Amending Existing Landscapes


Amending the Soil in an Existing Landscape

To amend existing beds, topdressing with organic and inorganic matter is recommended. To increase the fertility of your existing perennial beds or borders, pull back any mulch covering you already have. Add a three-inch layer of good quality compost and gently work it into the top few inches of bare areas between the plants. Earthworms will do the rest. As the years go by, your earthworm population should increase.

If you don't want to disturb the mulch, poke holes with a garden fork or hand aerator in the beds and pour a fine compost blend down the holes. Repeat this process spring and fall, or more often depending on your soil conditions until good soil tilth is attained. This is a long-term process.

A similar technique may also be used in lawns and over large areas. After aeration, spread the compost on the area with a rake. Repeat this process each spring and fall. This is an effective technique for supplementing nutrients for trees as well.

Foliar feeding is an even higher maintenance activity. Higher maintenance because is needs to be repeated often. Liquid compost, worm tea, liquid seaweed. trace minerals, liquid molasses, liquid humate and other organic liquid products can all be used. Follow directions on the container. But to improve the soil texture and soil organic content, organic solids need to be incorporated into the soil. Their are thousands of different types of microbes that perform many different functions for the plants and soil requiring organic matter (carbon) in different forms.

Compost Tea

You may decide to improve the soil by spraying with compost tea to add nutrients, stimulate microbial growth or inoculate microbes to the bed and/or landscape. Improvements have been made to the way compost tea is brewed.

Compost tea that has been properly aerated contains increased biotic life, and is called Aerobically Activated Compost Teas, or AACT. To make Aerobically Activated Compost Tea, start with good aerobic composted manure, vermicompost or compost you make yourself that has a good earthy smell. You can purchase a tea brewing system, or make your own. To purchase a brewing system, go the Internet and type in compost tea in the address bar. Several AACT companies should come up.

You will need an air infused system, such as an aquarium air pump and air stones and a paint strainer bag. Add 1 – 2 pounds of compost to a paint strainer bag for a five-gallon container of water, 1 – 2 ounces of horticultural molasses and fill with chlorinated-free water. Don't over feed the microbes; it's better to underfeed than overfeed them. You can de-chlorinate (degas) your water in a couple of hours in the open air. Check with your Water Department to determine if they use chloramines, which will not degas. Catching rainwater and using it is a good option. Hook up your aerator. Float the bag with compost above the air stones.

Let it steep for 12 – 24 hours, in the shade to keep the mixture cooler in the summer. If it smells bad, it went anaerobic. Throw it out. It should smell like good rich, earthy compost. Pour off the solids from the bag into your compost pile or use as mulch in other areas of your garden. Pour the liquid on plants or spray your xtreme beds or borders and landscape in general with the compost tea. Use within 24 – 36 hours, the microbes begins to decline after that. A five-gallon container will inoculate and foliar feed an acre; it takes only 44 fluid ounces, ½ gallon, for each 1000 sq. feet. Excellent for container plants as well.

Repeated applications of AACT provide needed microbial and organic content to compacted, starved or abused soil. It's an effective way to rejuvenate tired and worn-out soil and hard-to-amend turf areas.

 

Angie Hanna

 

 

Points of Interest

Basic Gardening Principles (Xeriscape Principles)

  1. Plan and design
  2. Analyze and amend the soil
  3. Create practical turf areas
  4. Efficient use of water
  5. Choose appropriate plants
  6. Use mulches
  7. Practice appropriate maintenance

Ecologically Friendly

  • Plant best adapted species
  • Plant in preferred season
  • Balance mineral content of soil
  • Build and maintain soil organic content—humus
  • Do not harm beneficial soil life
  • Consider insects and diseases as symptoms of a violation of one of the above guidelines.

Our Soil Conditions

  • Sandy or compacted clay or caliche
  • Alkaline soil pH, 7 – 8.5 pH
  • Deficient in organic matter
  • Saline or sodic soils
  • Hardpan conditions may be present

To insure the success of any bed, your primary job as a gardener is to build the soil.

Before digging to amend the soil or create new beds, consult with utility companies for the location of underground utility lines to avoid severing them.

 

Layering method of creating beds from cool season turfgrass in clay & caliche soil

  • Lay down 4-6 sheets of newspaper
  • Add inorganic amendment
  • Add compost
  • Add topsoil, if needed
  • Leave open to precipitation
  • Wait 2-4 months
  • Turn everything under with garden fork down to 8-12 inches
  • Break up clods
  • Moisten and wait 2-4 weeks
  • Turn over again or rotor till
  • Add more compost if necessary
  • Work it in
  • Plant in the proper season.

Layering method for sandy soil

  • Add new style inorganic amendment if needed, topsoil and compost for water retention
  • Otherwise, same as above

Creating beds from bermudagrass turf

  • Spray bermudagrass with glyphosate based herbicide
  • Two or more applications 2 weeks apart during the growing season
  • Wait two weeks
  • Turn soil with garden fork
  • Work in soil amendments as necessary to 8-12 inches
  • Moisten and let bed rest 2-4 weeks
  • Plant in the proper season

Double Digging

  • Measure off the bed
  • Remove turf sod and set aside for composting
  • Dig trench 1 foot wide, 1 foot deep
  • Pile soil on ground cloth or wheelbarrow
  • Go back and loosen soil at bottom of trench with fork or pick axe
  • Add compost and other amendments if necessary and mix
  • Measure off 2nd trench bed and remove sod for composting later
  • Dig 2nd trench adjacent to first
  • Toss soil from 2nd trench into first trench
  • Break up clods before tossing as you go
  • Loosen soil at bottom of trench with fork or pick axe
  • Add soil amendments in 2nd trench and mix
  • Continue until bed is dug
  • Loosen soil of last trench and add amendments
  • Add soil from the first trench into the last trench
  • Moisten trenches
  • Bed should be 3-6 inches higher depending on quantity added.
  • Allow bed to settle before planting.

Benefits of Organic Matter in the Soil

  • Improves water retention
  • Less water required when ample minerals and nutrients are present
  • Improves soil structure
  • Feeds & increases biological soil life
  • Earlier soil warming
  • Improves nutrient retention
  • Balances the pH of the soil
  • Buffers chemicals and reduces toxicity
  • Recycles waste products

Average Amendment Requirements

  • High water-use plants—6-12 inches of compost
  • Medium water-use plants—4-8 inches of compost
  • Low water-use plants—3 inches of compost

Organic Amendments for Initial Soil Amending

  • Composted cottonseed hulls
  • Composted leaf litter
  • Composted garden and grass clippings
  • Certified organic composted manure

A Few Other Organic Amendments (follow bag application guidelines)

  • Cottonseed meal
  • Alfalfa pellets and meal
  • Cocoa bean hulls
  • Corn meal and corn gluten meal
  • Horticultural molasses
  • Worm castings, bat guano
  • Fish emulsion, fish meal, kelp meal
  • Bone and blood meal

Inorganic Amendments for Increased Drainage, Water & Nutrient Retention

  • Turface® (calcined clay) for clay soil and Profile™ for sandy soil
  • Tru-Grow® (expanded blue shale)
  • Ecolite™ (zeolite)
  • Axis® (diatomaceous earth)

Other Inorganic Amendments

  • Crushed granite
  • Granite sand
  • Lava sand
  • Greensand
  • Glass sand
  • Regular sand (without the addition of lime)

Overcoming Extreme Conditions Thru Soil Amending

  • Reduces compaction and helps in-soak of precipitation
  • Reduces alkalinity of soil
  • Increases the organic content of soil
  • Helps balances the mineral content of the soil
  • Buffers saline and toxic soil conditions
  • Lessens the amount of irrigation
  • Provides more water and nutrients for timely plant recovery when faced with windy conditions, hail damage and damage caused by rapid temperature shifts
  • Expanded palette of low water-use plants that are marginally cold hardy for our area with increased drainage.

Water Conservation Through Soil Amending

  • Increases in-soak of precipitation and irrigation—minimizes runoff
  • Holds water in the root zone longer—minimizes leaching
  • Increases the drainage ability of the soil
  • Less water is required for nutrient uptake with sufficient soil organic content

Suggested Reading

  • Dirt Doctor’s Guide to Organic Gardening, Howard Garrett, University of Texas Press, 1995.
  • Gardening Success with Difficult Soils, Limestone, Alkaline Clay, and Caliche, Scott Ogden, Taylor Publishing company, 1992.
  • Soil Biology Primer, published by the Soil and Water Conservation Society in cooperation with the USDA Resources Conservation Service, 2000.
  • Soul of the Soil, Grace Gershuny, Chelsea Green Publishing Company, 4th Edition, 1999.
  • Start With The Soil, Grace Gershuny, Rodale Press, 1993.
  • The Garden-Ville Method, Lessons in Nature, Malcolm Beck, Published by Garden-Ville, Inc., 1998, recently revised.
  • The Soil and Health, Sir Albert Howard, Devin-Adair Company, 1947, reprinted by Schocken Books, New York, 1972.