Thermometer, Soil, Brass Cone

Quick Answer: The Thermometer, Soil, Brass Cone is a soil thermometer whose sensing end is fitted with a pointed brass cone. A brass cone soil thermometer is pushed into prepared ground so the cone conducts soil heat to the bulb while the scale stays readable above the surface.

What the Brass Cone Does

Brass is a good conductor of heat, so a cone of it around the bulb gathers heat from a larger area of surrounding soil and brings the bulb to soil temperature faster than bare glass would. Its pointed shape also parts the soil during insertion and takes the wear that would otherwise fall on the tip. That combination suits repeated readings in the same bed or moving from plot to plot.

Even with a cone, forcing the thermometer into dry clay or stony ground risks bending it or cracking the glass. Make a pilot hole slightly narrower than the cone with a metal rod, insert the thermometer to the required depth, press the soil back around it for good contact, and wait several minutes before reading. Read the scale with your eye level with the top of the thread.

Compared with the general soil thermometer, this model’s defining feature is the metal tip. The filling, stem length and range are not given in the title; choose a length that reaches the depth you study. For compost heaps and seed trays, a shorter model or a digital multi stem thermometer may be more practical.

Applications

• Seasonal soil temperature records in agronomy and horticulture practicals
• Timing the sowing of heat-sensitive crops in trial plots
• Comparing soil under mulch, bare soil and turf in biology investigations
• Following hot-bed and nursery-bed temperatures while raising seedlings

Specifications

Care & Handling

• Use a pilot rod in firm ground; never hammer the thermometer in.
• Wipe soil from the cone and stem after each use, and dry them before storing to limit tarnish.
• Pull straight out, since bending during removal strains the joint between cone and stem.
• Store it in a case in the lab store, not in a field shed where it may be knocked.

Why Choose LabEquip

Agricultural universities, research farms and school gardens buy brass cone soil thermometers for readings repeated many times through a season. LabEquip lists this model in General Lab Products; send the depth you need to reach via the contact page.

Frequently Asked Questions

Why brass for the cone?

Brass conducts heat well, so it brings the bulb to the soil’s temperature quickly, and it is hard enough to take the wear of repeated insertion without blunting.

Does the cone make readings faster than a plain soil thermometer?

Generally yes, because it increases the contact area with the soil around the bulb. Still wait several minutes after insertion before taking the reading.

How do I get good contact in loose soil?

Insert the thermometer and firm the soil around it with your fingers so there are no air gaps. Air pockets insulate the tip and make readings lag.

Will the brass tarnish?

It will darken over time in damp soil. Tarnish has little effect on the reading; wiping the cone clean and dry after use slows it.

Can it be left in the ground permanently?

It can for a season if it is protected from tools and livestock, but glass parts stay vulnerable. For long-term installations, stations often use permanently mounted thermometers or electronic sensors.

Is it suitable for compost heaps?

Yes for shallow readings, if its range covers the heat of an active heap. Very hot heaps can exceed the scale, so look at the upper limit first.

Last Updated: September 2026