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Plant Nutrition
Plants need 17 elements for normal growth. Carbon,
hydrogen, and oxygen are found in air and water. Nitrogen,
potassium, magnesium, calcium, phosphorous, and sulfur are
found in the soil. These six elements are used in
relatively large amounts by the plant and are called
macronutrients. There are eight other elements that are used
in much smaller amounts and are called micronutrients, or
trace elements. The micronutrients, which are found in the
soil, are iron, zinc, molybdenum, manganese, boron, copper,
cobalt, and chlorine. All 17 elements, both macronutrients
and micronutrients, are essential for plant growth.
Macronutrients
| Deficiencies
| Remarks |
Nitrogen (N) - Part of proteins, enzymes,
chlorophyll, and growth regulators. | Reduced
growth, yellowing (chlorosis), reds and purples may
intensify with some plants, reduced lateral breaks. | Excess will yield all leaf and stem growth, with
little fruit. |
Phosphorus (P) - Role in fat, carbon,
hydrogen, and oxygen metabolism; respiration and
photosynthesis. | Reduced growth, color may
intensify, foliage turning brown or purple in some plants;
thin stems, loss of lower leaves, reduced flowering. | In very acid or alkaline soils, phosphorus will
be unavailable. |
Potassium (K) - Important in starch
formation, sugar translocation, water relations, disease
resistance, chlorophyll development, and tuber formation. | Reduced growth, shortened internodes, marginal
burn or brown leaf edges, dead spots in the leaf, reduction
of lateral breaks, and tendency to wilt readily. | Large amounts of potash are needed by most
plants. |
Magnesium (Mg) - Part of chlorophyll,
enzyme activator; important in energy utilization. | Reduction in growth; yellowing between veins,
also can occur with middle or lower leaves; reduction in
seed production. | Interferes with calcium
uptake if used in excess. |
Calcium (Ca) - Important in cell wall
structure, cell division, enzymes, and as an enzyme
activator. | Inhibition of bud growth, death of
root tips, cupping of mature leaves, weak growth. | Too much calcium will result in high pH, causing
many of the micronutrients to become unavailable to the
plant. |
Sulfur (S) - Part of protein, amino
acids, vitamins; important in respiration. | Symptoms are a general yellowing of the affected
leaves of the entire plant. | In some places, acid
rain discharges 10 pounds of sulfur per acre to the soil
each year. |
When you're providing those extra nutrients for your
plants, be sure to measure fertilizers accurately and apply
them safely. Fertilizer run-off ends up in nearby streams
and ultimately upsets the water quality in your community.
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January: Understanding Fertilizers
Fertilizers are not plant food! Although it is common
practice to call them plant foods, this is a misnomer.
Plants produce their own food using water, carbon dioxide,
and energy from the sun.
Plant nutrients consist of 17 elements essential to plant
growth. Nitrogen, phosphorous, and potassium are considered
fertilizer macronutrients because plants require them in
larger quantity for maximum growth.
Fertilizer Analysis
All fertilizers are labeled with three numbers. These three
numbers give the percentage by weight of nitrogen (N),
phosphate (P2O5), and potash
(K2O). Nitrogen is important for leaf and stem
growth and provides the rich green color in a plant.
Phosphorous (derived by the plant from phosphate) provides
for root and flower growth. Potassium (derived by the plant
from potash) helps build plant tissue and aids the
production of chlorophyll.
A fertilizer is said to be complete when it contains
nitrogen, phosphorus, and potassium. Examples of commonly
used fertilizers are 10-10-10, 16-16-16, 20-10-5. An
incomplete fertilizer will be missing one of the major
components.
Slow-release fertilizers release nutrients (make them
available to the plant) over an extended period. Caution is
needed when slow release fertilizers are applied around
trees or shrubs, as the later nutrient release may keep the
plants growing into the fall when they should be hardening
off for the winter.
Cottonseed meal, blood meal, bone meal, hoof and horn
meal, fish emulsion and all manures are examples of organic
fertilizers. Organic fertilizers usually contain relatively
low concentrations of actual nutrients, but they perform
other important functions which the synthetic formulations
do not. These functions include: increasing organic content
of the soil, improving physical structure of the soil, and
increasing bacterial and fungal activity.
Effects of Over-Fertilizing
Fertilizers are salts, much like our familiar table salt
except that they contain various plant nutrients. If tender
plant roots are close to the fertilizer granules, water is
drawn from these roots. Plant cells in these roots begin to
dehydrate and collapse, and the plant roots are "burned" or
dried out to a point where they cannot recover.
It is important to apply fertilizer according to
instructions at the proper time and rate to prevent water
quality problems. Avoid getting fertilizer on sidewalks
and driveways where it can easily wash into storm drains
and, eventually, into creeks, streams, and rivers.
Nutrients, particularly nitrogen, become a water quality
problem through leaching or run-off. Leaching is the effect
of nutrients being washed through the lower soil layers and
into the groundwater supply. Leaching and run-off not only
rob your soil of nutrients, but also lead to erosion.
Provide your soil with holding power by planting
groundcovers in bare spots.
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February: Erosion Control
Soil erosion is a major consequence of storm run-off from
unprotected areas. Sediment constitutes the largest volume
of contaminant carried by run-off. Most of the phosphate and
pesticides polluting our waterways are attached to soil
particles. Therefore, controlling erosion will make a
significant contribution to the control of water pollution.
The erosion process is initiated when the impact of
falling raindrops or irrigation water detaches soil
particles. When there is too much water to soak into the
soil, it fills surface depressions and begins to flow. With
sufficient velocity, this shallow surface run-off carries
away the detached soil particles.
Signs of Erosion
- Tree roots, small stones or rocks becoming exposed.
- Small rills or gullies beginning to show.
- Build-up of silt in certain low areas.
- Soil splashed on windows and outside walls.
- The widening or deepening of stream channels.
This destructive process can be controlled by reducing
the quantity and velocity of run-off through the use of
groundcovers. Groundcovers include any plant material that
covers the ground surface so that the soil cannot be seen
from above and rain does not strike directly upon it.
Turfgrass is one important type of groundcover, but many
other low-growing plants are used this way. These include
herbaceous perennial plants and low shrubs. Besides
controlling erosion on slopes, the groundcovers fulfill
other important functions as follows:
- Conserve soil moisture and lower soil temperatures
during periods of extreme heat.
- Utilize nutrients in the soil for plant growth, which
otherwise could be lost to erosion and leaching.
- Reduce lawn maintenance and fill narrow, odd shaped
areas where mowing and edging might be difficult.
- Obstructing foot traffic without impeding view.
- Producing interesting patterns with variation in height,
texture, and color.
Significant maintenance is necessary for the first one to
three years until the groundcover becomes established.
Provide regular cultivation, use organic mulch to control
weeds, and fertilize to encourage vigorous growth for good
cover; irrigate in times of drought; and provide disease and
pest control.
Sod is the most common groundcover. The fibrous roots of
turf grasses firmly hold the surface soil and absorb water.
Sod also benefits the soil by adding organic matter to
improve soil structure and infiltration of water and air.
Newly cut banks and any slopes greater than 12% are best
treated with groundcover plantings other than sod, to reduce
maintenance. Around buildings, ground covers are superior
to paving or structural controls for reducing heat, glare,
noise and dust.
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March: Enhance Your Lawn Health
Bagging grass clippings and throwing them out with the trash
robs your lawn of valuable nutrients. Grass clippings from a
properly mowed lawn are a fertilizer resource. Left on the
lawn after mowing, the clippings reduce the amount of
fertilizer needed for a healthy lawn and reduce the
potential for fertilizer to move into the water system.
Leaving grass clippings on the lawn also saves your local
government the cost of disposing of them at area landfills.
During peak growing periods, usually in April or May, it may
be necessary to collect grass clippings. If you must gather
up the clippings, add them to your yard's compost pile for
later use as mulch.
Soil Test
Before you plant grass seed or fertilize your lawn, pick up a
soil test kit from your local Extension Office, dig up
a soil sample, and have it tested. The soil
report will tell you in plain language whether you need to
apply lime to restore the soil's natural chemical balance.
It will also tell you what kind of fertilizer is needed and
how much you should use. The cost for the test is $7.00.
Mow Regularly
Proper mowing is as important to the success of a well-kept
lawn as any other step. Although recommended cutting heights
vary by type of grass, a good "rule of thumb" is to cut off
no more than one-third of the grass plant at any mowing. Set
the mower height accordingly, but no lower than 1-1/2
inches. Weekly mowing should be often enough except in April
and May, the months of peak grass growth.
Fertilize in the Fall
Fall fertilizer applications are most beneficial to cool
season lawn grasses. Apply the amounts of
lime and fertilizer nutrients (nitrogen, phosphorus and
potassium) recommended in your soil test report.
Applications of fertilizers containing nitrogen should be
made from September through December. By leaving grass
clippings on the lawn, it is estimated that you will reduce
nitrogen applications 20% to 30% after the first year and
35% to 45% after the second year.
Water as Needed
Except during the most severe drought, grasses will survive without watering.
If you wish to maintain a green yard in dry weather, add about 1 inch of
water a week, preferably in the early morning and only as
much as will soak into the ground. Water that is allowed to
run off carries with it nutrients that are valuable to the
lawn but harmful to streams and reservoirs.
By following these guidelines, homeowners can
expect to save money on fertilizer as well as plastic trash
bags. Annual homeowner savings for a typical quarter-acre
lot amount to $20 to $45 in fertilizer costs and $20 to $40
for plastic bags. In addition, you will help your local
government keep a lid on refuse disposal costs. A typical
quarter-acre lot generates 3,500 to 4,000 pounds of grass
clippings a year. Disposing of them costs the homeowner $50
to $90 a year in public service charges, private collector
fees, or taxes.
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April: Tilling the Soil
Tilling your garden correctly preserves the soil and its
fertility, enhancing the absorption of rainfall and
protecting local streams from run-off sediment.
Gardeners often wonder whether to do the plowing or
tilling in the spring or in the fall. Working the soil in
fall is far more beneficial than traditional spring plowing.
It allows earlier spring planting, since the basic soil
preparation is already done when spring arrives. The turning
under of large amounts of organic matter is likely to result
in better decomposition when done in the fall, since autumn
temperatures are higher than those of early spring, and
there is more time for this process to take place. Insects,
disease organisms, and perennial weeds may be reduced by
killing or inactivating them through burial or root exposure
to harsh winter weather. Also, snow is trapped between the
hills of roughly-plowed soil, so more moisture is retained
than on flat, bare ground. Incorporation of limestone or
rock fertilizers in the fall gives them time to interact
chemically with the soil and influence spring plant growth.
Fall plowing alone is not recommended for hillside or
steep garden plots, since soil is left exposed all winter,
subject to erosion when spring rains come. For these areas,
a winter cover crop is grown to improve soil and prevent
erosion. Till in the fall to prepare the soil for seed, and
in the spring turn under the green manure. Spring plowing is
better for sandy soils and those where shallow tilling is
practiced. Generally, most gardens must be lightly tilled in
the spring to kill weeds and smooth the soil for planting.
An alternative to standard procedures is minimum-till
gardening, also known as conservation tillage. This method
is ideal for transplants to the vegetable garden.
- In the fall, prepare the soil for cover crop seed by
tilling under summer crop wastes. Remove tomato vines and
corn stalks to make tilling easier.
- Plant a combination cover crop of rye-hairy vetch (2
lbs. of winter rye grain and 3/4 lb. of hairy vetch per 1000
square feet). The rye, a non-legume, provides the mulch for
spring planting. Hairy vetch, a legume, contributes
beneficial nitrogen to the soil. The vetch seed must be
coated with a Rhizobium inoculant prior to seeding to insure
nodulation with nitrogen-fixing bacteria.
- In the spring, use a scythe or string-line trimmer to
cut the crop cover to a manageable level. Rake the cover
crop to the side of the area to be planted and save. Use a
lawn mower to completely trim to the ground.
- A week later, mow the area again. Now your area is ready
for planting. Dig a hole for each plant, large enough to
accommodate for root spread. Pull weeds in the surrounding
area including cover crop roots. Water in the plants with a
water-soluble fertilizer according to directions or, if
available, put a quart of compost in each hole with the
plant. Mulch the entire area between plants with the
clippings reserved from the week before. Leave 6 to 8 inches
of space around the base of plants to allow the soil to warm
up.
- Some additional mulch may be needed for proper weed
control. Use grass clippings or leaves saved from the
previous fall. If weeds appear, pull them by hand. If hoeing
is needed, try to keep the blade underneath the mulch layer
and disturb as little as possible.
- This process is repeated the following fall to continue
minimum-till gardening. You may want to experiment with
small plots rather than your entire garden.
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May: Fertilizing Your Vegetable Garden
Fertilizers are designed to supplement the nutrients already
present in your soil. Too much fertilizer can damage roots,
and the excess can reach your local stream, leading to water
pollution problems.
Timing of Fertilizer Application
Some crops require more of some nutrients than others. Root
crops require less nitrogen fertilization than leafy crops.
Corn is a heavy feeder and may require nitrogen
fertilization every four weeks. A general rule of thumb is
that nitrogen is for leafy top growth; phosphorus is for
root and fruit production; and potassium is for cold
hardiness, disease resistance, and general durability.
Proper use of nutrients can control rate and character of
plant growth. Nitrogen is the most critical nutrient in
this regard. If tomatoes are fertilized heavily with a
nitrogen fertilizer into the summer, the plants may be all
vine and no fruit. This is also the case with potatoes,
which will show excess vining and poor tuber formation. If
slow-release fertilizers or heavy amounts of manure are used
on crops that form fruit or vegetables, the plant will keep
producing leaf or vine growth, and fruit or vegetable
development will occur very late in the season.
Remember that a nitrogen application will have its
greatest effect for three to four weeks after application.
If tomatoes are fertilized heavily on June 1, there may be
no flower production until July 1, which will delay fruit
ripening in late August. For this reason, it is important
to plant crops with similar fertilizer needs close together
to avoid improper rates of application.
Application Methods
Broadcasting. A recommended rate of fertilizer is spread
over the growing area and left to filter into the soil, or
incorporated into the soil with a tiller or spade.
Banding. Narrow bands of fertilizer are applied in
furrows 2 to 3 inches from the garden seeds, and 1 to 2
inches deeper than the seeds or plants that are to be
planted. If the fertilizer band is placed too close to the
seeds, it will burn the roots of the seedlings. For plants
widely spaced, such as tomatoes, fertilizers can be placed
in bands 6 inches long for each plant, or in a circle around
the plant. Place the bands 4 inches from the plant base.
Banding is one way to satisfy the needs of many plants
(especially tomatoes) for phosphorus as the first roots
develop. When fertilizers are broadcast and worked into the
soil, much of the phosphorus is locked up by the soil and is
not immediately available to the plant. By concentrating
the phosphorus in the band, the plant is given what it
needs, even though much of the phosphorus stays locked up.
Side Dressing. Dry fertilizer is applied as a side
dressing after plants are up and growing. Scatter
fertilizer on both sides of the row, 6 to 8 inches from the
plants. Rake it into the soil and water thoroughly.
Foliar Feeding. Nutrients applied to foliage are
absorbed and used by the plant quite rapidly. Absorption
begins within minutes after application, and with most
nutrients, it is completed within 1 to 2 days. Foliar
feeding is best when your soil is too cold for the plants to
extract the dry fertilizer. Foliar nutrition can be a
supplement at a critical time for the plant, but cannot
replace soil fertilization.
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June: Irrigation
Adequate soil moisture is essential for good crop growth. A
healthy plant is composed of 75-90% water, which is used for
the plant's vital functions, including photosynthesis,
support (rigidity), and transportation of nutrients and
sugars to various parts of the plant.
There are several options for applying water to plants.
These include: a watering can, a garden hose with a fan
nozzle or spray attachment for containers, small gardens or
individual plants and portable lawn sprinklers, a perforated
plastic soaker hose, drip or trickle irrigation, or a
semi-automatic drip system for lawns and gardens.
Your careful use of irrigation techniques will help local
streams and will ultimately benefit larger bodies of water
in your surrounding area by reducing fertilizer and
pesticide(if you find yourself using it even with the best of intentions!)
run-off and by conserving water.
Some Basic Techniques and Principles for Watering
- Adjust the flow or rate of water application to about
one-half inch per hour to avoid causing run-off. To
determine the rate for a sprinkler, place small tin cans at
various places within the sprinkler's reach, and check the
level of water in the cans at 15-minute intervals.
- When using the oscillating type of lawn sprinkler, place
the sprinkler on a platform higher than the crop to prevent
water from being diverted by plant leaves. Try to keep the
watering pattern even by frequently moving the sprinkler and
overlapping about one half of each pattern.
- Do not sprinkle foliage in the evening. Wet foliage
overnight may encourage disease. Morning watering is
preferred.
- Perforated plastic hoses or soaker hoses should be
placed with holes down (if there are holes), along one side
of the crop row or underneath mulch. Water will slowly soak
into the soil.
- Frequent, light waterings will only encourage shallow
rooting, causing plants to suffer more quickly during
drought periods, especially if mulches are not used. On the
other hand, too much water, especially in poorly drained
soils, can be as damaging to plant growth as too little
water.
Your lawn can use an inch or more of water per week in
hot, dry weather. The lawn should be watered when the soil
begins to dry out, but before the grass actually wilts.
Loss of resilience can be observed; footprints will make a
long-lasting imprint instead of bouncing right back.
Critical watering periods for selected vegetables are:
Asparagus | Spear production, fern development |
Broccoli, Cabbage, Cauliflower | Head
development |
Beans, Peas | Pod filling |
Carrot | Seed emergence, root development |
Corn | Silking, tasseling, ear development |
Eggplant, Tomato | Flowering, fruiting |
Cucumber, Melon | Flowering, fruit development |
Lettuce | Head development; moisture should be
constant |
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July: Reducing the Effects of Drought
One of the times you are most counted on is during a
drought. Follow guidelines for local water restrictions, if
applicable. By your participation, you contribute to water
conservation efforts and water quality in your area.
What happens to soil nutrients during a drought? The good
news is - nothing. It does not change soil composition or
structure. The nutrients are not lost or evaporated from the
soil.
But heavy rainfall after a dry period can wash away heavy
clay, and with the clay go your valuable nutrients and
topsoil. This is not caused by the drought, but by the
structure of clay soil; it is made up of very small
particles which are easily dispersed by water. This leads to
erosion and nutrient loss. There are several ways to hold on
to your soil and improve nutrient quality:
- Incorporate organic matter into clays and other soil
types to improve soil structure.
- Mulch to conserve moisture and control soil splashing.
- Use trickle irrigation near the base of plants to reduce
run-off.
Watering
There is no substitute for water during a dry spell. The
correct time to water has always been a controversial issue,
and the proper time to water a garden or lawn may be a bad
time for most working people. Using a timed irrigation
system is one of the best ways to conserve water and time,
but for those who don't want to make that kind of
investment, there are some general tips to follow:
The best watering time is early morning, when humidity is
high and moisture loss is minimal.
Afternoon watering should be avoided. Irrigating during
the day results in a 20-25% loss of water through heat and
evaporation, and if foliage is watered, it can create a
magnifying-glass effect that will burn leaf tissue. If a
plant shows signs of drought stress in the afternoon, do
apply water, but at the base of the stem.
Watering in the evening conserves water as well, but it
increases the risk of fungal disease and damage from
nocturnal insects searching for water.
Dormancy or Death
With sparse rainfall, the least of your worries is your
lawn. Mother Nature has provided the grass plant with a
built-in protection plan - dormancy. The lawn will turn
brown as moisture reserves dry up, but it is far from dead.
By going into a dormant state deeper than its winter
dormancy, the grass plant halts the process of
photosynthesis. Production of new growth is arrested. This
also explains why grass grows at a slower pace in hot, dry
periods. When rains do come and drought stress ends, the
grass will green up, especially fescues, bluegrass, Zoysia,
and Bermuda grass.
Restrict the use of herbicides because it tends to stress
the lawn as it tries to detoxify the chemical. And when a
lawn becomes brown during a dry spell, the last thing that
is needed is fertilizer. Application of fertilizer at this
time can kill your lawn. It's like telling someone who has
just finished running a full marathon to run another ten
miles.
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August: Improving Your Soil
Applied correctly, a soil amendment conserves moisture,
improves infiltration of rain or irrigation water, and
"unlocks" existing nutrients in the soil. With this
practice, nutrients are more readily absorbed into the soil
and less run-off takes place.
Any addition to the soil which improves its physical or
chemical condition is considered a soil amendment. Many
types of amendments are available to the gardener.
Amendments to Change pH and Nutrient Levels
The correct soil pH is essential for optimum plant growth.
Lime and sulfur are common amendments used to balance soil
pH. Dolomitic limestone adds calcium and magnesium as it
increases pH, making the soil more alkaline. Elemental
sulfur will acidify soil. The amount of amendment to add
depends on the current and desired pH - one good reason to
have garden soil checked periodically.
Amending the soil with wood ashes raises soil pH, but you
must apply twice as much ash as limestone for the same
effect. Spread it in a thin layer and incorporate it into
the soil. Check pH yearly if you use wood ashes. Never use
coal ashes or large amounts of wood ash (no more than 20
pounds per 1000 square feet), as toxicity problems may
occur.
Other amendments are added specifically to improve soil
nutrient levels. Greensand and granite meal are sources of
potassium. Granite meal is finely ground granite rock which
releases its potassium slowly. Greensand is relatively low
in potassium, which is readily dissolved. Other nutritional
amendments that can be purchased for garden use include
cottonseed meal, kelp meal, leather meal, and worm castings,
as well as an array of synthetic fertilizers.
Amendments to Improve Soil Qualities
The regular addition of manures, compost, cover crops, and
other organic matter can raise the soil nutrient and
structure level to a point at which the addition of
synthetic fertilizers is greatly reduced, and in some cases,
no longer needed. This highly desirable soil quality does
not come about with a single or even several additions of
organic material, but rather requires a serious, long-term
program.
Animal manures are commonly used as a garden soil
amendment. Fresh horse, sheep, rabbit, and poultry manures
are quite high in nitrogen and may burn plants if applied
directly to a growing garden. They are best applied in the
fall and tilled under.
The use of compost is one way to get around tying up
nitrogen during decomposition. Compost is usually made by
the gardener from plant wastes. Correct composting can
result in a valuable nutrient and humus source for any
garden. The basis of the process is the microbial
decomposition of mixed, raw, organic materials into humus -
a dark, fluffy product resembling rich soil - which is then
spread and incorporated into the garden soil.
Check Here for information about building a
compost pile.
Remember, your soil is alive and constantly changing. By
keeping it fertile and rich, many gardening problems may be
diminished. Soil is the base for plant growth, and much
attention should be paid to getting and keeping it in the
best condition.
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September: Protecting Soil in the Winter
The use of cover crops reduces erosion and maintains and
builds nutrients for your garden over the winter.
Turning under vegetation in the fall allows earlier
planting in the spring and is especially good for heavy
soils, since they are exposed to the freezing and thawing
that takes place during the winter. This helps to improve
soil structure. A cover crop's roots hold the soil,
decreasing erosion during the winter. Tilling under the
cover crop in the spring adds organic material to the soil,
improving its structure and porosity and adding valuable
nutrients. Winter cover crops can be planted from September
1 through November 1 (optimum planting is September 1 to
October 15). Where you have fall crops growing, you can sow
cover crop seed between rows a month or less before expected
harvest. This way the cover crop gets a good start but will
not interfere with vegetable plant growth.
Some cover crops suitable for winter use are legumes such
as crimson clover, fava beans, or hairy vetch. Non-legume
cover crops such as barley, winter rye, or winter wheat may
also be used with good results. Mixtures of legumes and
non-legumes are effective as well. Ask at the seed store or
your local Extension office what the best type of cover crop
for your area is, and at what rate (pounds per 100 square
feet) to plant it.
Prepare the soil for cover crop seed by tilling under
plant wastes from the summer. Broadcast the seed, preferably
before a rain, and rake it evenly into the soil. Spring
planting may be delayed somewhat by the practice of cover
cropping, since time must be allowed for the green manure
cover crop to break down. If you have crops that need to be
planted very early, you may prefer to cover a section of the
garden with mulch.
Other Practices
Some gardeners are experimenting with various types of
conservation-tillage gardening to reduce weed problems and
prevent erosion and moisture loss. The standard no-till
practice used on farms involves sowing a fall cover crop,
killing it in the spring with an herbicide, such as
paraquat, and planting vegetables in the dead sod (after a
recommended waiting period). However, there are no emergent
weed herbicides recommended for use in established home
vegetable gardens at the present time. Use of weed-killers
normally recommended for lawns or other areas is not
advised, and until a safe herbicide is available for
emergent weeds, this type of no-till practice is unsafe for
growing vegetables in the home garden.
Another alternative is the use of a living sod, mowed
regularly, which has many of the benefits of no-till and
does not necessitate the use of herbicides. This practice
works best with raised beds, so that only the paths need to
be mowed.
Dr. John Luna at Virginia Tech reports success using a
combination of winter rye and hairy vetch as a fall-sown
cover crop, harvesting it with a scythe in the spring,
planting through the stubble, then using the top material as
a mulch as the season progresses. Also, this option does
not require herbicides.
The use of cover crops over several seasons or years in a
particularly weedy section of the garden is particularly
useful in reducing weed problems and water demand.
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October: Test Your Soil
The amount of fertilizer, lime, and other amendments
recommended for soil improvement should allow optimum growth
without undue risk of polluting the natural run-off. It is
important not to apply more than is recommended, and if time
of year or season of application is a part of the
recommendation, these guidelines should also be closely
followed. This will assure greatest plant response with the
least chance of plant damage or drainage water pollution.
Fertilizer, lime, and other amendments washed off by heavy
rains contribute to stream pollution.
The purpose of a soil test is to supply you with enough
information to make a wise fertilizer and soil amendment
choice. A soil test will provide
information on pH, available phosphorus, potassium, calcium,
and magnesium. Soluble salts are run on request. The
results of the soil test are mailed to you with
recommendations as to what kind of fertilizer or amendment
should be applied for economical growth of the desired crop
or specific plant. A soil test need not be performed more
often than every three to four years. Submit your sample in
the fall, prior to planting or tilling, so that needed lime
or other soil amendments can be changing the pH over the
winter. Fertilizers should be incorporated the next spring.
Soil test kits are available for checking soil at home.
For best results, carefully follow the instructions given
for the soil test. Private companies also do soil testing;
these give detailed reports and recommendations in many
cases, but may be expensive ($30 is not unusual).
The accuracy of the test is a reflection of the soil
sample taken. Be sure your sample is representative of the
area to be treated. Sample the soil from 10 random areas to
the depth at which you till the garden. Avoid sampling
unusual areas such as those near gravel roads, manure or
compost spots, brush piles, or under eaves. Place the
samples in a clean pail or container and mix the soil
thoroughly, then transfer one cup of mixed soil to a
container and take it to your local Extension Office. The
results will be mailed to you with recommendations for
correcting any deficiencies or other problems that may
exist.
Soils range greatly in their properties and in their
suitability for different uses. Many of the differences in
soils relate to the geologic parent materials and the local topography.
The main soil types are sand, clay, silt, and loam. Sandy
soil feels very coarse and grainy. Water drains through it
very quickly. As a result, sandy soil dries out rapidly.
Clay soil is very thick, like putty. It holds water like
a sponge. Clay soil does not dry out as fast as sandy soils,
but when it does dry out, it becomes hard and very solid,
making it quite difficult to break the soil surface with a
shovel.
Silty soil is between sandy and clay soil. It holds water
well but does not dry into a hard, solid mass.
Loam is the ideal mixture of sand, clay, and silt.
Through the addition of organic amendments, loam can become
the perfect soil for your vegetable garden.
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November: Uses for Leaves
If you're lucky enough to have large trees adorning your
property to provide cooling shade through the summer, you
may consider yourself less fortunate in the fall, with all
those leaves to be raked, bagged, and carted to the local
landfill.
This year, try a different strategy. Instead of turning
those leaves into garbage, turn them into a beneficial soil
amendment for next year's flower and vegetable beds. Autumn
leaves can be added to the home compost pile or used as
mulch.
A compost pile need not take up a large part of your lawn
or garden. Nor does a properly maintained compost pile have
offensive odors. To contain the compost, use a 3- or 4-sided
structure made of wood or wire meshing. Add any vegetable
matter to it, such as kitchen discards and the autumn
leaves. It's a good idea to add an occasional layer of soil
and some ground limestone to aid the decomposition process.
Turn the compost occasionally. By next gardening season,
you'll have rich, dark compost that makes an excellent
amendment to soil.
If you need only a small amount of compost, you can use a
plastic trash bag to compost relatively fine material such
as shredded leaves, lawn clippings, or chopped garden
refuse. Make layers as in a compost pile, or mix all
materials together. Add 2 quarts of water to dry material (1
quart if it is quite moist or succulent). Tie the bag and
turn it over monthly to aerate the material and distribute
the moisture.
A lawn mower can be used to shred leaves. Pile the leaves
a few inches high and go over them several times with the
mower. Shred leaves when they are dry, to prevent blades
from clogging. Shredded leaves are great to incorporate with
other materials for compost making, but less effective for
mulching purposes as they decompose too quickly.
Can you compost or mulch with leaves that carry disease
or insects? The answer is a qualified yes. Diseased or
insect-infested leaves should be used as a mulch for flowers
or shrubs, not other trees. This way, even if the leaves
carry disease, they won't damage other trees. If the leaves
seem very infected, it may be wiser to compost them, since
this can destroy many harmful organisms.
Other Valuable Uses
- In the fall, collect leaves in bins or large piles. In
spring, dig into the pile to get the matted clumps of
partially decomposed leaves. Use as a mulch to keep moisture
and nutrients accessible to the plant.
- Fill the paths between raised beds now, for fewer weeds
next spring.
- Till into the soil in fall to break down by spring.
- Fill bags with leaves and use as insulation for cold
frames.
- Use as a winter mulch on bare ground to reduce erosion.
Leaves are an excellent source of organic matter and
other nutrients. The more you can add to a compost pile or
use as a mulch, the less goes into an already over-used
landfill. Mulching can also make the soil more workable, aid
rainwater penetration, and improve moisture retention near
plant roots.
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December: Winterizing Trees and Shrubs
By safeguarding your established trees and shrubs for
winter, you help minimize the damage caused by surface
run-off and erosion and subsequent water pollution.
It is often necessary to give a little extra attention to
plants in the fall to help them make it through winter and
start spring in peak condition. Utilize cultural practices
that will help you reduce winter damage of ornamentals.
Select hardy plants. Grow plant materials that are
native or are known to be winter-hardy in your area.
Select an appropriate site. Some varieties of
rhododendron, azalea, camellia, daphne, and holly need a
location on the north, northeast, or eastern side of a
building or other barrier where they will be protected from
prevailing winds and intense winter sun.
Avoid poorly drained soil, low spots that create frost
pockets, and sites that are likely to experience rapid
fluctuations in temperature.
Practice late fall fertilization. Fertilize after plants
are dormant but before soil temperature drops below
45o F. to help prevent winter damage. Avoid late
summer or early fall fertilization while plants are still
active, as this stimulates late fall growth which is easily
killed by freezing.
Prune at the right times. Proper pruning at appropriate
times throughout the year is effective in reducing damage by
ice and snow. Avoid late summer pruning, which stimulates
new, tender growth and reduces the supply of nutrients
available to the plant through the winter.
Be sure your plants have enough water. Proper watering
can be a critical factor in winterizing. If autumn rains
have been insufficient, give plants a deep soaking that will
supply water to the entire root system before the ground
freezes. This practice is especially important for
evergreens. Watering during January, February, and March,
when there are warm days, is also important.
Mulch to control erosion, soil temperature, and loss of
water. A 2-inch layer of mulch material such as fir bark,
pine needles, or wood chips will reduce water loss and help
maintain uniform soil moisture around roots. Mulching also
reduces freezing and thawing of the soil which heaves some
shallow-rooted plants, causing significant winter damage.
Remove snow that is collecting on branches with a broom.
Always sweep upward with the broom to lift snow off. When
the branches are frozen and brittle, avoid disturbing them.
Wait until a warmer day.
Protect newly planted trees. Bark splitting, especially
dangerous on young trees, is caused by the extreme
fluctuations in temperature. The afternoon sun on exposed
trunks raises the temperature much higher than the air and
the sudden drop at dark causes splits and cracks. It can be
prevented by wrapping trunks with burlap strips or a
commercial tree wrap or shading the southwest side.
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Nutrient Management and Its Impact on Water Quality
Practicing good cultural methods and nutrient management has
many benefits. This calendar is filled with tips that are a
reminder of the ways you can help preserve water quality
while helping your plants achieve optimum health and
production. Watch for more information on such ideas as:
Don't bag those clippings! Returning clippings will
return nutrients to your lawn.
Build a compost pile and you convert trash to treasure.
Such throwaways as leaves, grass clippings, and fruit and
vegetable scraps decompose into priceless organic matter.
Mulch to conserve water; during a drought, it can mean
the difference between life and death to your plants.
Control erosion with the use of cover crops and
groundcovers.
Use proper irrigation equipment, such as soaker hoses and
water timers, to reduce water consumption.
Test soil for accurate nutrient formulation for a
specific plant. The test will provide you with information
on pH, available phosphorus, potassium, calcium, and
magnesium.
Use correct tilling procedures to lessen erosion. Tilling
in the fall allows earlier spring planting, better
decomposition of organic matter, and less chance for
diseases, insects, and weeds since turning the soil over
exposes these pests to harsh winter weather.
Mow at the proper height to protect the grass plant from
stress and to preserve moisture. A good "rule of thumb" is
to cut off no more than one-third of the grass plant at any
mowing.
Using these and other methods from this calendar will
provide:
- Reduced costs for you
- Reduced landfill dumping
- Reduced maintenance time
- Increased water quality
Active use of these methods enables you to become an
expert in your own environs and steward of clean water. For
more information, contact your local Extension office for
slide and video programs and publications available on
nutrient management and its impact on water quality.
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