The Disadvantages of Growing Plants in Soil

Nutrients

• Your garden's soil has an unpredictable and unknown amount of nutrients. To know how much fertilizer to add for each plant, you must take soil samples to your county extension office for testing regularly. Also, when the soil lacks sufficient organic material such as compost or peat, it is unable to retain water. Plants take up nutrients from the soil through the roots with water. Without sufficient water retention, plants cannot take up whatever nutrients are available.

Pests, Diseases and Weeds

• The soil is also a place for harboring pests, diseases and weeds. Weed seeds blow into your garden on the wind and quickly root in the soil. If the seeds are dropped in fall, they can still lie dormant through winter to invade your garden in spring. Many pests such as grubs, weevils and nematodes live in the soil and damage plant roots. Other pests lay eggs or overwinter in the soil, emerging to damage foliage and fruit of nearby plants. Diseases such as root rot and bacterial wilts are caused by pathogen in the soil

Climate

• Severe thunderstorms, early and late frosts and unseasonably hot or cold weather can damage or kill exposed plants growing in your garden's soil. Simply covering these plants may not be enough to protect them from the weather. A more mobile alternative should be found.

Alternatives

• Soilless gardening has existed since ancient times. Aztec Indians impressed the Spanish conquistadors with floating gardens, and Marco Polo brought back stories of floating gardens in China. Today, the soilless floating garden method is called hydroponics. Plants are floated on a raft while nutrient-enriched water passes by the roots. Another soilless growing method is growing in an aggregate culture like gravel. As water that is rich in fertilizers passes through the gravel providing moisture for the plants, nutrients get stuck in the gravel for plants to use. Aggregate culture works well for plants that are sensitive to over watering.