Most
seasoned gardeners know that the secret to healthy, productive gardens is
really no secret at all. It’s in the dirt, literally. Plants need moisture and
sunlight to grow and, in the right amounts, they will flourish, but only if you
start with good soil.
Like us,
plants need food, in their case it is in the form of nutrients. Good soil
provides these nutrients and also allows plants to take them up.
However,
before knowing if your soil is healthy or not, you need to decide what type of
soil you have. There are three main types, sandy, silty and clay. The particles
that make up the soil are what are used to categorize each type by size. Sandy
soil has the largest particles, clay the smallest and silty fits in the middle.
The
combination of these three is what gives soil its texture. Sandy soil is easy
to cultivate, drains more easily but requires more water since it doesn’t
retain it. Silty soil has good water retention and circulation and is good for
growing crops. Clay soil is easily compacted, is difficult to plant or even
shovel because it clumps. Although it is hard to work with, it is able to hold
roots better and has a more stable environment than the other two.
There is an
easy DIY test to evaluate what type of soil you have. Dig down about six inches
where you want to test. Fill a Mason jar about half full of the soil and then
fill it to the shoulder with water. Set it aside to let the soil soak up the
water.
Next, put
the lid on and shake it for about three minutes. Set the jar down and leave for
one minute. Then, measure the amount of sediment that has collected in the
bottom. This is the amount of sand in the soil. Wait four more minutes and
measure again. The difference between the two numbers in the amount of silt.
After 24 hours, measure again. The difference between the second and third
numbers will be the clay in the soil.
Calculate
the different percentages of sand, silt and clay. The three numbers should
equal 100 percent. Healthy soil is typically 20 percent clay, 40 percent silt
and 40 percent sand. Results of this test will help you determine what to grow
since different plants prefer different soil types. For example, silt and clay are hard to get
wet but stay wet longer. Plants that like “wet feet” are happy here.
For the
optimal garden, you can either choose plants accordingly or amend the soil
type. For sandy soil, add humus, peat moss or aged manure. A warning about
manure, it must be aged at least six months otherwise you run the risk of
introducing new pathogens into your soil.
For silty
soil, add coarse sand (not beach sand), gravel and compost or well-rotted horse
manure with fresh straw. Coarse sand is also known as yellow or builder’s sand
and is not as fine as beach sand nor does it contain salt like beach sand.
To amend
clay soil, add coarse sand, compost or peat moss. This will make it a little
easier to work with and the sand will create pockets of oxygen to help plant
roots breathe.
When you
know what soil type you have, you will next want to determine what the pH level
is which, in turn, determines whether the soil is acidic or alkaline. There is
also a simple test to determine this. Put two tablespoons of soil in a bowl.
Add ½ cup vinegar to it, if it fizzes, it is alkaline. By the same token, put
two tablespoons of soil in a bowl, moisten with distilled water and add ½ cup
baking soda. If it fizzes, the soil is acidic. If it doesn’t react to either
test, the soil has a neutral pH.
Either a
high or low pH may result in plant nutrient deficiency or toxicity. When it is
neutral, microbial activity is greatest and plant roots absorb nutrients best.
Once you
know what you have, you can adjust the pH of the soil. Acidic or sour soil is
adjusted by applying finely ground limestone and alkaline or sweet soil is
treated with ground sulfur. Keep in mind, some plants prefer acidic soil or
alkaline soil so treat your soil based on what you want to grow.
If you do a
professional soil test, such as from the county extension office, the results
will address the three elements of nitrogen, phosphorous and potassium. This is
why fertilizers are blended with different percentages of these three elements,
so they can be tailored for your soil type.
Nitrogen,
characterized by N in a blend, helps plants make leafy growth and gives plants
their good green color. It is part of every protein in the plant so it is
required for every process. Insufficient nitrogen is characterized by general
yellowing of the plant. Ten pounds of blood meal has the same amount of
nitrogen as 20 pounds of manure, minus the organic matter.
Phosphorous,
denoted by a P, is necessary for germination, strong root growth and producing
flowers and fruit. It helps plants absorb minerals, grow strong stems and
withstand disease. Bone meal is a good source.
Potassium,
known as K, regulates the water in plant cells and is necessary for flowering,
fruiting, good root development and for plant stress tolerance. Weak stems and
stunted growth are the results of lack of it. Wood ashes are a good source of
potash, which is where the word potassium is derived from.
Potash is
really various salts that contain potassium in water-soluble form. Before the
industrial era, plant ashes were soaked in water in a pot, thus the name of pot
ash. It was the main source of potassium.
One more
sign of healthy soil is the presence of earthworms. If you dig up one cubic
foot of soil, break it apart and find at least 10 earthworms, then the soil is
healthy. They aerate the soil. If you have fewer, you can add organic matter
like compost, aged manure and leaf mold. This organic matter slowly releases
nutrients to promote microbial activity.
I never
realized how widely different soils vary until I started putting a small garden
out here at Ron’s. His soil is definitely clay whereas I have sandy soil. Mine
is easy to dig and plant in; his not so much. I will never forget the first
time I dug potatoes down at his place. At home, we pull up a vine and shake the
soil off. I was literally shaking the vine to pieces and it wasn’t coming off.
He watched me for a long time before he told me that it was not going to shake
off any time soon!
There is not
a bad nor a good type of soil, only different types. The secret is knowing how
to make whichever kind you have the best it can be for the purpose you have in
store for it.
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