Do Plants Grow Larger in Water or Soil?

Nutrients

• Plant nutrients can be divided into mineral and non-mineral nutrients of which the non-mineral nutrients are carbon, hydrogen and oxygen. The six mineral macronutrients have the most influence on plant growth, most importantly nitrogen, phosphorous and potassium. These are most responsible for growth whether the plant is being grown hydroponically or in soil.

Hydroponics

• Hydroponics are generally used to grow annual crops such as salad greens, peppers and tomatoes, particularly in cooler climates where the production occurs in greenhouses and extends the growing season. In these plants, maximum height and size can be easily achieved by controlled application of nutrients. Hydroponics is not usually used to grow larger, long-lived perennials such as trees.

Influence of Other Factors on Growth

• Daylight hours and air temperature will influence the growth of plants regardless of the medium in which they are grown. Plants grown in soil are also subject to the temperature of the soil, while hydroponically grown plants are often in greenhouses and sheltered from the extremes of weather.

Conclusion

• Given equal amounts of sunlight and similar temperatures, the amount of nutrients available to the plants, -- particularly nitrogen, phosphorus and potassium -- will determine plant size, not the growing medium.