germination test - sprouting onions

Is an onion germicidal?

Using a germination test to investigate whether an onion is germicidal

Waterman Onions has been setting up so-called germination tests for its (pool) growers for years. With a germination test, you can quickly investigate whether an onion is susceptible to sprouting. The onion is stimulated to grow ‘further’, so you can soon explore whether an onion is sensitive to germs. It can prevent problems, especially in a difficult growing season.

germination test - sprouting onionsSprouting onions after set up germination test It is a straightforward procedure: You fill a container with a layer of potting soil (approximately 5 cm). If there is still foliage on the onions, cut this off and place the onion 1/3rd part in the potting soil. Place the container in a warmer place (canteen, corridor with underfloor heating or in the windowsill) and water it occasionally so that the ground remains moist.

You will often notice within three weeks whether the onion is susceptible for sprouting. If that is the case, the onions will root in the potting soil, or a green blade will emerge from the onion. Isn’t this the case? Then you can happily store your onions!


You usually place a germination test around November, but from October till the beginning of January are still possible! Good luck!