This document provides information about analyzing soil for a Massachusetts school garden. It describes 6 tests that can be done to understand the soil: 1) Determine the soil type on a map, 2) Examine the soil profile and layers, 3) Look at soil color, 4) Determine soil texture, 5) Check soil nutrients and pH levels, and 6) Test for organic matter content. The results of these tests can be used to create a soil improvement plan tailored to address any issues found, such as low organic matter, poor drainage, or lack of certain nutrients. Understanding the soil conditions is important for having a healthy, productive garden.
1. Soil in the Massachusetts School Garden - Massachusetts Agriculture in the Classroom 2012
Taking care of your soil is perhaps the most important factor in your school garden. This how-to guide includes
a background on soil formation, and then six different tests that you can conduct with children to analyze and
understand your garden soil. This is followed by six techniques you can use to improve your soil based on those
findings.
Background: Soil Formation
The soil is a mixture of living and non-living components,
organic and mineral. It is formed through the action of
parent material, climate, plant, insect and animal life, in
different topographical locations over time. The relative
influence of each of these factors differs in different
locations.
Parent Materials are the minerals that break down to form
soil. Much of this is from hard rocks such as granite. These
parent materials may be derived from the bedrock that is
directly below a soil, or the soil may be composed of an
entirely different mineral that has been transported from a
different location. In this case, glaciers may have moved
rock fragments and earthy materials, or the minerals may
have been deposited by water as sediment along rivers and
streams, in the flooded bottomland of existing streams, out
of the still water of historic lakes or deposited by tides from
the sea. Wind and gravity can also move soil.
The kind of climate under which a soil forms largely
determines the nature and the rate of physical and chemical
weathering of these parent materials. Wind or rain may
weather rock surfaces, breaking down the rock and adding
those minerals to the soils. Cold wet winter temperatures
cause frost action, which also breaks apart rock fragments.
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Soil in your Massachusetts School Garden
Insert 1.
Massachusetts Soils
Massachusetts was covered with glacial ice
12,000 to 14,000 years ago. The parent
material of the most extensive soils in our state
are comprised of various types of glacial
deposits. These soils have weathered little
compared to soils in non-glaciated areas and
have developed relatively weak soil profiles.
Some Massachusetts soils were deposited
beneath advancing or retreating glaciers.
These are dense, firm sandy loams. Other soil
were deposited by melting ice. These tend to
be coarsely textured, sand, gravel and stones.
Post glacial winds deposited 1 to 2.5 feet of silt
or very fine sand over glacial sediment in many
areas of Northern Massachusetts.
Along major stream valleys, glacial outwash
deposits consisting of layered sand and gravel
overlain by a more weathered, loamy or sandy
surface layer and subsoil may be found. Low
plains were formed along parts of the present
coast of Massachusetts when ocean levels
receded following glaciation and marine
2. Soil in the Massachusetts School Garden - Massachusetts Agriculture in the Classroom 2012
Glaciation grinds and moves even large rocks. Rainfall can
leach water-soluble minerals down through the soil.
Climate also affects the type of vegetation in an area, which
affects those soil-forming processes related to plant life.
The topography or shape of the land surface, slope and the
position of the soil on the landscape are dominant factors in
soil formation. Soils that formed in identical parent
materials and under the same conditions vary because of
position on the landscape. This is largely the result of
drainage conditions caused by differences in surface runoff
or depth to the seasonal high water table in that location.
Soils formed at higher elevations and in sloping areas
generally are well drained, with six feet or more depth to
ground water. Surface runoff is rapid. In these areas, soil
colors are bright strong brown to yellowish brown in the
subsoil grading to a lighter, grayer unweathered substratum.
On soils at lower elevations, such as those in swales, adjacent to drainage ways and water bodies, and in
depressions, surface runoff typically flows down from higher elevations. The seasonal high water table is often
at a shallow depth. In these areas the soils are somewhat poorly drained and generally have a yellowish brown
color with gray subsoil. In poorly and very poorly drained soils, the seasonal high water table is at or near the
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sediments were left exposed. The sediments
generally are at elevations as high as 50 feet
above sea level and grade gently to sea level.
Moderate temperatures in Massachusetts allow
the accumulation of organic matter in the
surface layer of most soils. Rainfall leaches
water-soluble minerals down through the soil,
resulting in acid soil throughout most of the
state. In winter, cold temperatures and high
moisture cause frost action, which is especially
active in loamy soils not under forest
vegetation. Frost action breaks apart rock
fragments, and in some soils influences soil
structure.
Human activities have significantly altered soil
in some areas. Many soils have a distinct plow
layer formed by mechanical cultivation and
additions of organic matter, lime, fertilizer.
Some naturally wet soils have been altered by
artificial drainage and filing. Throughout the
state, especially in urban areas, there are many
areas where the natural soil has been covered,
removed or replaced by homes, businesses,
recreation and other human activity.
Looking to the future of Massachusetts soils,
soil organic matter is one of the major pools of
carbon in the biosphere and is important both
as a driver of climatic change and as a response
variable to climate change, capable of acting
both as a source and sink of carbon. Soils also
helps regulate other greenhouse gases such as
nitrous oxide and methane.
Photo: Author. Peck School Holyoke MA 2012
3. Soil in the Massachusetts School Garden - Massachusetts Agriculture in the Classroom 2012
surface for pro-longed periods. The soil profile typically has a dark colored organic or organic rich layer and a
strongly mottled or gray subsoil and substratum.
The last element in soil formation is time. It can take as long as five hundred years to make one inch of soil.
The soils of Massachusetts are relatively young and have weathered little compared to soils in non-glaciated
areas.
Tests For Your Soil
Understanding the soil conditions at your school will help you to understand how to work toward healthy soil in
your garden. Determining the specific mineral and organic matter make up determined by soil tests and visual
analysis is helpful. In addition, some basic techniques such as adding compost and mulching, are a good idea
for any Massachusetts soil and will generally be enough to improve a small non-commercial plot.
In addition, finding out the history of your site and determining any hazards like underground utility lines is
important, and figuring out if your soil is contaminated with heavy metals such as lead, is a required step before
creating your school garden.
Test 1: Determine Your Soil Type on a Soil Map
No two soils are exactly the same. Over 18,000 types have been classified so far in the U.S. These are divided
into twelve major orders with suborders, great groups and families, similar to the
taxonomic system used for plants and animals.
There are five main soil types: clay, silt, sand, limestone and peat. Most soils are
a mixture, and their description refers to their major constituent. Soil mixtures
are know as loams: e.g. a soil with a high proportion of sand could be a “sandy
loam”
Go to the website of the USDA’s web soil survey (http://
websoilsurvey.nrcs.usda.gov/app/HomePage.htm) to see a soil map of your area
and find out your soil type. There are instructions on the first page, but I suggest
the following order to make things easier.
On the first page, click the green button that says “Start WSS.” When you get to
the next page, in the “area of interest” tab, I suggest you click on “soil survey
area” and choose Massachusetts and your county. Next click the “scale” button
above the large box where the map will appear, this automatically calibrates the scale. Once a map appears in
the large box, you can then click the “Soil Map” tab, and explore your specific location within this by selecting
smaller areas with the zoom button and moving the map around with the “hand” button. Be patient, this
program is processing a huge amount of data and can be slow. Once you have found your particular location,
you can cross reference the numbers on the map with the soil type in the side bar to determine your soil type.
Clicking here on your soil type will tell you more information such as typical drainage properties, parent
materials and typical profile. It can be interesting to compare this information with what you find with the hands
on tests below.
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4. Soil in the Massachusetts School Garden - Massachusetts Agriculture in the Classroom 2012
Test 2: Look at Your Soil Profile (also called soil horizons)
Soil has three layers. Topsoil, subsoil and bedrock.
Topsoil (also known as the A horizon) is composed of organic matter and mineral matter that formed at the
surface. Most nutrients, organisms and plant roots are located in this layer. A typical topsoil may contain forty-five
percent minerals, twenty five percent air, twenty five percent water and five percent organic matter.
The Subsoil layer (also known as the B horizon) contains minerals that are usually weathered from the original
parent material. It is often found about one foot below the surface. Deeper tree roots and earthworms live here.
The Parent Material is the bottom layer, as much as three feet below the surface in the Northeast. It is more
compact and often has stones and rocks in it.
- Dig a pit with straight sides to a depth of two feet, or until you hit an impenetrable rock layer. (If this is too
hard, consider getting help from other adults)
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Top Soil
Sub Soil
Parent Material
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- Use a tape measure to measure the depth of the different layers. This will be more obvious in some places than
others, but can usually be determined by changes in color.
- Record and diagram your soil layers
How does this help you with your soil improvement plan?
If you have a thin top soil layer, one of you priorities will be to build soil up to a level that can support plants. If
your parent material is close to the surface, you may also need to consider growing more shallow rooted crops
until you have built up the soil in your beds.
Test 3: Look at Your Soil Color
Soil color has little known direct influence on the functioning of the soil, but important soil characteristics can
be inferred from color. The two major coloring agents are organic matter and iron. Organic matter darkens the
soil: as little as 2 to 5 percent can give soil a dark brown to black color. These darker soils are generally
considered to be better and more fertile. Oxidized iron generally makes the soil yellow to reddish in color,
which indicates a well aerated soil, reduced iron makes the soil gray or bluish-green, indicating that it is poorly
drained.
Soil color has a sophisticated classification system in soil science using the Munsell color chart and
distinguishes soils by hue: red, yellow, green, blue and purple, value: degree of lightness or darkness, and
chroma: strength of color. These soil color charts offer 245 different color chips systematically arranged. This
level of analysis is generally not necessary for a small garden, but looking at color can give you a quick method
of determining soil quality when siting your school garden.
How does this help you with your soil improvement plan?
From soil color your can get a sense of the level of organic matter in your soil, and how high a priority adding
organic matter is in your soil improvement plan. It can also help you determine how well drained your garden
is.
Test 4: Determine Your Soil Texture
Soil texture refers to the relative proportions of sand, silt and clay in the soil. Sands are the largest particles and
clays are the smallest. Imagine a piece of sand as the size of a basketball. That would make silt the size of a
baseball and clay smaller than the size of a marble. The basic soil textures are sand, loamy sand, loam, silt, silt
loam, sandy clay loam, clay loam, silty clay loam, sandy clay, silty clay and clay.
Sand particles can be seen with the naked eye and feel gritty. They can be wiped clean from one’s hands with
ease leaving no materials in the pores and fingerprints. They can be further subdivided into size fractions. The
classes of sand are coarse sand, fine sand, and very fine sand.
Silt particles can be seen with a hand lens or light microscope. They have a smooth powdery feel when dry, and
a slick creamy feel when moist or wet. Some liken the feel to that of talcum powder. Silt is not sticky or
plastic. After handling silty soil, a coating will be left on the hand, which for the most part can be brushed off
when dry leaving silt particles in the pores and grooves of your fingerprints.
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6. Soil in the Massachusetts School Garden - Massachusetts Agriculture in the Classroom 2012
Clay particles can be seen only with an electron microscope. Clay is sticky and plastic when wet. It is hard
when dry. After handling clayey soils a film will be left on the hands, the removal of which requires vigorous
washing.
About one half of any soil is made up of pores full of air and water. Plant roots need oxygen from the air in soil
for best root development and growth. Many bacteria also need air.
Plants need water to grow. Water movement in the soil brings better
air circulation. When water enters the soil, air moves out and is replaced by fresher air as soon as the soil pores
are again free of water.
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Photo: Author
Insert 3
Size Classification of Soil
Separates
Soil Separate Size
Very coarse
sand
2.0 - 1.0 mm
Coarse sand 1.0 - 0.5 mm
Medium sand 0.5 - 0.25 mm
Fine sand 0.25 - 0.10 mm
Very fine sand 0.10 - 0.05 mm
Silt 0.05-0.002 mm
Clay Less than 0.002
mm
Gravel 2 mm to 3
inches
Cobbles 3 to 10 inches
Stones 10 inches to 2.5
feet
Boulders greater than 2.5
feet
7. Soil in the Massachusetts School Garden - Massachusetts Agriculture in the Classroom 2012
The amount of open space between soil particles has a lot to do with how easily water moves through a soil and
how much water it will hold. Sandy soils do not hold much moisture since there is less surface area for the
water to cling to, and there are large pores spaces where the weight of the water causes much of it to run down
and out of the soil.
Finer textured soil can hold more water for plants because there is more surface area on which water adheres.
Since the size of the pores is reduced, the weight of the water is less and it doesn’t run out of the soil so readily.
There is however a fine line. Some soils that are high in clay hold a great deal of water, but hold it so tightly
that many plants can not extract the moisture. In general, silt loam soils have the greatest available moisture
holding capacity for plant growth.
Compaction: In compacted soils, the particles that make up the soil are pressed together. Not only is the soil
physically harder, but without air spaces, a root cannot grow or even breathe. These compacted areas may also
be lower than surrounding soils. Not only are the soils squished and compacted, but some of the topsoil may
wash away, because plants are no longer there to hold the soil in place. The areas near human habitats are full of
examples of compacted and overused land. The land near public building or suburban lawns is often heavily
used by people.
- Take a soil sample of about 2 cups from your garden
- Crush any lumps and remove large rocks, sticks or trash
- Take a quart jar and put the soil into it, add water until the jar is 3/4 full
- Screw on the lid tightly and shake vigorously
- Let the jar stand for several minutes.
- You will see that the mixture separates into layers.
The larger particles, such as coarse sand or rocks, will settle to the bottom of the jar. The finer particles of silt
and clay will form the next layer. The material left floating on the top of the water is organic matter.
How does this help you with your soil improvement plan?
Soil texture determines how well drained your soil is. If you have poorly drained or too well drained soil, you
may want to consider adding organic matter such as compost or another soil conditioner.
Test 5: Soil Nutrients and PH.
The bulk of the materials used by the plant to build its own food are hydrogen and oxygen from water and
carbon from carbon dioxide. It also needs in small amounts: nitrogen, phosphorus, potassium, calcium,
magnesium, iron, and sulfur and in minute amounts boron, manganese, zinc, copper and molybdenum. Soil PH
affects which crops will do well in your garden. Unless you are planning to grow a crop like blueberries, which
prefers an acid PH, maintaining a balanced PH of in the neutral range around 7.0 is preferred by most plants.
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8. Soil in the Massachusetts School Garden - Massachusetts Agriculture in the Classroom 2012
Nitrogen keeps the leaves green and helps stems grow. Too little
nitrogen causes stunted growth and yellow leaves. Too much nitrogen
will cause the plant to grow too fast, have poor fruiting, and have
weak, soft stems.
Phosphorus helps plants store and use energy from the sun to make
food for themselves. Phosphorus is important for beautiful flowers,
seed development and general good growth. A phosphorus deficiency
causes small, thin immature plants. Plants need large amounts of
phosphorus as they begin to grow and when the weather turns cold.
Potassium makes plants stronger, the fruit stays fresher and the
grasses greener. Potassium keeps the cells of the plant strong, forming
strong stems and roots. It permits free flow of food through the plant,
produces starches, controls root growth and open and closes pores for
water. Potassium help plants survive droughts, diseases, and very hot
and cold temperatures. Potassium is found in the soil but only a small
amount is available to plants.
A soil test can help you determine the ratios of these things in your
soil, as well as giving you your soil PH and lead content. The
University of Massachusetts has a soil testing lab which can be found
at http://www.umass.edu/soiltest/. Ask for their basic test. On the
second page of the soil test submission form there are detailed
instructions on how to take a soil test. Make sure you also specifically test at the drip line of your building if
you plan to grow crops there, as this may be a site of accumulated lead.
How does this help you with your soil improvement plan?
Although compost is always recommended for any soil nutrient make-up, with the findings from a soil test you
can also determine which nutrients to look for in soil amendments and fertilizers, and how much compost you
may need to add. It is also vital in determining lead content.
Test 6: Your Soil Food Web
A spoonful of soil contains more microorganisms than there are people on Earth! The soil food web is the
exchange of energy between different organisms that live on or from the soil. Many different organisms make
up the soil food web, from one-celled bacteria, algae, fungi, and protozoa, to the more complex nematodes and
micro-arthropods, to earthworms and insects.
The plants, lichens, moss, photosynthetic bacteria, and algae that use the sun’s energy to fix carbon dioxide from
the atmosphere. Most other soil organisms get energy and carbon by consuming the organic compounds found
in plants, other organisms, and waste by-products. A few bacteria, called chemoautotrophs, get energy from
nitrogen, sulfur, or iron compounds rather than carbon compounds or the sun.
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Insert 4
Using Weeds as Indicators of
Soil Conditions
From:Weeds and What They Tell, by
Ehrenfried Pfeiffer
Weeds Soil Condition
indicated
Sorrel, dock,
horsetail
Soil is acidic or
increasing in
acidity
Sweet peas,
clover, other
leguminous
weeds
Soil is sandy or
alkaline, too
well drained, or
needs nitrogen
Wild lettuce,
lemon balm,
cleavers,
chickweed,
plantain
Indicates a
balanced PH,
soil is well
drained and
fertile.
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As organisms decompose complex materials, or consume other organisms, nutrients are converted from one
form to another, and are made available to plants and to other soil organisms. All plants – grass, trees, shrubs,
agricultural crops – depend on the food web for their nutrition.
- Collect in a plastic bag a sample of soil and leaf litter from a depth of four to six inches underground. The
sample should be moist, since there isn’t much life in dry soil and leaves.
-Place a piece of wire mesh (½ inch holes) inside a funnel and rest the funnel inside an empty coffee can. Put
the soil sample on top of the wire mesh.
-Hang a light bulb over the can. Shine the light directly on the soil. The heat from the lamp will drive the soil
critters deeper as they look for moisture. They will land in the bottom of the can.
-Dumping the can onto a large sheet of white paper or a tray will allow you to see what is living in the soil.
Note: Also living in the soil are animals as large as woodchucks. Moles, voles and other mammals are a few of
the soil’s inhabitants. Some of these larger animals, mix the soil and change its physical characteristics. As
these animals burrow and tunnel, they mix the soil, allowing air and water to penetrate beneath the ground’s
surface. Their waste products help to aggregate soil particles, improve soil structure, and conserve nutrients in
a less mobile state.
How does this help you with your soil improvement plan?
Healthy, living soils have a healthy active food web. Soil organisms decompose organic materials in the garden,
including manure and compost. They fix nitrogen from the atmosphere, making it available to plants. Many
organisms enhance the water holding capacity of soil by building organic matter. Soil organisms prey on crop
pests and are food for above-ground animals. If your soil does not have these things, it is an indication of
compaction, low organic matter or other soil problems.
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10. Soil in the Massachusetts School Garden - Massachusetts Agriculture in the Classroom 2012
Insert 5 Macro-invertebrates you might find in healthy soil
Earthworms: Segmented soil critters without legs that move by expanding and
contracting their bodies like an accordion. As earthworms eat, they break down
plant materials into smaller pieces, aerate the soil, and add nutrients in the form
of castings (soil and nutrient-rich wastes that have been digested and released).
Centipedes: Predatory soil critters that move about quickly on many legs.
Their bodies are flattened and each body segment has only one set of legs.
(Centipedes bite)
Millipedes: Long, rounded soil critters that have hard segmented bodies
with many legs. Each body segment has two pairs of legs. As
vegetarians, millipedes eat holes in fallen leaves and other things, thus
enabling smaller decomposers to continue the decay process.
Springtails: These soil critters literally spring to life when approached. A pointed
projection folded inward at the tip of their abdomens can be quickly extended,
acting like a spring to propel them into the air. Springtails feed on fungi and other
molds, bacteria and decaying matter.
Mites: These very small soil critters look like minute dots moving about in the
soil. There are thousands of species and they range in color from white to bright
red. Mites are related to spiders and have eight legs and a round body. They eat
fungi, other molds and decaying wood and leaves.
Isopods: These soil critters are covered with flattened plates of armor,
resembling tiny armadillos. They are brown or gray in color. Isopods eat
decaying leaves and wood and are often found in damp leaf litter and rotting
wood. They are commonly called Sowbugs or, if they roll into balls when
disturbed, Pillbugs.
Test 7: Identify any Buried Utility Lines in your School Yard Soil
Before digging in settings near buildings, especially if making deep in-ground beds, you should make sure you
will not hit any underground utility lines. “Dig Safe” is a program funded by utility companies. When you call
Dig Safe, they then notify relevant utility companies who will come and flag out the location of any buried
utility lines.
-Stake out the areas you intend to dig
- Call 1-888-DIG SAFE at least three days before digging.
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11. Soil in the Massachusetts School Garden - Massachusetts Agriculture in the Classroom 2012
Techniques for Amending and Building Soil in Your Garden
1. Composting
As composting is such an important technique we have devoted an entire “How-To Guide” to it, and will not
cover it here. While not a cure-all, the addition of compost can help with most soil needs, and if there is a
single thing you you should do for your garden soil, it is to add compost! Compost can enrich the soil with
nutrients, increase moisture retention, improve soil structure and provide a good environment for beneficial soil
organisms. Adding a healthy amount of compost, at least 1” a year to your garden may make all of our other
recommendations unnecessary!
2. Cover Cropping
Planting grasses and other plants you don’t intend to use directly for food in your garden has valuable benefits.
These benefits include their functions as a “cover crop” - protecting the soil from erosion and compaction, and
to out-compete weeds in a dormant bed. They can also function as a “green manure” when these plants are
incorporated into the soil to increase fertility or organic matter content. Finally, these plants can be used as a
“living mulch,” when under-se eded with vegetable crops, keeping out weeds, keeping the soil cool and
preventing erosion. Although these plants can serve all of these functions and more, they are most commonly
referred to as cover crops.
A typical time to cover-crop is in the fall, to prepare for the winter, when you have taken your seasonal crops
out of your beds. You can then dig in the crop in the early spring to prepare your soil, a few weeks before you
begin planting your vegetables if your soil is dry enough to work. If it is too wet and you would compact your
soil by working it, consider adding these plants to the compost heap instead.
Insert 6
Three Cover Crop Combinations for the School Garden
Crop When to
Sow
Use
Winter Rye/ Hairy Vetch Fall A good winter cover crop combination. The
vetch, a legume (like a pea or bean) captures
nitrogen for spring vegetable crops.
Red Clover/ Oats Spring A good quick growing combination that can
be tilled in for a fall garden. Red clover has
good phosphorous accumulation.
Buckwheat/ Soybeans Spring The buckwheat is fast growing and
accumulates phosphorus, the soybeans
nitrogen. Good as a part of a crop rotation
and the soy beans may be harvested.
(adapted from : “Green Manures for Home Gardens” in the Rodale Encyclopedia of Organic Gardening
(see sources))
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12. Soil in the Massachusetts School Garden - Massachusetts Agriculture in the Classroom 2012
How to plant a cover crop :
• Choose a cover crop for your garden, taking into consideration its intended use, and time of year. (See
Insert 6 for some options.)
• Remove all crops residues from your beds, level and rake the bed free of lumps.
• Scatter the seed as evenly as possible by hand. (Try to get kids to hold it palm up and to make circular
motions with their hand to scatter it. This helps avoid all the seed landing in a clump in one corner of the
bed!)
• Tamp all over the bed with the back of a hoe to ensure good soil contact. You can cover the area with
loose straw or grass clippings to help prevent the soil from drying out before the plants germinate.
• If no rain is forecast, water in well, and continue to water often during the germination period of your
seeds to prevent the seed bed from drying out.
To turn the bed over to vegetable production:
• Dig in your crop before it goes to seed! Chop up large pieces with a shovel or even shears. mix into the
soil.
3. Crop Rotation
Rotating groups of crops between beds can have some similar benefits to cover cropping for your garden soil.
Planting legumes such as beans and peas can fix nitrogen for following crops. For more information on plant
families and the multiple benefits of crop rotation, see the Selecting Crops for the School Garden how-to guide.
4. Liquid Soil “Teas.”
Compost tea is made by steeping compost in aerated water. Other liquid applications can be made by steeping
green, un-composted plants in water. The resulting teas are used for either a foliar application (sprayed on the
leaves) or applied to the soil.
Compost tea, like compost, contains nutrients, microorganisms, and compounds called humates. Humates help
plants better use nutrients already in the soil among other benefits. Although compost tea has some benefits as a
fertilizer, its major contribution is in adding microorganisms to the soil. These provide protection against
diseases, especially root diseases; improve soil structure with associated benefits of aeration and water
retention; and improve nutrient uptake.
Why go to the trouble of making compost tea rather than just adding compost? First, compost tea makes the
benefits of compost go farther. When sprayed on the leaves, compost tea helps suppress foliar diseases,
increases the amount of nutrients available to the plant, and speeds the breakdown of toxins.
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How to make compost tea:
You will need:
• 1 five gallon bucket
• 1 gallon of mature compost or vermicompost (worm castings)
• 1 aquarium pump
• 1 gang valve (to divide the air supply into several streams)
• 4 gallons of water
• 3 feet + of aquarium hose
• Un-sulfured molasses
1. Attach 3 separate pieces of hose, each 12" long to the gang valve.
2. Place the gang valve onto the bucket and make sure the hoses reach the bottom of the bucket.
3. Fill the bucket with the water, attach the pump to the gang valve and run for about an hour to evaporate any
chlorine in the water. (Chlorine will kill the microorganisms)
4. Stir in the compost and the molasses
5. Continue to run the pump for two to three days, stirring occasionally
6. Tea should smell sweet and earthy at this point. If it smells bad, add to your compost pile instead, but do not
add to your garden. Try again!
7. Strain the tea and use to water or spray your garden. Tea must be used immediately after aeration has stopped
or the microorganisms will die.
See the “Healthy Soil Bed” design at the end of this guide for another example of a method for making tea in
the garden.
4. Other Amendments for Soils:
Although compost is generally a good all-round bet, and enough to help soil in most school garden settings,
other soil amendments and fertilizers may be used in acute situations.
Most commercial fertilizers have 3 numbers on the front label, separated by dashes. For example: 5-10-5. This
is the fertilizer analysis or percentage by weight of 3 major nutrients plants need: nitrogen, phosphorus and
potassium, in that order. These are abbreviated as N-P-K. So a 10 pound bag of fertilizer labeled 5-10-5, would
contain 5% nitrogen, 10% phosphorus and 5% potassium. The remaining 80% could be comprised of other
nutrients and filler.
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Some amendments beyond compost include:
• Aged, composted manure can be used (do not use fresh manure) and its nutrient levels, as with compost can
vary greatly, but is readily available and easily accessed by plants.
• Lime can help make your soil more alkaline and help with magnesium difficulties
• Alfalfa meal or pellets contain around 3 percent nitrogen, and are commonly used as an animal feed. They can
be bought from farm supply shops.
• Fish emulsion (Ranges in content from 4:1:1 to 9:3:0); suitable for foliar feeding of seedlings and the spot
treatment of transplants. It is reputed to prevent stress, stimulate root growth and provide cold protection.
• Greensand (Glauconite) A mined sandstone deposit (typically 0:0:3 or 0:0:6) used as a source of potassium.
Also contains iron, magnesium, silica and other trace minerals. Is a common ingredient in potting mixes.
• Rock Phosphate can be used to add Potassium, Calcium and trace minerals. Typically 0:3:0.
• Soybean meal (8:0.7:2) Useful to augment N and P.
• Commercial Fertilizer such as a 5-10-10 combination.
To improve soil texture and drainage amendments include:
• Leaf mold: This is great for increasing moisture retention in soils. To make leaf mold, simply create a compost
pile made up only of leaves. Cutting them up can speed the process. However expect it to take longer than
compost, at least 6 months. This is a worth-while task if you have sandy soil.
• Peat moss to increase moisture retention
• “Turf face” to improve drainage.
• Compost! compost! compost!
5. Mulching
Mulching is another technique that we have given its own How-To Guide due to its highly valuable and wide
ranging benefit in the garden. Mulching your soil prevents moisture loss in soil and can break down into extra
organic matter. Using compost, leaves or leaf mold, straw, and other materials is a vital step in maintaining
healthy soil. Sheet mulching can be used to build soil up and increase top soil. For more on this topic, see our
Building the Garden Beds how-to guide. Also see this guide for information on double digging, a technique
which improves soil texture and drainage.
6. Working With Contaminated Soils
When engaging in urban agriculture, which is accurate for many school gardens, lead and other contaminants
are a real risk. If your soil test shows lead or other heavy metals, you will need to determine the level, and the
next steps will be the main priority in your garden planning. Because of the possibility of small children eating
or tasting soil, soils with lead levels exceeding 100 ppm should not be used for gardening at your school. In this
situation, you would need to create a barrier between a container or raised bed and the ground, such as with pool
14
15. Soil in the Massachusetts School Garden - Massachusetts Agriculture in the Classroom 2012
or septic fabric or a closed box. Excavating the soil and replacing it is also an option, but costly. There has been
success absorbing lead with plants such as sunflowers and mustard greens, but this takes many years. These
plants are then removed from the site and put into the trash. The Food Project in Boston conducted a study on
this technique and determined that mustard greens could remove 300 ppm over the course of 7-10 years. This
could be an interesting task for children to do in a new garden site for children in the future!
Even with levels under 100ppm, steps should be taken to minimize absorption of lead by plants:
Insert 7
Gardening Practices to Reduce Lead Exposure
(Adapted from UMass Extension Center for Agriculture: Soil Lead: Testing, Interpretation, & Recommendations -
see sources)
1. Locate your school garden away from the drip line of your school if it is an old building,
and also away from heavily travelled roads.
2. Give planting preferences to fruiting crops (tomatoes, squashes, peas, beans, sunflowers,
corn).
3. Add organic matter such as high quality compost to your soil to make up at least one-third
of the soil in your beds. This will significantly reduce lead availability. Organic
compounds bind lead and make it less available to plants.
4. Maintain soil PH levels above 6.5. Lead is relatively unavailable to plants when the soil
PH is above this level. If needed, add lime. Lead is also less available when soil
phosphorus levels are high.
5. Wash hands immediately after gardening and prior to eating. (Good practices in general
for the school garden)
6. Discard outer leaves before eating leafy vegetables. Peel root crops. Wash all produce
thoroughly.
7. Protect garden from airborne particulates using a fence or hedge (fine dust has the highest
lead concentration).
8. Keep dust in the garden to a minimum by maintaining a well-mulched, vegetated, and/or
moist soil surface.
15
16. Soil in the Massachusetts School Garden - Massachusetts Agriculture in the Classroom 2012
healthy soil bed scale 1/2”= 1’
!ese plants will be able to be harvested in the spring near the end of the school year to make a natural liquid
fertilizer. Pair with rainwater collected from your garden shed.
establishment
Plant dwarf comfrey one foot in from the edges of the bed. Plant yarrow 3 feet from outside edge and seed
white clover in the spaces in between. Water in during establishment.
fertilizer recipe
For comfrey, if you are starting with a newly established plant, cut the leaves once in June to prevent "owering
and allow the plant to grow and die back so as to build up reserves. Once the plant is well established, cut it
before "owering in May when about 2# high. Don’t cut later than September to allow the plant to recover
food reserves before winter dormancy. As comfrey plants become strong they will be ready for cutting every
4 or 5 weeks giving 3 to 5 cuts per season. For yarrow, cut part of the plant in early June with comfrey leave
the rest to grow back. Leave white clover in the ground as a low growing nitrogen $xing groundcover.
Place the plant’s leaves into a large container, preferably one with a tap or hole at the bottom, and a tight lid at
the top to exclude water and "ies and keep any smell inside. Some recommend simply covering the bottom of
the bucket/container with leaves while others advise to $ll the bucket full. A black
liquid smelling of ammonia will soon collect in the bottom. !e solution needs to be diluted 15 - 20 times
with water before application in the garden (For comfrey, this results in an N.P.K. = 0.5 : 0.4 : 3.8. - high in K).
(adapted from Make your own liquid garden fertilizers by Mark Krawczyk)
Maintenance
Water and weed as needed. Plants can be le! or cut back for the winter.
16
Insert 8:
Bed design by Lisa DiPiano of Mobile Design Lab, Northampton MA
17. Soil in the Massachusetts School Garden - Massachusetts Agriculture in the Classroom 2012
Sources
USDA Natural Resources Cons. Service
State Office 451 West Street
Amherst, MA 01002
(413) 253-4350
Web Site: www.nrcs.usda.gov
http://soils.usda.gov/sqi/assessment/assessment.html
http://soils.usda.gov/sqi/concepts/soil_biology/soil_food_web.html
Local USDA NRCS Offices:
Barnstable: (508) 771-6476
Greenfield: (413) 772-0384
Holden: (508) 829-4477
Northampton: (413) 586-1000
West Wareham: (508) 295_5151
Westford: (978) 692-1904
* Free list of educational materials.
National Assn. of Conservation Districts
P. O. Box 855
League City, Texas 77574-0855
(800) 825_5547 Fax (713) 332 5259
Web Site: www.nacd.net
* Free list of educational materials.
Soil & Water Cons. Society of America
7515 Northwest Ankeny Road
Ankeny, IA 50021-9764
(800) THE Soil Fax: (515) 289-1227
Web Site: www.swcs.org
* Free list of educational materials.
17
18. Soil in the Massachusetts School Garden - Massachusetts Agriculture in the Classroom 2012
Other Soil Web Sites
Soil Society of America
www.soils.org
National Wildlife Federation
www.nwf.org
USDA Agricultural Research Service
Kids Science Projects
www.ars.usda.gov/is/kids/fair/story.htm
NASA Goddard Space Flight Center
Soil Activities for Kids
http://ltpwww.gsfc.nasa.gov/globe/index.htm
Project Soil
http://projectsoil.org/project_soil
Soils and Conservation Website
with Soil Zoo
www.waite.adelaide.edu.au/school/Soil/index.html
The University of Massachusetts Soil and Plant Tissue Testing Laboratory. (413) 545-2311 or e-mail to
soiltesting@hotmail.com. http://umass.edu/plsoils/soiltest/
The Illinois Agriculture in the Classroom Ag Mag Issue 22
The National Wildlife Federation’s Educators Guide and information supplied by Al Averill, Greenfield MA Office,
USDA NRCS.
On Compost Tea:
“Fine Gardening” website: http://www.finegardening.com/how-to/articles/brewing-compost-tea.aspx
Pensylvania Department of Environmental Protection website: http://www.dep.state.pa.us/dep/deputate/airwaste/wm/
recycle/Tea/tea1.htm
Worcester Roots “Lead Safe Yard Manual” : http://www.worcesterroots.org/2011/08/15/lead-safe-yard-manual/
Soil Lead: Testing, Interpretation, & Recommendations: Prepared by Tracy Allen, Lab Supervisor, UMass Soil and Plant
Tissue Testing Laboratory; John Spargo, Assistant Extension Professor of Soil and Nutrient Management and Director,
UMass Soil and Plant Tissue Testing Laboratory; and Baoshan Xing, Professor of Soil Chemistry. January 2012.
18
19. Resources for Building the Garden Beds
Soil in the Massachusetts School Garden - Massachusetts Agriculture in the Classroom 2012
The Food Project website, Boston MA
http://thefoodproject.org/soil-testing-and-remediation
Rodale's All-New Encyclopedia of Organic Gardening: The Indispensable Resource for Every Gardener. Rodale Books:
1993, Fern Marshall Bradley (Editor), Barbara W. Ellis (Editor)
Images
http://bugs.adrianthysse.com/wp-content/uploads/2012/01/centipede.jpg
http://www.biologycorner.com/worksheets/earthworm_observation_living_key.html
http://www.onewaypestcontrol.com/spring-tails
http://www.pestmall.com/blog/pest-info/other-pests/millipedes
http://insects.tamu.edu/fieldguide/aimg1.html
http://nesoil.com/properties/color/sld010.htm
P. O. Box 345 Seekonk, MA 02771
www.aginclassroom.org
Please Visit the Massachusetts Agriculture in the Classroom Website
to tell us how you used this Soils Resource for the School Garden.
Thanks!
Local and National Organizations
Massachusetts Department of Agricultural Resources
www.mass.gov/agr
Massachusetts Flower Growers Association
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Massachusetts Nursery Landscape Association
www.mnla.com
National Gardening Association
www.garden.org
www.kidsgardening.org
UMass Extension
www.umassextension.org/index.php/information/
gardening
UMass SoilTesting
www.umass.edu/soiltest/
USDA Food and Nutrition Program
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USDA Plant Hardiness Zone MAP
www.usna.usda.gov/Hardzone/ushzmap.html
US Botanic Garden - Planning Planting
www.schoolgardenwizard.org
Other Curriculum Resources Websites
American Community Garden Association
www.communitygarden.org/docs/how-to_manual.pdf
American Horticulture Society
www.ahs.org
California Agriculture Foundation
Gardens Curriculum
www.cfaitc.org/gardensforlearning
Gro Edibles
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Junior Master Gardener Program
http://jmgkids.us
My Healthy School
www.myhealthyschool.com/gardens/starting.php
New York City’s School Garden Program
http://growtolearn.org
Project Life Lab Science School Gardens
www.lifelab.org
School Garden Weekly
http://schoolgardenweekly.com
Soil Water Conservation Society
www.swcs.org
School Garden Transformations
www.schoolgrounds.ca/projects.html
USDA Natural Resource Conservation Service
www.nrcs.usda.gov
http://soils.usda.gov/
Vegetable Garden Basics - Rutgers
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Raised Bed Container image - http://images.taunton.
com/enewsletters/vg/kg08-raised-beds-09.jpg
Information for this How-To-Guide for Getting Started in the School Garden
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Thank you to the Massachusetts Department of Agricultural
Resources for a Specialty Crops Grant that supported development of
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