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Manure (local)*: sheep, cattle, horse, and chicken manure
widely available from nearby farms. Ask for manure that has
been mixed with bedding material and allowed to compost and
age for at least 4-6 months. Farm manures usually contain 1%
or less each of N, P, and K. Rabbit, sheep and chicken manure
are higher in these nutrients. Manure mixed with urine-soaked
bedding will be higher in N. Approximately 20-40% of the
nitrogen is available to plants the rst year after application.
Weed problems may occur when the entire compost pile does
not reach sufciently high temperatures. A heavy organic
mulch will help smother weeds.
Mushroom compost*: used or “spent” compost from
mushroom farming. It is some combination of manures, wheat
straw, corn cobs, feathermeal, peanut meal, peat moss, lime,
etc. Mushrooms grown in this media use only a small portion
of the many nutrients. Nutrient analysis: 2.75-1.5-1.5. Can
have high soluble salt levels and should be fully incorporated
and watered prior to planting.
Peat moss*: partially composted moss mined from prehistoric
non-renewable bogs. Light and porous, it absorbs 10-20 times
its weight in water. Its high surface tension causes it to repel
water when it’s dry, so do not use as mulch or top-dressing.
Contains little nutrient value, but has a high nutrient-holding
capacity. Acidic (as low as 3.0 pH); good for working into
azalea and blueberry beds.
Pine bark nes*: a nely shredded pine bark product that
retains moisture. Sometimes a composted component of
potting media. May be incorporated into annual and perennial
beds. Very acidic, so watch soil pH levels if large quantities
are used. A peat moss alternative.
Sand*: to improve water drainage and aeration of clay soils
a minimum of 50% by volume is necessary. Use only coarse
builder’s sand, not play sand. Often impractical to use because
of the large volume needed.
Sawdust*: only well-decayed sawdust should be incorporated
into the soil. Fresh sawdust can burn plant roots and “tie up”
nitrogen as it decomposes. (Soil microbes that break down
the high-carbon sawdust need nitrogen.) Good for mulching
blueberry beds.
Topsoil*: no state or federal standards. Quality will vary.
Inspect topsoil and ask for references. Inquire where it came
from and whether any testing for pH, soluble salts, heavy
Worm castings*: the rich digested “soil” produced by
redworm farming. No guaranteed listed analysis due to
the great variability in feedstock, storage, and handling.
Concentrated source of Ca, Mg, N, P and K, in readily
available form. Used for container plants, indoors and out.
Use 1 to 2 cubic feet per 100 square feet of garden area.
Castings can be purchased through catalogs or produced at
home in redworm bins.
SOIL CONDITIONERS
Most garden and landscape plants perform best in soils high
in organic matter (greater than 2% organic matter, by weight,
in the topsoil). These soils are loose, easy to work, and have a
large number of earthworms. Organic matter is continuously
used up through oxidation, downward movement through the
soil prole, and plant growth. It should be replenished each
year in cultivated ower and vegetable beds.
Compost (commercial or "home-grown"): made from
decayed organic materials such as straw, corn cobs, food
wastes, cocoa bean hulls, poultry litter, grass clippings, leaves,
manure. Composts improve soil structure and slowly release
nutrients to plant roots. (See HG 35 Backyard Composting)
Gypsum*: calcium sulfate, a mined product also called “land
plaster.” About 20-23% calcium and 15-18% sulfur, two
secondary nutrients usually fairly well supplied in Maryland
soils. The calcium is fast-acting. Also recommended to tie-up
excess magnesium. Will leach sodium from soils with high
salt concentrations caused by de-icing materials or ocean
spray. Gypsum will not raise or lower soil pH.
Humus*: the stable, end product of the decomposition of
soil organic matter. It holds water and nutrients, aids soil
aggregation, is a source of humic acid and chelates, and
contains huge microbial populations. May be purchased.
Humic acid*: an important component of organic matter. It’s
a very mild acid released in the decay process. Dissolves soil
minerals, especially phosphorus, for plant use.
LeafGro*: composted leaves and yard debris from central
Maryland. Approximate analysis 1-.5 -1, with a pH range of
6.8-7.2. Holds 225% of its weight in water and does not repel
water when dry as peat moss does. Use as a soil amendment,
mulch, potting mix component, or top-dressing when seeding
turf. Good peat moss substitute.
Coverage
3 cubic feet of organic matter will cover 36 sq. ft. to a
depth of 1 inch.
Useful conversions: 7.5 gallons = 1 cu. ft.
1 cu. ft. = 1.25 bushels
27 cu. ft. = 1 cu. yd.
Use Manures Wisely
Apply uncomposted manure in the Fall only. Mix into
the top 4-6 inches of your soil; don’t leave it on top
of the ground. Never use pet manure in the vegetable
garden. Fully composted manure can be mixed into
garden soil in Spring.