No. Where the weather is mild enough you can grow vegetables all year long.
In the early spring you can plant your first round of cool weather crops such as lettuce, spinach, cabbage, kale, broccoli and peas.
In late spring when night time temputures have warmed up it is time to plant warm weather plants like tomatoes, peppers, eggplant, zucchini and squash.
In fall while you are getting ready to harvest your fruit and vegetables, August through October, you can replenish your cool crops again and plant the same plants you did in early spring like lettuce and broccoli. Be sure to check the label to see if it is a fall harvest crop or an overwintering variety. Also this time a year is the best time to plant onions and garlic for large bulbs next summer. You can also plant cover crops overwinter, which I will be discussing very soon in another post.