Study Guide
In this topic, we will be learning about the importance of soil in supporting plant growth and how
to use fertilizers to promote plant growth. After reading the articles and watching the video to
this topic you should be able to answer the following questions:
1. Define the following terms:
● Topsoil
● Soil texture
● Soil structure
● Soil pores
● Soil pH
● Acid and alkaline soil
● Nutrient deficiency
● Organic matter
● Composting
2. What is the difference between macronutrients and micronutrients? Know if the following
nutrients are macronutrients or micronutrients: nitrogen (N), phosphorus (P), potassium (K), iron
(Fe), and zinc (Zn).
● Macronutrients: Macronutrients are those elements that are needed in relatively large
amounts.
○ Nitrogen produces a deep green color in foliage and promotes overall plant
growth.
■ It usually needs to be applied every year because rain or irrigation will
leach much of the nitrogen not used by plants.
○ Phosphate is essential for vigorous early season growth of seedlings. It moves
very slowly in the soil and best results are obtained if phosphate is banded 2”
below the see or transplant at planting.
○ Potassium:
● Micronutrients: Micronutrients are those elements that plants need in small amounts
(sometimes trace amounts),
○ Iron
○ Zinc
● Both macro- and micronutrients are naturally obtained by the roots from the soil
3. How is the term soil defined and how does the definition depend on the context of the person
using the term? In what ways does soil support plant growth? What are the five components
which make up soil? Why can soil be described as “living”?
● Soil is the weathered surface portion of our planet's crust.
● Through various weathering processes such as wind, sunlight, ice, snow, and rain, large
parent rock material of various origins is broken down over very long periods of time into
ever increasingly smaller and smaller mineral rock particles until the particles are two
millimeters or less in diameter, sometimes microscopic.
● This collection of tiny rock particles at the Earth's surface is what we call soil.
● Soil is the real medium upon which all terrestrial life including ours exists.
4. What percentage of soil is made up of water and air? Where is water and air located in soil?
Why is it important not to overwater your plants?
5. Why is organic matter an important component of soil? What is the difference between sand,
silt and clay? Why is a loam soil often considered ideal for growing plants?
●Cultural practices, such as amending the soil with organic matter, will open up the soil by
improving soil aeration and drainage.
○ A well aerated soil will promote root health by suppressing populations of root
damaging soil bacteria and fungi.
●Soils can be aggregated into three texture classes called sand, silt or clay based on the
dominant particle sizes.
○ Sandy soils have the largest particles, and clay soils have the smallest particles.
●If a garden soil is a mixture of different amounts of sand, silt, and clay sized particles. It
is referred to as Loam
○ Loam soils are generally best for plant root growth and development.
6. How can you determine the texture of your soil? Why is it important to know the texture of the
soil in which you are growing plants? Does a sandy or clay soil need to be irrigated more
frequently for optimum plant growth?
●"field test".
○ To do the field, test take a small amount of clean, moistened soil and compress it
between your thumb and middle or index finger.
○ Then rub it back and forth. Does the soil sample you're rubbing between your
finger and thumb feel gritty, slimy, silky smooth, or sticky?
○ If it feels gritty, then your soil has a sand texture. If it feels silky smooth, then your
soil has a silt texture. Or if it's sticky, then your soil has a clay texture.
● The texture of a garden soil affects how water and air moves through it, how easily the
soil wets, how long it takes to dry out after being watered, and how often your garden
soil will need to be irrigated.
○ The sandier a soil is, then the faster water drains through it and the quicker it
dries out.
■ Sandy soils will need to be irrigated more frequently than silt or clay
soils which drain water and dry out more slowly.
7. What are symptoms in plants of nitrogen and iron deficiencies? Why are plants often nitrogen
and iron deficient in the southwest? How would you prevent or treat nitrogen or iron
deficiencies?
● Nitrogen: General yellowing of older leaves (bottom of plant). The rest of the plant is
often a light green
● Iron deficiency: Yellowing occurs between veins of young leaves
8. Are the soils in the Phoenix area generally acid or alkaline? How can you change the pH of a
soil? Should lime typically be added to soil in our area?
● Our soils are generally moderately alkaline with pH values of 7.5 to 8.5.
○ These alkaline soils affect plant growth and development by limiting the
availability to roots of several key mineral nutrients.
9. What is the difference between an organic and inorganic fertilizer? A simple and complete
fertilizer?
● Typically synthetic inorganic fertilizers are more concentrated compared to natural or
organic fertilizers, which are generally less concentrated with lower numbers.
10. Know the difference between the following types of fertilizers and how they would be used: a
slow or controlled release fertilizer, a liquid fertilizer, granular fertilizer. What do the numbers on
a fertilizer bag stand for? Why is it important to follow the directions on the fertilizer container
concerning rate when applying fertilizer?
●All fertilizers, even organic fertilizers, when dissolved in the soils aqueous fraction for
root uptake are a form of salt and as such interact with other chemical elements in the
soil.
○Liquid synthetic fertilizers or granular fertilizers that readily dissolve in water
are more quickly available for plant root uptake, and are present in the soil at
high concentrations for relatively short periods of time.
○ In contrast, dry fertilizer formulations, especially natural and organic types,
break down and dissolve very slowly in water and are available to plants in
lower concentrations over longer periods of time.
○ Some specialty synthetic fertilizers are designed for a slow release of their
nutrients into the soil over many months.
■ These fertilizer types mimic natural or organic fertilizers in the release
rate and are called controlled-release or slow-release fertilizers.
11. Why are plants in a greenhouse generally not grown in soil? What are the components used
to in soilless mixes/potting soil?
12. Know the definition of:
● peat moss
○ Some of the fertilizer products and soil amendments that can be used to
decrease your garden soils pH by increasing the hydrogen ion concentration of
your garden's soil include acid forming fertilizers such as elemental sulfur any
fertilizer product containing ammonia such as ammonia sulfate or urea, or
organic soil amendments such as peat moss.
● perlite – grey-white porous product used in potting mixes made from heating naturally
occurring silica (volcanic) rock mined from lava flows
● vermiculite – brown porous product used in potting mixes made from heating micaceous
rocks
In closing, thought you might enjoy the following ancient quote: “To be a successful gardener
one must first know the nature of the soil.” – Xenophon, 400 B.C.
Video: Soils and Fertilizers Terms Defined
Introduction
● We're going to check out the terms that are associated with this topic called Soils and
Fertilizers.
Terms
1. Topsoil: Topsoil is defined as the layer of soil that has the highest concentration of
organic matter and microorganisms, and is where most of the earth's biological activity
occurs.
● Generally speaking, topsoil is superficial, meaning it resides above other layers
of soil.
● Topsoil can range anywhere from virtually no depth at all here in the desert
Southwest to several feet.
2. Soil texture: Soil texture is the measurement of the proportion of mineral particles of
different sizes that are found in the same sample of soil (sand, silt, clay).
● The qualitative measure of these different sized particles is referred to larger
particles being sand, intermediate particle sizes being silt, and the smallest sized
particles being clay.
3. Soil structure: Soil structure is the way that individual particles of sand, silt, and clay are
arranged into larger distinct aggregates.
● Soil structure is the major factor that determines how fast air and water enter and
move through the soil profile.
4. Soil pores: air spaces in-between particles of soil that allow for the passage and
absorption of fluids through and into the soil profile.
5. Soil pH: The soil pH is a measure of the acidity or alkalinity of a parcel of soil. Soil pH is
measured on a negative logarithmic scale of 1 to 14. 7 is neutral, or the middle value.
6. Acid and Alkaline soil: Soil pH less than 6.5 is acidic. Soil pH greater than 7.5 is alkaline.
Soil pH between 6.5 to 7.5 is neutral
●\ Values that are less than 7 are considered acidic. And, values that are greater
than 7 are considered alkaline.
● In the desert, most of our undisturbed soils are slightly to moderately alkaline and
have pH values that range generally from 7.5 to 8.5.
7. Nutrient deficiency: an inadequate supply in the soil of one or more of these essential
elements for plant growth and development.
● Most plant biologists recognize that exists about 16 essential plant nutrient
elements that are required for plant growth and development.
● These essential elements include compounds such as nitrogen, phosphorus,
potassium, sulfur, iron, zinc, and manganese and magnesium.
8. Organic matter: carbon-based plant or animal remains in the soil that have decayed
beyond recognition.
● Organic matter is important for your successful gardening her in the desert
Southwest. We define
9. Composting: Composting is the aerobic, active, and directed decomposition of organic
matter.
● Because it's aerobic, successful composting requires the presence of oxygen.
○ Because it's active it requires oxygen and water.
● And because it's directed it means we're doing it!
Video: Soils
Introduction
●During the 1930s, a severe multi-year drought gripped the central United States and our
time in our nation's history when soil conservation practices had not yet been embraced
by our nation's agricultural sector.
○ Erosion of our soil resources was rampant and dangerously unsustainable.
○ This period of time is now infamously referred to as the Dust Bowl era.
●It ultimately led then President Franklin Delano Roosevelt to write famously in a 1937
letter to all the state governors that the nation that destroys its soil destroys itself.
●Soil is one of the most foundational natural resources that a nation has
●In this video we'll explore together the essence of soil, its value and necessity for life,
and how we can tend soil in order to successfully garden in the desert Southwest.
What exactly is soil?
●Soil is the weathered surface portion of our planet's crust.
●Through various weathering processes such as wind, sunlight, ice, snow, and rain, large
parent rock material of various origins is broken down over very long periods of time into
ever increasingly smaller and smaller mineral rock particles until the particles are two
millimeters or less in diameter, sometimes microscopic.
●This collection of tiny rock particles at the Earth's surface is what we call soil.
●Soil is the real medium upon which all terrestrial life including ours exists.
Is soil dirt?
●"SOIL IS NOT DIRT!!!"
○ Dirt is what you scrub and wash off with water and Tide Pods when you get it on
yourself under your fingernails or on your clothes.
●Soil on the other hand is a precious resource that is to be tended and cared for and ever
the more so as the demands and stressors that we place upon it increase.
Healthy soil
●A healthy soil is made up of five component parts. They are:
○ 1) weathered mineral particles of various small sizes,
○ 2) macro and micro living organisms (with fungi being in the most prevalent),
○ 3) the decomposing organic matter from dead organisms both large and small,
○ 4) water, and finally
○ 5) air
●When viewed in this light, soil is understood as a substance that is full of life with its own
unique ecology of biological processes and organism interactions.
Soil Layers
●If you've ever looked into a soil pit or on a freshly excavated road site cut out, then
you've likely seen that soil is made up of various layers.
●These layers are called soil horizons.
●The arrangement of these horizons in a soil is known as the soils profile.
○ There are three main soil horizons - the A horizon, the B horizon, and the C
horizon.
■ An organic layer on top of the A horizon is known as the O horizon.
■ And the R horizon refers to the bedrock beneath the C horizon.
●The nature and structure of these horizon layers is very specific to a garden site and is
affected by the prevailing climate.
●Soil horizons are 1) highly variable, 2) shallow, 3)limited to non-existent surface layer of
organic matter.
Soil texture
●A second way to classify soil is by the size of the particles, and is referred to as a soil's
texture.
●Soils can be aggregated into three texture classes called sand, silt or clay based on
the dominant particle sizes.
○ Sandy soils have the largest particles, and clay soils have the smallest particles.
●So how can you quickly determine the texture of your garden soil?
○ One simple low-tech way is to use what is called the "field test".
●To do the field, test take a small amount of clean, moistened soil and compress it
between your thumb and middle or index finger.
○ Then rub it back and forth. Does the soil sample you're rubbing between your
finger and thumb feel gritty, slimy, silky smooth, or sticky?
○ If it feels gritty, then your soil has a sand texture. If it feels silky smooth, then your
soil has a silt texture. Or if it's sticky, then your soil has a clay texture.
●If a garden soil is a mixture of different amounts of sand, silt, and clay sized particles. It
is referred to as Loam
○ Loam soils are generally best for plant root growth and development.
Texture effects
●Now the texture of a garden soil affects how water and air moves through it, how easily
the soil wets, how long it takes to dry out after being watered, and how often your garden
soil will need to be irrigated.
●The sandier a soil is, then the faster water drains through it and the quicker it dries out.
○ Sandy soils will need to be irrigated more frequently than silt or clay soils which
drain water and dry out more slowly.
●The immediate soil environment in which a plant's root system is growing is called the
rhizosphere.
○ The rhizosphere has three important functions.
■ 1) First, a healthy and well-developed root system is physically
supported and anchored in place by the rhizosphere.
■ 2) Second, the rhizosphere functions as a reservoir of water oxygen
and essential mineral nutrients that a plant needs to grow and
reproduce
■ 3) the rhizosphere functions as a substrate for any interactions that
plant roots have with other living organisms, such as bacteria or fungi
●A few of these interactions can be damaging to the plant, such as the invasion of plant
roots by root rotting bacteria or fung.
○ But the reality is that most associations that plant roots have with other
organisms living in the rhizosphere are symbiotic or even beneficial.
○ For example: mycorrhizae fungi- an intimate and often beneficial soil
association between fungi and roots
■ Fungi provide phosphorus to the plant in exchange for carbon
Here's a sustainable tip!!!
● Cultural practices, such as amending the soil with organic matter, will open up the soil
by improving soil aeration and drainage.
○ A well aerated soil will promote root health by suppressing populations of root
damaging soil bacteria and fungi.
Soil PH
●Describes a soil’s chemical condition.
●Mathematically speaking, pH is the negative log of the hydrogen ion concentration
(pH=-log [H+])
●A soil's pH is expressed numerically on a scale of 1 to 14.
○ The more hydrogen ions that are present in the soil, the lower the pH number will
be.
○ A soil pH of 7 is referred to as neutral.
○ Less than 7, then a soil's pH is considered to be increasingly acidic as the pH
number lowers.
○ Greater than 7, then a soils pH is considered as increasingly basic or alkaline as
the number increases.
● Soils around the world that are able to support plant growth generally range in pH
from 4 to 9.
●Our soils are generally moderately alkaline with pH values of 7.5 to 8.5.
○ These alkaline soils effect plant growth and development by limiting the
availability to roots of several key mineral nutrients.
●Now knowing your garden soils pH is an important initial step to developing the very best
management practices to nurture your garden soil health and grow the very best garden
plants.
Outro
●In this video, we've discussed what soil is and what its basic components are we've
reviewed how we can classify soil according to its horizon profile and texture, and how
soil supports plant growth and development.
●We have also discussed what soil pH is, and how the alkaline pH of desert soils affects
the availability of soil mineral nutrients for plant uptake.
●Now a healthy soil is the foundation of successful southwest home gardening.
○ Knowing what type of soil supports your home garden is critical to knowing how
to best manage your Southwest garden plants.
Video: Fertilizers
Introduction
●
● Our amazing and beautiful world, the old terra firma, is made up of 90 naturally occurring
elements ranging from hydrogen to uranium.
● Many of those elements such as carbon, nitrogen, potassium, and iron are vitally
important to life on Earth.
● Like the nutritional status of our own bodies, the nutritional status of plants is affected
by the intake of essential elements in the right concentrations and at the right times.
● Now in this video, we'll learn about the essential elements that plants require that are
obtained as minerals from the soil, what happens to plant performance when they are in
short supply, and how we can manage essential mineral nutrient shortages through the
proper use of fertilizers.
Why do plants need minerals?
● Unlike animals, plants are autotrophic.
● Whereas you and I eat food to derive the energy we need to live and grow, plants don't.
●They make their own food internally from carbon dioxide in the air, sunlight, water, and
thirteen other naturally occurring, essential mineral nutrients that their roots absorb
directly from the soil.
○ These thirteen essential mineral nutrients are placed into two groups based on
the relative amounts that plants need in order to grow and reproduce.
■ 1) The first group of six mineral nutrients are called macronutrients.
● These macronutrients are nitrogen, phosphorus, potassium,
calcium, magnesium, and sulfur.
●Plants require these macronutrients in relatively higher
amounts. For example, a healthy garden plant typically has
anywhere between 2 to 4 percent of its tissue by weight
comprised of nitrogen.
■ 2) The second group of 7 mineral nutrients are called micronutrients.
● They are iron, zinc,manganese, boron, copper, molybdenum, and
nickel.
● Like macronutrients, these micronutrients are also essential for
plant growth and development, but it's just that plants require
these mineral nutrients in substantially less amounts to
function.
How are plant nutrients replenished?
● One way is by the recycling of dead organisms, primarily plants, into the soil as organic
matter.
○ However, our desert soils are generally very low in organic matter content
because of our relatively dry climate.
● Now because of this, our desert soils are inherently lacking the right amounts of
several of the essential mineral nutrients that many of our landscape garden plants
need.
Short supplies of mineral nutrients and their effects
● Two essential mineral nutrients that are most often in short supply in desert landscape
garden soils are nitrogen and iron.
○ The lack of or availability of adequate amounts of nitrogen or iron in the soil can
lead to inadequate amounts in plant tissues causing plant deficiency symptoms
to occur.
●Plant deficiencies in nitrogen or iron, though the most common nutrient problem in
desert garden plants are displayed by the plants very differently.
Nitrogen deficiency Symptoms
● 1) The first deficiency symptom that generally appears is a slowing of growth or a lack of
plant vigor.
○ This is because nitrogen is an elemental building block of amino acids, proteins
and enzymes that regulate growth processes.
● 2) General yellowing or reddening of predominantly older leaves on the lower parts of
the plant.
○Older leaves show nitrogen deficiency symptoms first because plants are
able to mobilize and move nitrogen throughout the plant to points of greatest
need, which are mostly young and developing plant tissues and not older leaves.
Iron deficiency symptoms
● Iron is central to the formation of the green pigment molecule in plants called
chlorophyll, which is responsible for a leaf's green color.
● 1) When plants lack iron, the first deficiency symptoms seen is a yellowing of new
leaves instead of older leaves like with nitrogen.
○ Younger leaves are affected first because plants are unable to mobilize and
move iron throughout the plant to points of greatest need, which are mostly
young and developing plant tissues.
○ The yellowing of younger leaves caused by an iron deficiency is not a general
yellowing like nitrogen, but rather presents itself as a yellowing of parts of
the leaf in between the leaf veins, which remain green.
■ Has a netted appearance.
● The deficiency symptoms that garden plants show when inadequate levels of zinc and
manganese occur look similar in appearance.
○ Interveinal iron, zinc, or manganese deficiencies are common in garden plants
when desert garden soil is moderate to strongly alkaline pH.
■ This is because alkaline soils strongly bind iron, zinc, or manganese to
soil particles, especially silt or clay, making them unavailable for
absorption and uptake by plant roots.
● Desert soils typically have little organic matter or available nitrogen and that essential
mineral micronutrients such as iron, zinc, and manganese are made unavailable for
plant root uptake when soil PHS are alkaline
Best and most sustainable strategies for managing desert soil
● How to manage the desert soil of your home garden?
○ Depends on the type of home garden that you have
■ Ornamental and desert native gardens do not need regular amendments
or fertilizers
■ In contrast, home vegetable and fruit gardens in desert soils need regular
amendments or fertilizers
Here's a sustainable tip!
● Organic matter that is added as an amendment into vegetable and fruit garden soil is
slowly decomposed by bacteria and fungi.
● Organic matter amendments release of humic acids into the surrounding soil slowly
reducing the harmful effect of soil alkalinity by slowly lowering the pH (or
acidifying the soil)
Fertilizer law
● Essential plant mineral nutrients that we add to the soil are called fertilizers.
● Now the commerce of all fertilizer products is governed by state law.
○ Today, most states have similar laws about fertilizers because of interstate
commerce.
●Arizona state law defines fertilizers as any substance or mixture of substances
intended to be used for promoting or stimulating the growth of plants, increasing the
productiveness of plants, improving the quality of crops, or producing any chemical or
physical change in the soil.
● Fertilizers are classified by origin and chemistry
○ In terms of origin, fertilizers are either derived from natural sources or
manufactured or synthesized.
○ In terms of chemistry, fertilizers are either inorganic or organic.
● Now the issue of what are inorganic and organic fertilizers can be sometimes confusing.
○ Some interpret organic- byproduct of living organisms.
■ Others use a more restrictive definition and classify organic fertilizers as
only those that contain the element carbon.
Local plant nursery fertilizer
● So you're at your local plant nursery or home improvement center to purchase a
fertilizer product for your home garden.
● Here are some tips for you to keep in mind that'll help you purchase the best product for
your garden needs.
○ 1) First, state laws require that any fertilizer products sold commercially must be
accompanied by a product label.
■ The fertilizer product label must be predominantly displayed on the
fertilizer bag or container, and must give information about the fertilizers
chemical content, proper use, handling, and storage, as well as any
health and safety precautions.
Fertilizer product label
● Now when using a fertilizer product, I recommend that you always read the product label
and follow the label instructions.
● 1) One of the first things you'll notice is that on the product label are displayed three
hyphenated numbers that are referred to as a fertilizers analysis of grade.
○ These three numbers give the approximate percentages by weight of total
nitrogen, available phosphorus, and soluble potash or potassium contained
within the product.
○ The higher the numbers are the greater the concentration amounts of nitrogen
phosphorus or potassium that are in the fertilizer bag.
● Other nutrients in a fertilizer product such as calcium magnesium, sulfur, or any micro
nutrients like iron, zinc, or manganese, if present, are listed separately on the product
label.
● Typically synthetic inorganic fertilizers are more concentrated compared to natural
or organic fertilizers, which are generally less concentrated with lower numbers.
Formulation types
● Fertilizers come in many different types of formulations ranging from dry powders and
granules to concentrated liquids.
● The formulation type most importantly relates to the solubility of a fertilizer or its ability to
dissolve in water.
● Since plant roots absorb only mineral nutrients that are suspended as a dissolved salt in
the soil’s water or aqueous fraction, the type of fertilizer formulation and its solubility
affects how quickly or slowly a fertilizer is taken up by plant roots after it's applied
to the soil.
●All fertilizers, even organic fertilizers, when dissolved in the soils aqueous fraction for
root uptake are a form of salt and as such interact with other chemical elements in the
soil.
○Liquid synthetic fertilizers or granular fertilizers that readily dissolve in water
are more quickly available for plant root uptake, and are present in the soil at
high concentrations for relatively short periods of time.
○ In contrast, dry fertilizer formulations, especially natural and organic types,
break down and dissolve very slowly in water and are available to plants in
lower concentrations over longer periods of time.
○ Some specialty synthetic fertilizers are designed for a slow release of their
nutrients into the soil over many months.
■ These fertilizer types mimic natural or organic fertilizers in the release
rate and are called controlled-release or slow-release fertilizers.
Doctor’s choice
● For long term soil health, I prefer to use natural organic or even sometimes controlled-
release, synthetic fertilizers in my landscape garden because of their slow release rate
of mineral nutrients as dissolved salts into the soil.
● Natural and organic fertilizers do a better job in supporting the long-term health of
populations of beneficial soil bacteria and fungi.
Garden soil management tip for you!
● If your garden soil's reservoir of essential mineral nutrients is running low and you need
to apply fertilizer to fill up your soil nutrient reservoir, but you're not sure about how much
fertilizer to apply, then always apply less than you think you should, and never more.
○ You can always add more later if needed.
○ Applying too much fertilizer and the resulting excess salts in your garden soil
might burn tender and succulent plant roots, especially as the soil is allowed to
dry out in between waterings.
The Big Question
● Can the normally alkaline pH of a desert garden soil be lowered from what usually is
around 7.5 to 8.5 to a more reasonable favorable slightly acidic to neutral pH of 6 to 7 in
order to increase the availability of iron zinc and manganese root uptake?
○ The answer is a qualified yes.
● Some of the fertilizer products and soil amendments that can be used to decrease your
garden soils pH by increasing the hydrogen ion concentration of your garden's soil
include acid forming fertilizers such as elemental sulfur any fertilizer product containing
ammonia such as ammonia sulfate or urea, or organic soil amendments such as peat
moss.
○ However, my own personal opinion about the use of strong acidifying fertilizers to
lower the pH of desert garden soils is that it's a little like trying to get the
shampoo out of your hair when you're at Venice Beach in California.
■ For a brief moment it seems like it's rinsing out, but invariably the soap
keeps coming back. And the same will happen to the alkalinity of your
desert garden soil.
Be sustainable
● 1) avoid unnecessary soil disturbances.
● 2) Layer the surfaces of your garden soils with compostable organic mulches.
● 3) Select garden plants that grow well in alkaline soil pH
● 4) finally use organic or natural fertilizers only as needed.
Gypsum to lower soil pH?
● This narrative is bogus! It's absolutely false!
● Gypsum is calcium sulfate. Like other minerals, gypsum slowly dissolves in water into a
stable salt and has no ability to lower pH by increasing the concentration of
hydrogen ions in soil.
● However, gypsum can be used as a soil amendment that when mixed into soil will
improve its structure by increasing aeration and drainage.
○ Thus, gypsum is a valuable amendment for improving the structure of damaged
or compacted soils with poor aeration and drainage.
Fertilizer Use, Handling and Storage
● 1) First I've already emphasized the need to read and follow the directions on the
product label when using any fertilizer product.
○ But label directions are written generally, and often don't specify application
amounts for certain plant types, plant size, or plant age. So as a reminder, if
you're reading the product label and you're still unsure about the right amount of
fertilizer to apply to a plant, then always apply less than you think and wait to
see how the plant responds before applying more.
● 2) Second, when handling any fertilizer product, always wear non-absorbing, water
resistant glove and wear a protective facial mask
○ For example, synthetic inorganic fertilizers such as ammonium sulfate generally
have a higher salt concentration that can irritate or even burn sensitive skin.
○ Organic fertilizer products, especially those derived from animal byproducts such
as manure, bone meal, blood meal or fish emulsion, contain pathogens that can
infect human skin.
● 3) Always store any unused fertilizer products in a dry secure location.
○ I've found that old used plastic five gallon paint buckets when cleaned out and
dry make excellent storage containers for unused fertilizers.
○ Store individual fertilizer products separately in separate containers.
●Never under any circumstance mix different fertilizer products together when
storing them for the next use.
Outro
● Now in this video, we've discussed what are the thirteen essential mineral nutrients in
soil that are needed by plants to survive, and how a soils pH particularly the alkaline pH
of our desert soils affects the availability of soil mineral nutrients for plant uptake.
● We also discussed how we can recognize plant nutrient deficiencies that are common in
desert soils, particularly nitrogen and iron.
● And how natural organic or synthetic fertilizers can be wisely used to augment soil
mineral nutrient status.
● As Jane Shellenberger wrote, our most important job as vegetable gardeners is to feed
and sustain soil life, often called the soil food web, beginning with the microbes. If we do
this, our plants will thrive will grow nutritious healthy food, and our soil conditions will get
better each year. This is what is meant by the old adage, "feed the soil, not the plants".
