Container Gardening Complete

Job:06-700309 Title: CPS - Container Gardening Complete

700309 - ContainerGardens_001-272_FINAL.indd 136 6/5/17 3:02 PM
Job:06-700309 Title: CPS - Container Gardening Complete
Job:06-700309 Title: CPS - Container Gardening Complete

700309 - ContainerGardens_001-272_FINAL.indd 137 6/5/17 3:02 PM

136 chapter 3

You may think all this doesn’t matter for

container gardens, since the root system is

contained in a small area, but if you use a 50/50

blend of compost and potting soil to fill your

containers, quite the opposite is true. The compost

in your containers is alive with beneficial soil

organisms. Plus, compost contains myriad macro-

and micronutrients essential for plant growth.

Science has shown us that encouraging healthy,

biologically active soil is the best way to promote

optimum plant growth, even when plants are

growing in containers.

Nevertheless, there are times when our

container-grown plants need more nutrition,

such as when the nutrients contained in the

compost are depleted or unavailable. For those

times, there are a number of easy-to-use natural

fertilizers that do an excellent job of feeding the

soil. These fertilizers are derived from assorted

combinations of naturally-sourced materials,

and they can readily be added to containers

throughout the growing season. An added

benefit of using these natural fertilizers is that

many of them contain trace nutrients, vitamins,

amino acids, and plant hormones that aren’t

usually noted on the label and are rarely found

in chemical fertilizers. These compounds act as

natural growth enhancers and play a vital role in

the health and vigor of plants.

Reading the Label

When shopping for fertilizers, spend some time

reading the labels. Natural fertilizers have four

main ingredient sources.

1. Plant materials. These are fertilizer
   ingredients derived from plants. A few
   examples include corn gluten meal, alfalfa
   meal, kelp meal, and cottonseed meal.
   2. Manure materials. You may also see
   pelletized poultry manure, dehydrated cow
   manure, cricket manure, bat guano, and
   worm castings or worm “tea” on the label of a
   natural fertilizer.
   3. Animal byproducts. Fertilizer components
   found in this category are often derived from
   the byproducts of our food industry. They
   include things like fish emulsion, bone meal,
   feather meal, blood meal, and crab meal.

Dehydrated cow and poultry manure can be found

in bags at your local garden center, but it’s also

a common ingredient in many natural granular

fertilizer blends.

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Caring for Your Containers 137

4. Mined minerals. Natural fertilizers for
   plants may also include mined minerals,
   such as greensand, rock phosphate, crushed
   limestone, and sulfate of potash.

Using fertilizers containing a combination of

these ingredients is a terrific way to feed your soil

when nutrients become depleted and adding more

compost isn’t an option.

Before choosing any type of fertilizer for your

container garden, however, it’s important for you

to understand the numbers you see on the label.

In addition to listing their ingredients, natural

fertilizers also state their N-P-K ratio somewhere

on the bag. This ratio exhibits the percentage

by weight of three macro-nutrients—nitrogen,

phosphorous, and potassium. For example, a

bag of 10-5-10 holds 10% N, 5% P, and 10% K.

The remaining 75% of the bag’s weight is filler

products. For natural-based fertilizers, the

numbers in the N-P-K ratio are often smaller (2-

3-2 or 1-1-6, for example). This is due to the fact

that the label percentages are based on levels of

immediately available nutrients, and many of the

nutrients in natural fertilizers are not available

immediately upon application; it takes some time

for the soil microbes to process these nutrients

and release them for plant use. Although this

may seem like a disadvantage, natural fertilizers

release their nutrients gradually, serving as a

slow-release fertilizer.

It’s also important to understand how plants

use these different macronutrients.

Nitrogen is a component of the chlorophyll

molecule, and it promotes optimum shoot and

leaf growth. Adding a fertilizer high in nitrogen

(such as 6-2-1 or 10-5-5) to a fruiting or flowering

plant, such a tomato or a petunia, will result in

excessive green growth, often at the expense of

flower and fruit production. But adding it to a

green, leafy vegetable plant, such as spinach or

lettuce, makes much more sense.

Phosphorus, on the other hand, is used for

cell division and to generate new plant tissue. It

promotes good root growth and is used in fruit

and flower production. Phosphorous is particularly

Commercially available granular fertilizer blends are a

great way to add nutrition to your container garden.

Carefully read the labels of any fertilizers you use in

your container garden. Pay special attention to both

the N-P-K ratio of the product and the ingredient list

to determine if it’s the right fertilizer for your needs.

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