Soil Water Samplers in Horticultural Nursery Use

Nutrient Extraction from Large Containers

Robert D. Wright, Department of Horticulture

Virginia Tech, Blacksburg, VA 24061

The use of soil water samplers, also called suction cup lysimeters, are suggested for extracting nutrients from large containers (5 gallon and above) since it is a difficult task to elevate relatively heavy containers over a collection vessel. The samplers are installed to the bottom of the container (figure 1) and left in place for periodic sampling of the water in the container.

The sampler consists of a porous ceramic cup attached to the bottom of a sampling tube. One to two hours following irrigation a vacuum pump is used to create a vacuum in the sampler, which draws water from the container through the ceramic cup and into the sampler. Adequate water collects in the sampler in 5 to 10 minutes which can be withdrawn with a syringe for subsequent EC, pH or a complete nutrient analysis. Three or four water samplers should be installed within a block of plants of similar size and nutritional program.

Soil sampler model 1900 L24 with a half bar air-entry value (1900L24-B0.5M2), vacuum pump 2005G2, and 1900K2 extraction kit are recommended. Other vacuum pumps and extraction methods are also acceptable.