We grow garlic.. lots of it. 40+ varieties in 2011. We attend garlic workshops and seminars. The last couple of years we have been warned about an approaching problem … that of nematodes that like to eat and destroy garlic bulbs.

hot mustard

hot mustard seed

So the best advice from the provincial ministry, of garlic growing farmers and researchers and experts is to be proactive. One of the methods was to prepare a bed for garlic the preceeding summer (we plant garlic in the late fall), by planting hot mustard and cutting it down before it goes to seed, at least twice.
Till this in and finish the 2nd tilling a few weeks before planting the garlic. This will hopefully inhibit the activity of any bad nematodes thinking about coming this way.

Marigolds are also recommended in helping to repel/minimize nematode issues so we planted some of those as well, not mixed in with the mustard but next to it.