Mostly, when I write about feeding plants, I refer to amending the soil to enable the micro and macro biological life of the soil to break down organic matter into forms the plant can uptake. It's a long term, low maintenance principle of gardening. Additional information about our soils, the soil amendments and amending them is covered in my section on Understanding and Amending Our Soils.
Maintenance feeding is in addition to soil amending. Maintenance of xeric beds is minimal. By summer, many plants in newly installed beds will double in size and begin to flower. Some may not flower until next year depending on plant choices. When the soil is properly prepared for a low water-use bed, no additional fertilizing is needed. Plants will thrive on slow release nutrients the compost (please read below the section on contaminated compost) provides.
Applying high nitrogen fertilizers (chemical fertilizers) is harmful by causing too rapid a growth in xerophitic plants and in harming the soil organisms (usually because of the salt-based formula fertilizers come in). The concentrated doses of nitrogen applied to xeric landscapes stimulates rapid formation of woody fibers. Xeric plants are naturally slower growing, allowing the woody fibers to harden and strengthen over time, supporting the characteristics that enable them to survive in extreme conditions. Increased, rapid growth stimulation causes weaker growth, putting plants under stress (or death) during extremes of temperature (rapid temperature shifts), wind or drought. Rapid growth also changes the appearance of the plants from the neat compact plants we expect to rangy overgrown plants that give gardeners the urge to prune back. Our perception of xeric plants and gardens should be more in tune with their actual environments, and not expect results or artificially stimulate to produce results replicating lush, humid climates that naturally promote profuse and rapid growth.
If a decline in vigor is noticed in following years, pull back the rock mulch and apply a half inch to inch layer of fine compost or soil amendment with trace minerals and high quality compost blend. Nutrient blends such as Soil Mender's Yum-Yum Mix can be added yearly as well. A simpler method to boost your plants during the stress of summer would be to water with compost tea or apply liquid organic fertilizer such as liquid humate, microbe stimulator, horticultural blackstrap molasses and/or a seaweed or fish emulsion product as a foliar spray.
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. (Growing Solutions, & Soil Soup).
To make your own aerobically activated compost tea, you will need an air infused system, such as an aquarium air pump, 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. De-chlorinate (degas) water in a couple of hours in open air. Check with your Water Department to determine if they use chloramines, which will not degas. Using rainwater is a better 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 the garden.
Pour the liquid on plants or spray 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 (Kimas Tejas Nursery, Compost Tea Article). 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. Reading the book, Teaming with Microbes, a Gardener's Guide to the Soil Food Web is an excellent resource to learn about microbial soil life and tailoring microbe food for different plant groups.
Amending the Soil in an Existing Landscape
Beds and Borders
To increase the fertility of your existing perennial beds or borders for medium and high water-use plants, 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 soil conditions until good soil tilth is attained. This is a long-term process.
Topdressing turf is a similar technique to be used in lawns and over large areas. After aeration of the turf, spread 1/ 2 to ¾ inch 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.
One cubic yard of compost will provide a
- ½ inch layer over 648 sq. ft.
- ¾ inch layer over 486 sq. ft.
- 1 inch layer over 324 sq. ft.
- 2 inch layer over 162 sq. ft.
- 3 inch layer over 108 sq. ft.
Topdressing with compost is a labor intensive activity. If you are not physically able to do this, after aeration of the turf, use a fertilizer spreader to broadcast alfalfa meal, cottonseed meal or other products according to the instructions on the bag. Typical applications are:
1 to 5 pounds per 100 sq. ft.
3 to 5 pounds per 100 sq. ft.
10 pounds per 1000 sq. ft.
blend of ½ composted manure, ½ alfalfa meal
(Humalfa by Hu-more or other similar bag blend)
100 pounds per 100 sq. ft.
corn gluten meal
15-20 pounds per 1000 sq. ft.
bag composted manure
40 lbs per 25 sq. ft for a ½ inch layer
There are 27 cubic feet in 1 cubic yard. If you are buying compost by the bag, rather than by bulk, it will take
- 90 -- 3 cu/ft bags to cover 1000 sq. ft. to a depth of 3 inches
- 45 -- 3 cu/ft bags to cover 1000 sq. ft. to a depth of 1 ½ inches
- 30 -- 3 cu/ft bags to cover 1000 sq. ft. to a depth of 1 inch
or it will take
- 120 -- 2 cu/ft bags to cover 1000 sq. ft to a depth of 3 inches
- 80 -- 2 cu/ft bags to cover 1000 sq. ft to a depth of 2 inches
- 40 -- 2 cu/ft bags to cover 1000 sq. ft. to a depth of 1 inch.
Be sure to measure the turf areas and beds and borders to insure ordering adequate quantities of organic or inorganic amendments. Once you know the size of the area, you'll be able to properly feed your plants.
Organic Foliar Applications
Liquid applications of compost tea, aerobically activated compost tea, liquid humate, fish emulsion and other organic sprays either add microbes to the landscape or stimulate microbial activity. Foliar applications can be made anytime during the growing season, March through November, to the plants -- tops and undersides of leaves. Follow the directions on the container, applying the suggested amount per square footage of landscape.
When converting from chemical fertilizers to an organic care program, foliar sprays will boost the health of the landscape. Likewise, during times of heat, wind or hail stress, foliar applications will augment the organics applied to the soil. Do not rely solely on organic foliar sprays to provide food for plants. For healthier soil and longer term benefits, solid organic matter needs to be added to the soil. The low maintenance, ecological-friendly landscape requires organic matter in all stages of decomposition in the soil to support a healthy soil food web. Foliar spraying should be considered only as a temporary, higher maintenance boost, not a regular bi-weekly practice.
Herbicide Carryover – Killer or Contaminated Compost
Unfortunately, one of the most natural and beneficial products, compost, is becoming contaminated. Farmers and home gardeners across the United States have reported damage to vegetable, flower and fruit crops after applying composted manure (whether from cows or horses) or composted hay, straw or grass clippings to the soil. Shortly after these applications as soil amendments or mulch, they noticed stunted growth, poor germination, death of plants, deformed plants and fruit. In most cases, the damage was caused by a group of synthetic chemicals known as pyridine carboxylic acids, sometimes referred to as pyralids, namely, aminopyralid, clopyralid, fluroxypyr, picloram, triclopyr and/or aminicyclopyrachlor. Products containing these chemicals include Curtail, Forefront, Grazon Next, Grazon P+D, Milestone, Redeem R&P, Surmount, Confront, Lontrel, Millennium Ultra Plus and Plus2, Clopyr AG, Stinger and Imprelis. In September, 2009, Mother Earth News reported that a previously considered organic product, Grab 'n Grow, contained one of the above chemicals and caused damage to a vegetable garden of Grab 'n Grows manager, Don Liepold. Subsequently “I have been testing and detecting herbicide residues and thus rejecting cow manure, horse manure, turkey mulch, rice hulls, mushroom compost and yard trimmings,” says Grab n’ Grow manager Don Liepold. “I spent $20,000 in lab fees in 2008, and am on the same track for 2009,” he says.”
The Mother Earth News article continues “It is extremely difficult to keep contaminated materials out of commercial compost. “One load of contaminated grass clippings can ruin a batch of compost,” says Eric Philip of Anatek Labs in Moscow, Idaho. Philip has seen so many positive tests for clopyralid residues in compost that he would not use untested compost in his own garden.
“When folks have plants die in their home gardens, their first assumption is that they did something wrong,” Philip says. But with pyralid-laced commercial compost becoming more common, contaminated soil amendments are often to blame.
The effects of contaminated compost and composted manure might be transferred to foliar sprays as well, although I have not read any reports mentioning them specifically.
The source of pyralid pollution can be impossible to trace. For example, a horse stable may use hay brought in from a neighboring state, without knowing that it is laced with pyralid herbicides. If the horse’s manure or stable litter ends up in a garden, disaster is ready to strike. It’s better to be safe than sorry. Liepold stopped making one of Grab n’ Grow’s most popular products, Mango Mulch, for more than a year because he could not find an uncontaminated manure supply. Now he’s getting it from two local organic dairies.”
Mother Earth News first sounded the alarm on “killer compost” in 2008, and has continued to report as new information comes to light. In 2011, Dupont's Imprelis, an herbicide praised for being a “green alternative” because of its long residual, made headlines as it killed trees and shrubs in numerous states from New England across the Midwest into the northern Plains States. Currently, the EPA Stop Sale Order on Imprelis, but not on the other products by Dow AgroScience and Dupont.
Dupont did notice that Imprelis could create killer compost. From Page 7 of the 9 page label on Dupont's Imprelis: “Do not use grass clippings from treated areas for mulching or compost, or allow for collection to composting facilities. Grass clippings must either be left on the treated area or, if allowed by local yard waste regulations, disposed of in the trash. Applicators must give verbal or written notice to property owner/property managers/residents to not use grass clippings from treated turf for mulch or compost.”
It is well known that the “label is the law”. How many people do you imagine read the entire label when purchasing herbicides? Although Imprelis was sold only to licensed applicators, how many of them read the label or warned home or corporate owner/managers when they applied Imprelis of the long term effects regarding compost? In areas where community composting is practiced, it is easy to see how contamination of these resources can occur.
North Carolina University Cooperative Extension issued an excellent bulletin entitled “Herbicide Carryover in Hay, Manure, Compost and Grass clippings warning “farmers and home gardeners of reported damage to vegetable and flower crops after applying horse or livestock manure, compost, hay or grass clippings to the soil,” (http://www.ces.ncsu.edu/fletcher/programs/ncorganic/special-pubs/herbicide_carryover.pdf). Although the above mentioned products were licensed for use in agriculture by licensed applicators, Imprelis was licensed for use on residential lawns by licensed applicators.
Just because many of these products were for agricultural use, doesn't mean home gardeners are safe from the herbicides long term effects. The warning for vegetable growers and home gardeners is to be aware of your source for hay, straw, manure or compost from hay, straw or manure. These herbicides can be active up to four years or more. The person you purchase or receive these products from may not even know this class of herbicides have been sprayed on them, or be aware of the longterm effects.
Here is an example of why it is difficult to find out. A friend of yours offers you horse manure that has been composted. You might ask him/her if herbicides were used, with the farmer replying the manure/compost is "safe" because the animal has not been effected. The horse or cattle were fed hay that was sprayed with one of these herbicides (it's reported not to be harmful to animals). The horse eats the hay, and the resulting horse manure contains active residues of the herbicide, even after it composts. You spread the manure in your vegetable garden and your vegetables are stunted and fail to thrive, or die outright.
You might think this couldn't happen to you, but a case very similar to what I described happened to a family member of mine. After he did some research, he went back to the neighbor where he got the manure and found out the man did indeed spray his hay with one of these chemicals.
Unless you are absolutely sure hay or straw does not have a history with these herbicides, I would not use them in compost or on your garden soil or ornamental beds.
The affected composted manure would be safe to spread on your turfgrass. To be safe, I would not compost the grass clippings or use the grass clippings in beds or borders. It would be safe to cut your turf with a mulching mow, returning the clippings to the soil if you had already used contaminated compost there. I'm unsure of the effects of these chemicals on trees (except for Imprelis). The North Carolina bulletin goes on to describe how to do tests to determine whether the compost or hay/straw contains residues of one of these herbicides.
The latest warning has come from Mother Earth News, published in the February/March 2013 issue. They noted that livestock feeds now contain the contaminated chemicals and are passed through the animal into the manure in this manner. Because of the growing contamination problem, Mother Earth News advises gardeners that “the time has come for the public to stop buying compost or manure products unless they come from suppliers that are able to afford testing and can screen feedstocks for herbicide residues.”
Once again, the buyer needs to be very aware.
Read More: a FAQ sheet from the US Composting Council on contaminated compost: http://compostingcouncil.org/persistent-herbicide-faq/