Petrus Langenhoven

Horticulture and Hydroponic Crop Specialist
Department of Horticulture and Landscape Architecture
Petrus Langenhoven's website

24 articles by this author

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Census data showed that in 2014 Indiana (12 acres), Illinois (11 acres) and Kentucky (13 acres) dedicated a very small portion of their food crop acreage to production under protection. According to the USDA National Agriculture Statistical Service 2014 Horticulture Specialties Census, of all the states surrounding Indiana, Ohio and Michigan have grown and sold the most food crops under protection, 24 and 25 acres, respectively. The use of high tunnels for vegetable production seems to be a novelty in the Midwest. But it can be a very important tool for every vegetable grower as it can be used to modify the growing environment for crop earliness, to protect the growing crop against environmental stress, to reduce disease and insect pressure and to extend the growing season. Covering the soil with a high tunnel prevents natural rainfall from washing or leaching nutrients and soluble salts from the soil, can lead[Read More…]


Lettuce is grown in channels using the Nutrient Film Technique

Travelling through Indiana last summer, I realized that many growers plant their crops in soil inside their high tunnels or greenhouses. Soilless production offers different benefits and challenges. This is the first article in a series focusing on soilless crop production in high tunnels and greenhouses. Today we are discussing Hydroponics. What is Hydroponics?  The word hydroponics technically means ‘working water’, derived from the Latin words “hydro” meaning water and “ponos” meaning labor. Hydroponics is a method to grow plants using a mineral nutrient solution, in water and without soil. Two types of hydroponics are commonly found: a) solution culture, and b) medium culture. Solution culture types include continuous flow solution culture (Nutrient Film Technique) and Aeroponics. Medium culture types include ebb and flow sub-irrigation, run to waste, deep water culture and passive sub-irrigation systems. History.  The first research published on the production of spearmint in water was conducted by[Read More…]


In December 2015 I presented a talk at the Certified Crop Advisors Conference in Indianapolis titled ‘Specialty Crops of Indiana’. The information gathered for the talk was so interesting that I thought I would share it with all the Vegetable Crops Hotline readers as well. Data Sources.  Information used to compile this article has been derived from the USDA National Agriculture Statistical Service 2012 Census of Agriculture, the 2014 Crop Values Summary, the 2014 Horticulture Specialties Census, and reports from the Economic Research Service. National Statistics.  In 2012, the production of vegetables in California contributed 26% to the total national acreage, followed by Idaho and Washington each at 8%, Florida and Wisconsin tied at 6%, Minnesota at 5%, and Michigan at 4%. Nationally it was estimated that 2.5 million acres of vegetables, potatoes and melons were harvested for sale, totaling $11.8 billion. In 2014, the value of production increased to[Read More…]


​In March 2015 the Department of Horticulture and Landscape Architecture appointed Dr. Petrus Langenhoven as Horticulture and Hydroponics Crop Specialist. During the past 18 years Dr. Petrus Langenhoven has dedicated his career to the development of the horticulture sector in Sub-Saharan Africa. His career started off at the Agricultural Research Council in Stellenbosch, South Africa. He completed his M.S in Agronomy at Stellenbosch University while working at the Agricultural Research Council. He completed his PhD in Agronomy specializing in vegetable production in high tunnels at Stellenbosch University, South Africa in 2004. He advanced his career at a non-governmental organization, Agribusiness in Sustainable Natural African Plant Products (ASNAPP). As operations director and senior agronomist he led ASNAPP’s greenhouse crop production and specialty fresh market vegetable and herb crop research and technology transfer programs. He specialized in the analysis and development of horticulture supply chains. He has extensive experience in applied on-farm[Read More…]