost will not lower the soil pH.
I hope that this information is helpful. Please do not hesitate to contact us again. Good luck on a successful summer garden.
Editor's Notes: It is likely that the tomato, rose, and flowering pear tree problems may have been caused by the late rains creating conditions conducive to fungus: cool, humid conditions. Warmer, drier weather should minimize these types of fungus infestations provided there is adequate air circulation and not overhead watering early evening.
Help Desk of the UC Master Gardener Program of Contra Costa County (JL)
Note: The UC Master Gardeners Program of Contra Costa's Help Desk is available year-round to answer your gardening questions. Except for a few holidays, we're open every week, Monday through Thursday for walk-ins from 9:00 am to Noon at 75 Santa Barbara Road, 2d Floor, Pleasant Hill, CA 94523. We can also be reached via telephone: (925) 646-6586, email: ccmg@ucanr.edu, or on the web at http://ccmg.ucanr.edu/Ask_Us/ MGCC Blogs can be found at http://ccmg.ucanr.edu/HortCoCo/ You can also subscribe to the Blog (//ucanr.edu/blogs/CCMGBlog/).
Copper Deficiency in 'Meyer' Lemon - It Can be Gross
A 'Meyer' lemon should be quite happy along the coast, unless it gets planted in new soil that has low copper because of high soil pH or high organic matter. And then you wonder what is wrong.
Mild copper deficiency is usually associated with large, dark green leaves on long soft angular shoots. Young shoots may develop into branches which appear curved or “S-shaped," referred to as “ammoniation” usually resulting from excessive nitrogen fertilization. It's actually thought to be too much nitrogen relative to copper in the plant and can be corrected by foliar sprays. Twigs can develop blister-like pockets of clear gum at nodes. As twigs mature, reddish brown eruptions may occur in the outer portion of the wood. It can be quite shocking. Severely affected twigs commonly die back from the tip with new growth appearing as multiple buds or “witches broom”. Necrotic-corky areas on the fruit surface may sometimes occur in extreme situations. In some cases fruit cracking occurs with exudates.
Copper deficiency is more likely to occur in new plantings on previously uncropped soils, which are usually deficient or totally lacking in copper. In California, it has been referred to as “corral” disease or “midden” disease because it is associated with high organic matter that ties up the copper, or old Native American sites were debris had been piled. It is often localized in certain areas. Once I saw it on nursery trees that had had inadequate copper in the nutrient solution. I've only seen it on citrus, and not any other subtropical like avocado, but that doesn't mean it can't happen.
I've also seen gummosis similar to this occurring with drought and water management. It more commonly occurs as a twig die back at the tips. And certainly Phytophthora gummosis will show gumming. It's that little gumming pocket under the bark is usually the way to distinguish copper deficiency from these two others.
Pictures: pocket gumming (U. of Florida), oozing (Yara), gumming, and more gumming not a worm
copper deficiency
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