Farmer Potometer Apparatus

Quick answer: A Farmer potometer is used to measure the rate of water uptake by a cut plant shoot, using a simple single-tube bubble design that gives an indirect indication of the plant’s transpiration rate.

Compared with multi-limb potometer designs, the Farmer potometer uses a more direct, single capillary tube arrangement, which makes it straightforward to set up and read in a routine classroom biology practical. An air bubble is introduced into the horizontal capillary tube, and as the shoot draws up water the bubble moves along the tube; timing this movement over a fixed distance gives the rate of water uptake.

Because the shoot is fitted into the apparatus underwater, the system fills with water rather than air, which is essential for getting an accurate and repeatable reading. This makes the Farmer potometer a practical, easy-to-use option for comparing transpiration rate under different experimental conditions.

Technical Specifications

Applications

• Measuring water uptake rate of a leafy shoot as a proxy for transpiration
• Comparing transpiration rate under different light, wind or humidity conditions
• Routine classroom biology demonstrations of plant water relations
• General coursework investigations into factors affecting transpiration

Care & Handling

• Set up the apparatus underwater when fitting the shoot to avoid introducing air into the system
• Check all joints and seals for airtightness before starting readings
• Handle the graduated capillary tube carefully as it is a fine, delicate glass section
• Rinse and dry the apparatus after use and before storing

Why Choose LabEquip

LabEquip supplies biology demonstration apparatus alongside our wider lab glassware range and chemistry lab equipment to schools, colleges and research laboratories across India. For bulk or institutional requirements, contact us and our team will help confirm the right setup for your practical work.

Frequently Asked Questions

What is a Farmer potometer used for?

It is used to measure the rate of water uptake by a cut plant shoot, giving an indirect indication of the plant’s transpiration rate, using a simple single-tube bubble design.

How does the Farmer potometer differ from other potometer designs?

It uses a simpler, more direct single capillary tube arrangement compared to multi-limb designs, making it straightforward to set up for routine classroom use.

How is the reading taken?

An air bubble is introduced into the horizontal capillary tube, and the distance it travels over a measured time period is used to calculate the rate of water uptake.

What can be investigated using this apparatus?

It is commonly used to compare transpiration rate under different conditions such as light, wind, humidity and temperature.

How is the shoot fitted to avoid air entering the system?

The cut shoot is fitted into the apparatus underwater so that the system fills with water rather than air, ensuring an accurate uptake reading.

Does LabEquip supply Farmer potometers for bulk or institutional orders?

Yes. LabEquip supplies Farmer potometer apparatus to schools, colleges and laboratories across India, including bulk and institutional orders. Contact us for a quotation.

Last Updated: September 2026