Soil is the key.
Invest in your soil bank.

Earthworms make healthy soil.

Constantly tunneling down with bits of organic matter, earthworms create a naturally aerated soil.  These tunnels carry water throughout the soil, where it can be stored and used by roots, while providing good drainage to prevent rot.

After eating the organic matter, they expel castings, which are extremely high in time release nitrogen, phosphorous, and potassium, as well as minerals and micronutrients.

Aerated soil rich in nutrients and full of life is said to have good tilth.  Chemical farming destroys tilth and worms which provide time released fertilizers eliminating the need for chemical fertilizers.

Healthy soil makes healthy roots.

Roots like aerated soil full of nutrients and water.  Roots are better able to absorb simple, time-released nutrients provided in organic form than they are synthetic chemical fertilizers.

Synthetic fertilizers only provide large molecules of a few basic nutrients, usually derived from petroleum, and actually kill earthworms.  Soil that has been chemically treated has poor tilth.

Healthy roots make healthy plants.

Plants that cannot absorb the proper, balanced amounts of nutrients grow weak, unable to provide the necessary ingredients for proper stem and leaf development.

Without a healthy root system, many plants will be easily lost to erosion, since there are no roots in the area to hold the soil in place.  Soil with poor tilth erodes quickly.

Healthy plants resist drought, disease, and pests.

Try it yourself.  Intentionally plant two seeds of anything in two different areas. Treat one organically in good soil, and the other badly (not necessarily with chemicals) in poor soil.  It's an easily verifiable experiment.

The Organic Conclusion

Earthworms make plants resist drought, disease, and pests.  If your plants are covered with pests, you need better soil.  Mort never stops driving this point home.  If you don't have earthworms, you don't have healthy soil with good tilth.  Chemical fertilizers, herbicides, fungicides, and pesticides kill earthworms and microorganisms. Remember, healthy plants produce more and healthier food.  In short, get worms!