Master Gardeners On Organic Mulches, Ugly Tomatoes

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Mulches, the soil coverings many people associate primarily with weed suppression and garden decoration, also play an important part in plant health and soil structure.  The right organic mulch — as opposed to black plastic or decorative rock— can enrich your garden by:

• conserving soil moisture
• moderating temperature extremes underground
• reducing soil erosion
• adding nutrients to the soil through decomposition of organic matter
• improving soil structure
• minimizing weeds

While the benefits of mulching for soil and plant health are clear, choosing the right mulch for your garden can be confusing because it’s a game of tradeoffs.  For example, wood chip mulches, which resist compaction and blowing away in the wind, have a high carbon to nitrogen ratio that might temporarily reduce nitrogen in the soil for plant uptake, if incorporated into the soil.  Cocoa hulls are lovely, but they are expensive and can be toxic to dogs.  Straw, great for a summer mulch in vegetable gardens, is highly flammable — not a desirable thing in the Sierra foothills in August.

That said, here are some tips to help guide your decisions for mulching:

Season – Winter mulches are best for insulating woody plants (trees, bushes, perennials).  Shredded leaves, pine needles, or straw will help keep the soil evenly cool throughout the winter.  Summer mulches, best applied in mid-spring when active root growth has started, help retain soil moisture, reduce weeds and keep soil cooler during the hottest months.

Depth – Two to four inches is the suggested depth of garden mulches.

Location – Keep mulch at least six to twelve inches away from tree and shrub trunks, and one inch away from flower/vegetable stems, to avoid rot, cankers and other diseases.

Types – Here are some of the most common mulches used:

Wood chips are readily available and are considered attractive by many gardeners.  In the process of decomposing when incorporated into the soil, wood chips can temporarily rob soil of nitrogen. If wood chips are left on the soil surface, there should be no problem with nitrogen depletion.

Bark, whether shredded or in chunks, has some of the same advantages of wood chips:  it resists compaction, is easy to find, and it’s attractive (especially for a more natural look). Commercial bark can, however, be toxic to young plants if it is too fresh or has been stored improperly.

Straw or hay is often used in summer vegetable gardens and strawberry patches.  It is relatively inexpensive and can also be an effective winter insulating mulch.  Some disadvantages of straw are that it, too, can be high in carbon content, and it might contain grain seeds that can germinate.  A thick enough layer of it can also harbor rodents.

Sawdust, which can have an acidifying effect on soil, can be beneficial to acid-loving plants such as blueberries and rhododendrons.  Partly because sawdust is so fine in texture, it compacts very quickly in just one season; so, it is necessary either to fluff it up or replace it each year.

Hulls, obtained from the processing of crops such as buckwheat, cocoa and cottonseed, can add a nice visual texture to a garden bed.  However, they are more expensive than traditional mulches, and can more easily be washed away by rains or blown off by strong winds.

Yard “waste,“ such as leaves, pine needles and other non-diseased plant parts, is often the ideal winter or summer mulch, especially if you can chip or shred it into a finer consistency.  Pine needles, the bumper crop of free mulch in our area, provide excellent protection year-round, but they should be raked up and replaced annually.

Written by Rachel Oppedahl, a University of California Cooperative Extension Master Gardener of Tuolumne County.

Ugly Tomatoes

From time-tested heirlooms to the exciting new hybrids, we grow tomatoes for every fancy, including the sweet and prolific cherries, the plump beefsteaks, the vibrant early girls, and determinate tomatoes, perfect for canning.

Changing climate conditions are providing new challenges for tomatoes prone to splitting, as well as blossom-end rot, viruses, blight, and fungi.  These diseases create multiple problems but are not the only cause we have for ‘ugly’ tomatoes.  Nutrient deficiencies often produce disease-like systems.  The good news is that you can fix deficiencies.  Here is what you need to look for and what you need to know:

• Nitrogen deficiency causes stunted growth and a general yellowing of the older leaves.  Apply blood meal, well-composted manure, or soybean meal.  Be sure to read the labels for proper application.
• Phosphorus deficiency produces a purplish cast on the leaves.  Young seedling tomato plants often show this but outgrow it as the soil warms and their roots grow to reach this soil-bound nutrient.  Apply bone meal.  Protect your lungs and respiratory passages by wearing a dust mask or respirator whenever you handle fine powders such as colloidal rock phosphate.  Be sure to read the labels for proper application.
• Potassium deficiency causes the older leaf margins to turn yellow and brown.  Dead areas get crunchy and may fall off.  Apply greensand, kelp meal, or wood ashes (being mindful that wood ashes will raise your soil pH).  Be sure to read the labels for proper application.
• Blossom-end rot (BER) leaves a sunken, brownish-black spot on the bottom or blossom end of the tomato.  It is caused by calcium ‘displacement’, which means calcium is being sent to the newer, growing tissue, rather than actually being a calcium shortage.  As the plant goes from its high-growth stage to a more mature reproductive stage, BER usually disappears.  Consistent watering helps to prevent blossom end rot as well.  Also avoid using high-nitrogen fertilizers that encourage too much leaf growth.

When glancing through a small book called THE WEEDER’S READER, I found an article called ‘The Obsessed Gardener.’  I only wish I had room to share all of it with you, but let’s have fun with a few lines at least.  Are you an obsessed gardener?

You know the virtues of hand weeding………after dark.

You know the pH of your soil……All of your friends know the pH of your soil.

You have a charge account at the local garden center…..Your spouse buys all of your Christmas presents there.

You have dirt under your fingernails…..What fingernails?

You invest in fine gardening tools……You keep spare tools in your car for gardening emergencies.

You value all living things, great and small……You cheered when Bambi’s mother died.

There is more, but I think you get the message.

Don’t forget to enjoy the process of tomato growing. For more information on tomato growing check out this UC Publication:  https://anrcatalog.ucanr.edu/pdf/8159.pdf

Written by Betty Hensley, University of California Cooperative Extension Master Gardener of Tuolumne County and prolific vegetable gardener who writes gardening columns for several local publications.

UCCE Master Gardeners of Tuolumne and Calaveras Counties can answer home gardening questions. Call 209-533-5912 or fill out our easy-to-use problem questionnaire here. Check out our website here. You can also find us on Facebook.