CIRCULAR 347 Revised January 1950 # The Water-Culture Method for Growing Plants without Soil D. R. HOAGLAND and D. I. ARNON Revised by D. I. ARNON This circular discusses the general principles underlying the use of all methods for growing plants without soil. Nutriculture is a term for various methods of growing plants in artificial media, including water culture, aggregate culture, and the "adsorbed" nutrient technique. Most claims for the advantages of nutriculture are unfounded. It is not a new method for growing plants. Anyone using it must have knowledge of plant physiology. Its commercial application is justifiable under limited conditions and only under expert supervision. Nutriculture is rarely superior to soil culture: yields are not strikingly different under comparable conditions. Plants cannot be spaced closer than in rich soil. Plant growth habits are not changed by nutriculture. Water requirements are no less in nutriculture. Nutritional quality of the product is the same. Nutrient deficiencies, insect attacks, and diseases present similar problems. Climatic requirements are the same. Favorable air temperatures are just as necessary as in soil. If you still wish to experiment with nutriculture methods, you will find directions beginning on page 23. The California Agricultural Experiment Station has conducted investigations of plant nutrition using the water-culture technique for over three decades. The objective was to gain a better understanding of factors governing plant growth. Many workers participated in these investigations. Dr. W. F. Gericke proposed that the water-culture method might be adapted to commercial use. In the 1930s, this development was widely publicized. The possibility of growing plants in a medium other than soil intrigued many, leading to extravagant claims. Amateur gardeners sought to make this method a new hobby. Thousands of inquiries came to the University of California for detailed information. Because of doubts about claims for the use of the water-culture method, an independent appraisal was desired. Professors D. R. Hoagland and D. I. Arnon conducted additional investigations and prepared a manuscript for a popular circular on the general subject of growing plants in nutrient solutions. In 1938, neither the California Agricultural Experiment Station nor the authors made general recommendations for commercial crop production. The purpose was to provide technical information for those wishing to experiment with the water-culture method. A cautious and balanced consideration of factors determining success in growing crops was recommended. The purpose of this revised publication remains the same. Experience over the past decade shows that exaggerated claims of early enthusiasts are not supported. Nutriculture is not a new method. The earliest recorded experiment with water cultures was in search of a "principle of vegetation." The real development of the water-culture technique occurred over three-quarters of a century ago. It came as a logical result of modern concepts of plant nutritionCIRCULAR 347 Revised January 1950 # The Water-Culture Method for Growing Plants without Soil D. R. HOAGLAND and D. I. ARNON Revised by D. I. ARNON This circular discusses the general principles underlying the use of all methods for growing plants without soil. Nutriculture is a term for various methods of growing plants in artificial media, including water culture, aggregate culture, and the "adsorbed" nutrient technique. Most claims for the advantages of nutriculture are unfounded. It is not a new method for growing plants. Anyone using it must have knowledge of plant physiology. Its commercial application is justifiable under limited conditions and only under expert supervision. Nutriculture is rarely superior to soil culture: yields are not strikingly different under comparable conditions. Plants cannot be spaced closer than in rich soil. Plant growth habits are not changed by nutriculture. Water requirements are no less in nutriculture. Nutritional quality of the product is the same. Nutrient deficiencies, insect attacks, and diseases present similar problems. Climatic requirements are the same. Favorable air temperatures are just as necessary as in soil. If you still wish to experiment with nutriculture methods, you will find directions beginning on page 23. The California Agricultural Experiment Station has conducted investigations of plant nutrition using the water-culture technique for over three decades. The objective was to gain a better understanding of factors governing plant growth. Many workers participated in these investigations. Dr. W. F. Gericke proposed that the water-culture method might be adapted to commercial use. In the 1930s, this development was widely publicized. The possibility of growing plants in a medium other than soil intrigued many, leading to extravagant claims. Amateur gardeners sought to make this method a new hobby. Thousands of inquiries came to the University of California for detailed information. Because of doubts about claims for the use of the water-culture method, an independent appraisal was desired. Professors D. R. Hoagland and D. I. Arnon conducted additional investigations and prepared a manuscript for a popular circular on the general subject of growing plants in nutrient solutions. In 1938, neither the California Agricultural Experiment Station nor the authors made general recommendations for commercial crop production. The purpose was to provide technical information for those wishing to experiment with the water-culture method. A cautious and balanced consideration of factors determining success in growing crops was recommended. The purpose of this revised publication remains the same. Experience over the past decade shows that exaggerated claims of early enthusiasts are not supported. Nutriculture is not a new method. The earliest recorded experiment with water cultures was in search of a "principle of vegetation." The real development of the water-culture technique occurred over three-quarters of a century ago. It came as a logical result of modern concepts of plant nutrition