Apply irrigation water so that container substrate is wet throughout the entire volume.

After excess water drains from container, use a large syringe with small tube to remove any extraneous liquid that may be inside the lysimeter. Insert small tube to base of lysimeter traversing hole of larger black tube at top of lysimeter. Initiate and hold vacuum on small tube using a large syringe.

In the image you can see a syringe with a small clear tube that traverses the black tube. The clear syringe tube extends to the bottom of the lysimeter

After evacuating the liquid originally present in lysimeter, create vacuum in lysimeter with hand pump.

An electric pump may also be used to create vacuum in the lysimeter.

Hold vacuum for 5-15 minutes by kinking black tube. Afterwards, remove hand pump from the kinked tube.

A ring should remain in place, securing the tube.

Finally, release the vacuum and remove the liquid sample with a syringe.