|Potassium (K) promotes disease resistance, water intake and strong root growth. Deficiencies are difficult to detect but are indicated by leaf edges and tips that yellow then brown, and weak stems.
If you are an organic gardener, these numbers can be frustrating. Manure
and other organic materials often don't come with N-P-K ratings, especially
if they are purchased in bulk quantities.
Organic gardeners and Horticulturists reports of "Values of Organic Fertilizers,"
information about how quickly an organic fertilizer releases available nutrients
and a reference list on organic gardening.
"One of the most difficult things to determine for an organic gardener
is how much organic fertilizer to use, say on 1,000 square feet of garden,"
said Penhallegon. "For a fertilizer with an N-P-K ratio of 12-11-2,
this means 12 percent is nitrogen, 11 percent is phosphorus and 2 percent
is potassium. In simple terms, this means each 100-pound bag of the fertilizer
would contain 12 pounds of nitrogen, 11 pounds phosphorus and 2 pounds nitrogen.
"For example, using 12-11-2 fertilizer, if we knew we wanted to
apply one pound of nitrogen, we would use 1-12th of 100 pounds," he
added. "This equals about eight pounds of this fertilizer applied to
get one pound of nitrogen out there in the soil."
Cover crops generally release their nutrients slowly, over a period of
two to six months, said Penhallegon. Nutrient values for cover crops include:
alfalfa (2.5 -0.5 -2), crimson clover (2-0.2-2), Australian winter peas
(3-0-1), annual rye (1-0-1).
Bloodmeal (12.5-1.5-0.6), bat guano (8-5-1.5) and many of the manures
(variable nutrient contents) release their nutrients over a period of two
to six weeks.
Burned eggshells (0-.5-.3), fish emulsion (5-1-1) and urea (urine) (46-0-0)
are the fastest-acting organic fertilizers, lasting only a couple of weeks.
To boost the nitrogen content of your soils, apply nitrogen rich urea
(42-46 percent N), feathers (15 percent N), blood meal (12.5 percent N),
bat guano (12.3 percent N) or dried blood (12 percent N). Manures are usually
less expensive than other animal by-products.
Organic amendments highest in phosphorus include rock phosphate (20-33
percent P), bone meal (15-27 percent P) and colloidal phosphate (17-25 percent
High in potassium are kelp (4-13 percent K), wood ash (3-7 percent K),
granite meal (3-6 percent K) and greensand (5 percent K).
To make soil less acidic, gardeners want materials rich in calcium, including
clam shells, ground shell marl, oyster shells, wood ashes, dolomite and
gypsum (all are at least 30 percent calcium carbonate or straight calcium).
| Plant Nutrient Needs
Sixteen elements have been determined to be essential to plant growth and
reproduction. An element is considered essential if in the absence of one
or more of these elements, plant growth and reproduction is significantly
|The following elements are considered essential plant nutrients:
carbon(C), hydrogen(H), oxygen(O), nitrogen(N), phosphorus(P),
potassium(K), calcium(Ca), magnesium(Mg), Sulfur(S), iron(Fe),
manganese(Mn), boron(B), molybdenum(Mo), copper(Cu), zinc(Zn) and
chlorine(Cl). C, H, O, N, P, K, Ca, Mg and S are needed in large amounts
and are referred to as the macronutrients. Fe, Mn, B, Mo, Cu, Zn and Cl
are needed in small amounts compared to the macronutrients and are
referred to as the minor nutrients. They are called minor nutrients
because they are needed in smaller amounts, this in no way diminishes
|C, H and O are mostly derived from air and water, therefore, we have very
little control over the amount of these elements that plants get. The
remaining thirteen nutrients are taken in by the plant from the soil. We
have more control over these elements through the use of fertilizers.
|N, P and K are elements that are needed in amounts that are usually more
than what the soil can provide. When you see the three numbers on the
side of the fertilizer bag, they are referring to the amount of N, P and
K that the ferilizer contains. Most fertilizer applications consist of a
fertilizer that contains one or more of these three nutrients.
|In most cases, the remaining elements are in sufficient quantities within
the soil that applying these element is not necessary. In fact,
overapplying any nutrient, especially minor nutrients, can be toxic to
the plant. Usually, if there is a deficiency in these nutrients, it is
due to an improper soil pH. A soil
test should be taken to determine the
need to apply minor elements or if a pH correction is needed. If the pH
is right and there is still a deficiency, then you will need to add a
minor nutrient fertilizer.
|The most accurate method of determining crop nutrient needs, is through
tissue analysis . The tissue analysis will tell you what the plant is taking up and it, along with a soil
test , can help you determine what nutrients need to be applied to the crop.
|Organic Fertilizers -
Organic fertilizers come from materials that were at one time living or are byproducts of living things.
Old leaves, peanut hulls, bone meal and animal manures are just a few examples of organic fertilizer sources.
Like the inorganic sources, there are numerous sources of organic fertilizer materials.
The goal of this document is to provide you with a few tips on how to use them properly.
There are advantages and disadvantages to using organic fertilizers.
One advantage of organic materials is that they provide beneficial organic matter
that can improve the soils water and nutrient holding capacity.
This organic matter also creates an environment that encourages beneficial soil organisms such as earthworms.
Another advantage is that organic materials take longer to breakdown and release nutrients.
This creates a slow-release situation that provides nutrients over a
longer period of time and can also help in reducing the loss of nutrients to leaching.
A third advantage to organic materials is that you can sometimes find free or inexpensive sources,
if you take the time to search for them.
Many livestock producers and industries that produce organic wastes are required to properly
dispose of their byproducts and are more than happy for you to take some of this
material off of their hands.
One of the disadvantages is that, depending on the source, organic materials are
more difficult to apply than inorganic fertilizers. Organic fertilizers are
usually lower in nutrient content, therefore requiring more material
to be applied to acquire the same amount of nutrient from an inorganic source.
Most organic materials can only be applied by hand unless you have access to some kind
of specialized, mechanical applicator. Secondly, the slow-release property of the nutrients,
which can be a benefit, can also be a detriment.
If not applied properly and in a timely manner, the nutrients can be tied up in the organic matter
and not be available to the plant, therefore, it is
advisable to apply these materials well in advance of the need for the nutrients so that
there will be enough time for the material to break down. Finally, the nutrient contents of organic
fertilizer materials can be highly variable and makes it difficult to determine the proper amount
|Because of the last disadvantage, the best recommendation is that you have your
organic fertilizer sources tested
for its nutrient content. This will tell you how much of the essential nutrients are available to the plant and
how much material to apply. In North Carolina, NCDA will
test your materials for $ 4.00 per sample. If you use organic materials in large
quantities the cost of analysis is well worth it. This will allow you to reap
the fullest benefit of your fertilizer by applying it in the proper amounts. Keep in mind,
however, that you may not be able to apply all of
the nutrients in the proper amounts. The nutrient ratios don't come out in nice even
numbers like 5-10-5 or 10-10-10, so you may have to supplement organic materials with some
inorganic fertilizers to get the proper amounts of all nutrients.
Is better that you use organic fertilizer materials when possible.
The addition of organic matter to your soil, especially if it is sandy,
can lead to remarkable benefits.
Also, you are making use of material that would otherwise be discarded.
Just be sure that you use them wisely; have your soil and fertilizer sources tested
for nutrient content so that you can apply them properly.
|What is Organic?
Organic refers to a method of growing and processing foods.
Organic growing methods are "Earth Friendly."
Weeds and pests are controlled using environmentally sound practices which sustain the health of our planet,
and ultimately, our own health.
Organic farmers do not use chemicals (pesticides, fungicides or fertilizers)
in an environmentally harmful manner.
They utilize a blend of old and new technologies and scientific research to
balance the Earth's natural ecosystem.
Organic farmers work with nature to build and replenish the nutrients in the soil
through crop rotations, composting, and cultivation.
Every purchase you make is really a vote for the way that product was grown and processed.
Why not vote in favor of protecting the health of our own environment?
|Why Buy Organic?
|For your health!:
Organic growing reduces toxicity in soil, air, water, and in our bodies.
|2. It increases organic availability and competition:
Buying organic increases the demand and therefore the market for organic products. Building the market increases availability of and interest in organics and sustainability.
|3. For the health of the planet.
Buy organic to contribute positively to health by reducing the continued poisoning of our planet.
|4. They often taste better, you get the healthy taste of real vegetables.
|Fundamentals of Organic Gardening & Farming
|No pesticides and insecticides - synthetic pesticides pollute the environment, kill beneficial organisms and don't control pests effectively on a long term basis.
|Conserve / recycle resources by composting vegetable scraps and using animal manure for fertilizer. Increase the organic matter in the soil with compost and 100% organic fertilizers. Let the fertile soil feed the plants.
|Use organic fertilizers - synthetic fertilizers feed the plants in a forced, unbalanced way. Have your soil tested for nutrients and Ph level by a lab that gives organic recommendations, to learn the total and available levels of organic matter and minerals. Use rock powders to increase trace minerals: best materials are from volcanic activity such as granite, lava sand and zeolite. Greensand, colloidal phosphate and glacial rock powder are also effective.
Guidelines: Use 100% organic fertilizer to turf and planting beds in early spring at 20 lbs/1000 sq. ft. Repeat every 60 to 90 days during the growing season if greater response is needed (Three applications per year is normal.) Apply rock powders annually at about 40-80 lbs/1,000 sq. ft. Add fish meal or kelp meal at 10-20 lbs/1,000 sq. ft. to annuals and perennials in the spring and every 60-90 days if needed during the growing season. Add a small handful of soft rock phosphate to each hole when planting bulbs or small transplants.
|Mulch to conserve moisture and keep down unwanted vegetation. Mulch preserves moisture, eliminates weeds and keeps the soil surface cooler, which benefits earthworms, micro-organisms and plant roots.
Application: Cover bare soil around plants with natural mulch such as shredded tree trimmings, shredded hardwood bark and leaves, pine needles, etc. For shrubs, trees and ground covers, use at least 1" of compost and 3" of shredded native tree trimmings or shredded hardwood bark. Mulch vegetable gardens with 8" of partially completed compost or alfalfa hay.
|Encourage life and biodiversity with companion planting, re-introduce beneficial insects, and protect benefical insects that exist, such as ladybugs, earthworms, green lacewings, and trichogramma wasps.
|Water in the early morning hours, and adjust schedule seasonally to allow for deep, infrequent waterings in order to maintain an even moisture level and encourage deeper roots.
Guidelines: Monitor using a water gauge and including natural rainfall, about 1" of water per week in the summer is a good starting point. For foliar feeding, use a siphon attachment to apply a light application of seaweed or compost tea when possible.
|Weeding - hand-pull large weeds, weekly shallow cultivation of soil to expose sprouting weed roots to the air, mulching of all bare soil, and work on soil health improvement for overall weed control. Apply corn gluten meal in the Spring and Fall to control annual weeds such as grass burrs.