June 2009

A good practice for better landscapes


Would you like to have healthier plants, better soil and use less water?† Regular use of mulches can give you all this and more.† What, exactly, is mulch?† Mulch is organic material that is at least partially composted and then used as a protective covering placed around plants to prevent evaporation of moisture, freezing of roots, and weed growth.† It can be coarse or fine and even consist of rocks in some landscapes. ďCompostĒ is mulch that had completed the composting (or decomposition) process. Mulch is for surface applications only, while compost can be used as a planting mix.


Regular use of mulches also helps drainage and improves the soil.† Most mulches release natural humic acids when broken down by soil microbes.† These acids neutralize alkali deposits frequently found in our native soils and make nutrients more readily available to plants.† Mulch also cools the soil while reducing water use during the hot summer months.† Some mulches like bark and rock are highly decorative in the landscape.† Others can also be used as amendments to improve soil at planting time.† Here are examples of the most common mulches normally used in our area:



Dr. QísPaydirt

Humus Gro

Top Dressing


Bulk or bagged rock

Grass clippings




Dr. QísPaydirt Premium Planting Mix and Mulch is a peat moss based, fully composted product with long-lasting organic fertilizer added.† It is free of sewer sludge and breaks down naturally, over time, when used as a surface mulch.† Best when applied as a 1 or 2 inch layer twice a year in spring and fall.† Specially formulated for our tough desert soils, Paydirt is also the best soil amendment available!† Mix it with landscape soil to get all your plants, flowers and vegetables off to the best possible start.† (top)


Humus Gro and Top Dressing are fully composted, humus-based products that give a rich color to the soil surface when used as mulch.† They also break down naturally when used as surface mulches and release beneficial humic acids.† These products can also be used as seed covers and soil amendments.† Apply 1 or 2 inch layer in spring and fall to provide maximum benefit to plants.† (top)


Bark mulches insulate the soil from heat and cold as well as control evaporation.† Coarse, medium and large bark mulches are especially useful in high-wind areas since they arenít likely to blow around like fine-grained products.† Apply a 2 inch layer around plants and in shrub beds.† Do not mix bark mulches into the soil.† They remove nitrogen during the composting process and can cause plant stress if used incorrectly.† Scatter fertilizer on top of the bark when feeding your plants.† It will speed composting while providing proper plant nutrition. ††(top)


Bulk or bagged rock is a decorative landscape product that doubles as mulch by reducing evaporation from soil in covered areas around desert shrubs, trees and cactus.† Rock is normally applied in 1 to 2 inch layers.† Since it is highly heat reflective, be careful when using it around traditional plants.† Leave a 2 or 3 foot circle around those plants and use bark or humus-based mulch instead.† If using rock over a large surface area, keep in mind that sandstone rock decomposes into soil rather quickly, while quartz rock does not.† (top)


Grass clippings and leaves are frequently used as mulches by the home gardener.† If using these materials, be sure to keep them out of the soil structure as they remove nitrogen while undergoing the natural composting process.† This can cause severe plant stress.† Consider building a composting bin (wire fencing works well).† Add the leaves and clippings, sprinkle with high nitrogen fertilizer like Ammonium Sulfate (21-0-0).† Water and turn the pile over every 2 weeks or so.† Youíll have a fully composted mulch in about 6 weeks which will be fine to use around your flowers, trees and shrubs.† (top)

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2009 Star Nursery, Inc.