This is one guest you don't want to see leave

Our gardens need many things to thrive. Can you guess what this welcomed guest is?

Its lifespan is two-six years. It is indigenous to Europe and is abundant is North America and Western Asia. There are approximately 2,700 different kinds. Charles Darwin spent 39 years studying them more than 100 years ago. They are cold-blooded animals. They eat their weight each day. They hatch from cocoons smaller than a grain of rice. They have no arms, legs or eyes.

I am sure that you know I am describing an earthworm. You may think it is a simple creature but it can add an important element to your garden. Earthworms need soil to survive. They are found in almost every type of soil, but the healthier the soil, the greater the numbers. A healthy soil permits lots of air and moisture, which is just what the earthworm needs. Earthworms have no lungs - they breathe through their skin. Their entire skin absorbs oxygen and releases carbon dioxide. They also need moisture to assist them in respiration, but too much moisture is not good for them.

There are four types of worms that you may encounter:

• Nightcrawlers are 8 to 10 inches long and are the fisherman's favorite.

• Garden worms are 5 to 7 inches long and found commonly in damp soils.

• Manure worms are 4 to 5 inches long and are found in manure-rich soils.

• Red worms are 3 to 4 inches long and are the most commercially available.

The most common garden earthworm, the nighcrawler, is not native to North America. It was brought over from Europe in potted plants. This is one case where the introduction of a foreign species has been beneficial.

Earthworms may survive being frozen if the freeze is not too rapid. Earthworms do not come to the surface during rain to escape drowning but to find a mate since their mobility is better on wet ground. Earthworms lack eyes but are light sensitive.

You now know many facts about earthworms, but let's discuss why they should be given a home in your garden. They are tireless tillers of our soil, and their castings are the richest and best of all fertilizers. It would be impossible to have too many in our gardens.

Tunneling

Earthworms till the soil by tunneling through it. Tunnels allow air and moisture to pass easily through the soil, creating a healthy environment for plants. Tunnels retain water that the plants can take up and also hold air to help bacteria break down organic matter within the soil.

When worms tunnel deep into the soil, they bring the subsoil closer to the surface, mixing it with topsoil. Slime, a secretion of earthworms, contains nitrogen. Nitrogen is an important nutrient for plants. The sticky slime helps to hold clusters of soil particles together in formations called aggregates.

After digestion, earthworms produce excrement about the size of a pinhead. This excrement is called castings or vericompost and is an excellent soil-conditioning material. It improves the properties of the soil, such as porosity and moisture retention, aids plant growth and helps in the fight against pests and diseases.

Adding them to

your garden

Now you probably want earthworms in your garden, right? It's easy. You can buy earthworms and add them to your garden. Wait until the soil warms before introducing them to your garden. When the weather conditions cause drought or freezing, earthworms can recede deeply into their burrows, which can be 6 feet deep. The mucous from their exterior helps to provide structure to their burrows so that they do not collapse.

In the spring, buy earthworms and introduce them to your garden. First, make sure they will be happy there. Worms live where there are food, moisture, oxygen and a favorable temperature. If they don't have these things, they will either go elsewhere or die.

Add organic matter to the garden soil. This is a great spot for your composted matter. The decaying matter will give your earthworms a splendid buffet. Provide moisture to the soil, enough for deep watering. Turning the soil should be done before introducing the earthworms.

Earthworms are resilient, have a high reproduction rate and can survive without us. With their help and with a little help from us, our gardens will benefit.

For more information, contact The University of Arizona Mohave County Cooperative Extension, 101 E. Beale St., Ste A, Kingman, AZ 86401-5808 or call (928) 753-3788.