Healthy soil makes healthy roots. Healthy roots make healthy plants. Healthy plants resist drought, disease, and pests. 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.