Q: Having a European background, I...

Q: Having a European background, I love tulips. Being a newcomer to Southern California, I don’t know what the proper time is for planting them here. --O.S., Monrovia A: Most spring-flowering bulbs should be set out as early as possible in the fall but Dutch tulips are the exception. Tulips in mild-winter areas such as ours need to be chilled before planting--to simulate the cold winter they expect, and need to flower properly. My suggestion is that you place tulip bulbs into the 40-degree (Fahrenheit) area of your refrigerator for about six weeks before setting them out. After planting them, keep the soil on the moist side, supplying occasional irrigation if winter rains are absent. Tulips are also planted deeper in the soil than they are in other parts of the country; six inches of soil should cover the bulbs.

Q: I have found nematodes and their damage in my vegetable garden. Isn’t it true that they should be kept out, if possible? --K.E., Westwood A: Yes, they should. There are several ways that you can prevent nematodes from being introduced into a garden or suppress them once they are present. First, never transplant seedlings that are obviously infected or those that have unhealthy-looking roots. If you raise seedlings yourself, grow them from seed in a sterilized soil mix. If you buy yours as started plants, try to use only those--such as tomatoes--that are labeled as nematode-resistant. Some plants are particularly vulnerable to attack. Included among those are beans, tomatoes, peppers, lettuce and carrots. Crop rotation is another effective way to suppress nematodes. One of the best ways to deal with the problem is to relocate your vegetable garden every three years or so to slow down or stop nematode population explosions.