Sometimes, what seems to be an easy question is not so easy! With that in mind, this is the second of a series of two articles discussing how fertilizers work, and then the difference between organic and inorganic fertilizer. Last week in Part 1, we discussed the science behind fertilizers and what the soil really needs to be healthy. (If you missed Part 1, use this link to read it now.)

For bacteria to do all of the work in your soil changing unusable nitrogen into nitrate nitrogen which the plant can use, they need an energy source containing carbon. This is where the organic compost comes in. Compost is partially decomposed plant parts (leaves, fruit, flowers, wood, or roots) and provides the energy source bacteria need to do their nitrogen conversions. Think of the compost as providing energy for the bacteria as a slice of bread would provide you with energy but not provide many vitamins and minerals you also need for good health. In the same way, animal manures have practically no fertilizer value (little or no nitrogen, phosphorous, potassium, iron, etc.) because the animal used most of that during digestion and discarded the undigested cellulose (carbon). Witness a nice dried cow pie or horse bun. The manure is mostly dry grass and a good carbon source which provides the bacteria with the energy they need to do their work.

A second important function of composts and manures is to help "loosen" our heavy clay soils. The organic matter mixes with the clay soil and increases the amount of air spaces, thus improving drainage and air circulation for plant roots. The air spaces are also needed to provide the oxygen the bacteria need to do their work. If there were little or no organic matter (compost) in the soil, there would be no energy source for the bacteria. If there were few or no bacteria there would be few or no nitrogen conversions. If there was no nitrogen converted to nitrates, there would be no plant or animal growth. The other minerals which the plants need are dissolved from the clay soil.

If we use nitrogen as an example of one element necessary for plant growth, how do organic matter and organic fertilizer provide this element? To a gardener, "organic" means that it is or was alive or came from a living thing. When you read the list of ingredients on a box of Dr. Earth or other organic fertilizer, you see products such as blood meal, feather meal, cottonseed meal, fish meal or alfalfa meal. These are all high protein materials and as we outlined last week, nitrogen is the basis for all protein products. Remember, too, that with a few exceptions, plants can use only Nitrate Nitrogen for making their proteins. The plants can not take animal protein as found in feathers or blood and change it directly into plant protein.

When we sprinkle Dr. Earth or other organic fertilizer on the soil, bacteria go to work again; a bit more complicated this time but still requiring bacteria, oxygen and the carbon (energy) source for the bacteria. The protein source--it could even be a dead bird or fish--is consumed by decayed bacteria and broken down into amino acids (and frequently some unpleasant smells!). Another group of bacteria convert the amino acids into ammonia. Then, a third group of bacteria converts the ammonia and oxygen into nitrites. Finally, the fourth group of bacteria converts the nitrites into nitrates and the plants are set to use them for their own needs. This process has a few more steps than using the chemical fertilizers and takes a bit longer to become available for the plants but the fertilizer lasts longer and is less likely to wash away. As you see, the end result is the same: whether it is organic or inorganic, the plants can use only nitrates, the last stage of each cycle.

When Mother Nature is left alone, all of the dead things (organic matter) go into the soil and are totally recycled. Over the years, the soil actually becomes more fertile, develops a better structure and has a great increase in the number of beneficial microbes. When we move on to Mother Nature’s land and upset the fine balance she has established, we have to scramble to restore some sense of order. We attempt to do this with our composts and fertilizers.

A word about mycorrhizae. This is the collective term for more than 2500 different species of fungi associated with the roots of plants. Some live outside the roots and some live inside. They act as if they were part of the root but go a step further by breaking down minerals or organic matter in the soil before helping them get into the roots of the plants. Each different kind of plant seems to have its own set of mycorrhizae and there appear to be greater numbers in poor soil than in a rich soil. Some horticulturists have recommended that to inoculate your soil with the right kind of mycorrhizae, you should take a small shovel full of soil from around the roots of a healthy plant which is the same as the one you are going to plant and place this in the hole with the new plant.

Summarizing, fertilizer alone will not increase or improve the plants in your garden. Your soil must have adequate microbes (bacteria and fungi), oxygen and moisture. The soil must be friendly to the bacteria before they can make use of whatever fertilizer is used. Our heavy clay soils are not friendly to bacteria. The soil can only be made more friendly by incorporating organic matter and by mulching the surface with two to four inches of suitable compost.

The Wegman's Annual Inventory Reduction Sale is just around the corner! Get ready, set and save 30% on all 1 gallon and larger perennials, shrubs, fruit trees, and shade trees. Also save 30% on a large selection of pottery, statuary, garden ornaments, houseplants, planters, trellises, water pond products, giftware, and hanging baskets. Wegman’s Annual Inventory Reduction Sale starts Friday, August 29th at 7 am; and the first 100 customers receive a special savings coupon.

The Sale ends Sunday, September 7th, and is limited to stock on hand and does not apply to any special orders. Additional discounts don’t apply. Delivery is available at current rates. So get ready for Wegman's quality at Wegman's 30% off!

The hydrangeas are spectacular this year! Come in and see the wonderful selection available.

Hydrangeas need a rich, well draining soil for the best growth. The colors of the garden hydrangea can be intensified by adjusting the pH of the soil. ‘Nikko Blue,’ for example, can have its pale blue flower changed to a deep dark blue by acidifying the soil with Aluminum sulfate. The aluminum fraction also plays a role in color production. Aluminum sulfate must be applies to our soils before the flower buds are fully formed. We recommend that it be applied for at least three months in November, December and January. More often would also be fine since it will maintain the lower soil pH.

Our clay soils are naturally alkaline so genetically pink flowering plants will remain pink. Pink and red flowering plants can have their colors intensified by adding oyster shell lime to the soil on the same schedule as the Aluminum sulfate.

For additional information view the article ‘Caring for Hydrangeas’ in our Archives: Edition 709, March 1, 2007.

Snapdragons are a particular favorite of children who like to pinch the tiny individual blossoms and make the "dragon mouth" open and close. Their large, blossom-laden flower heads are faintly fragrant and come in a wide assortment of bright colors. The vertical flower spikes, opening gradually from the bottom to the top, are available in two heights: dwarf varieties grow to about 10 inches while the taller types grow to a height of 18-24 inches.

Snapdragons make excellent cut flowers and excel in beds and at the front of borders. Snapdragons flourish in well-fertilized soil and full sun with average watering. Snapdragons bloom from late summer through fall.

Dr. Earth Fruit & Vegetable Insect Spray
Environmentally Safe:
Controls Aphids, Leafhoppers, Japanese Beetles, Caterpillars, Whiteflies, Mealybugs, Mites, Scale & other insects.

Description:
A superior blend of rosemary oil, cinnamon oil, clove oil, garlic extract, coconut oil, mineral oil, wintergreen oil, safflower oil, mosses and water.

Dr. Earth Rose & Flower Insect Spray

Environmentally Safe:
Controls Aphids, Fungus Gnats, Japanese Beetles, Caterpillars, Whiteflies, Mealybugs, Mites, Scale, Ants & other insects.

Description:
A superior blend of rosemary oil, cinnamon oil, clove oil, garlic extract, coconut oil, mineral oil, wintergreen oil, safflower oil, mosses and water.