You can grow almost any plant in a container in California. Containers are helpful when you have a small yard and they allow you to move plants around. For example, if you grow a palm tree or a citrus in a large container, you can move it indoors or to a frost-free environment when cold weather arrives. Most vegetables do well in containers, as do herbs, flowers, dwarf fruit trees, bulbs and other ornamentals.
Lemons, oranges and limes do well in containers. If you rent your home, growing a citrus tree in a large container is a good option to planting one in the ground because someday you might need to move. Dwarf citrus trees need a slightly acidic potting soil, full sun and good drainage, so make certain your container has at least one drainage hole. If your winter temperature often drops below freezing, you can move your potted citrus tree indoors before the first fall frost. Grapefruit trees grow larger than lemons, oranges, limes and other citrus, so they might not be your best choice for a container garden.
Palm trees add a tropical touch to patios, decks and lanais. But many palms are frost tender, so if you plant these types in the ground you risk losing it when Jack Frost visits. Smaller palm varieties are especially well suited to growing in containers. Choose from an Areca palm, a windmill palm, a dwarf Phoenix date palm and other species. Choose a potting soil that has some sand or vermiculite added to give it good drainage and water retention capability. The coconut palm is not well suited to life in a container.
Tomatoes, peppers, eggplant, green beans, lettuce, spinach, cabbage, broccoli and many other vegetables can grow well in containers. Make sure you use a good potting soil that contains plenty of organic matter---you can ensure this by adding compost to equal about ¼ the volume of your container. Half wine or whisky barrels work well for vegetables. Drill 10 or 12 half-inch holes in the bottom to make sure your little garden has good drainage. Don't crowd your plants and give them a balanced fertilizer three times during their summer growing season. Zucchini and other squash that form traveling vines are not appropriate for containers.
From rosemary to basil to more exotic herbs such as rue or St. John's wort, herbs do very well in containers. Attractive ceramic pots make suitable homes for herb plants because most maintain a compact growth habit. Herbs serve well in window boxes, on shelves and ledges and even attached to a fence. In general, herbs don't need rich soil, so any type of potting soil will suffice. Give them plenty of sun and don't forget to water them---the smaller the pot, the faster it will dry out. If you keep you herbs close to your kitchen door, it will be easy to pop out and snip some basil or parsley for the dishes you prepare.
You can add color to your deck or patio with potted flowering plants. From hanging fuchsias to potted geraniums, color brightens up a small area that might not have many other plants. You can grow annuals like marigolds, petunias, pansies and snapdragons in decorative pots and you can also choose from many perennial flowering plants, including those that are native to your area. Consider penstemon, clarkia, lupine, California poppy, ceanothus (wild lilac), Matilija poppy and many others. Flowering summer bulbs also thrive in pots. Gladiolas, tulips, daffodils, iris of all types and others will be out of the reach of gophers and moles when you grow them in containers.