Client's Situation and Question: My rhubarb tends to die back in the summer much earlier than I think it should or expect. I know that the soils where it is planted are marginal and I haven't fertilized the rhubarb. I do give it regular water. What is causing the early summer die back? and how can I improve the health, vigor, and survival of my rhubarb?
UC MGCC Program's Help Desk Response: We believe that the rhubarb's early die back may be due to a combination of lack of fertility and Contra Costa County's hot summer temperatures. Rhubarb plants do best if fertilized regularly. If you want to grow organically, you can use a six-inch layer of good compost around the base of the plant. The compost will provide a continuous nutrient source that may last for several months. Rhubarb also responds well to manure, but be sure that it has been well composted since applying fresh manure will burn the plant. You can purchase composted manure at a nursery or home supply store. It can be mixed into the compost before you put it around the plant.
Another contributing cause of the summer die back could be hot summer temperatures. Die back is a common response to temperatures that are too high. Although rhubarb likes plenty of sun, providing some shade on hot summer afternoons may help.
Hope this info helps your rhubarb thrive. It's a great perennial vegetable to have in your garden—does well in desserts but can also be used in savory dishes.
UC Master Gardener Program of Contra Costa's Help Desk (TKL)
Editor: Although this response is written for Contra Costa County gardeners, thanks go to the UC Master Gardeners of Sonoma County for input.
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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: email@example.com, 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 at http://ucanr.edu/blogs/CCMGBlog/.
Help for the Gardener from the
Contra Costa Master Gardeners' Help Desk
Description of Client's Question:
A client wrote in saying that he had read some advice about using coffee grounds as a fertilizer. The advice apparently also noted that coffee grounds would be a deterrent to gophers and moles. About two years ago, the client applied about 500 pounds of coffee grounds in a small area, but stopped when his lawn and some native plants started to die. (But the client did note that the coffee grounds got rid of the gophers!).
The client said that even after he ceased using coffee grounds, the plants have not recovered and the lawn still looks dead. He thought that perhaps the soil had become too acidic and perhaps gypsum could be added to remedy the problem.
Here's the advice that Master Gardeners gave the client:
Soil acidity isn't the reason why nothing is able to grow in the areas where you applied coffee grounds, nitrogen depletion is. In fact, coffee grounds don't cause soils to become acidic. The acidity in coffee is water soluble and the acidity in the beans ends up in the coffee when the ground beans are brewed.
Oregon State University recently conducted a study on garden use of coffee grounds (http://extension.oregonstate.edu/lane/sites/default/files/documents/cffee07.pdf ). OSU found that large amounts of coffee grounds stimulate the development of soil microorganisms which in turn use the nitrogen in your soil to process the coffee grounds. The study also states that acidity of the resulting soil is not the major issue, but nitrogen depletion of the soil is a major concern.
I would try using a good organic nitrogen fertilizer and applying it to the area where growth has ceased. The organic fertilizers are slow release and will not burn your lawn or surrounding plants. It may take repeated applications over time to adjust the soil composition. If you have bare ground that is affected, you could also try covering the area with compost or leaves and let the natural composting process help to balance your soil.
Editor's Note: Each month the CCMG Help Desk's Quality Assurance Team selects responses to county residents' Help Desk questions that produced informative responses that are either unique or unusual, or provided updated information that would be informative to all gardeners, or are of general interest, especially of seasonal concerns. We are highlighting these responses in the HortCOCO blog so all interested Master Gardeners and the public may utilize the information.
The CCMG Help Desk is available year-round to answer your gardening questions. Except for a few holidays, we're open every week, Monday through Thursday 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: firstname.lastname@example.org, and we are on the web at http://ccmg.ucanr.edu/