How to grow Carob

Where to plant

Carob does best in a Mediterranean climate: cool but not cold winters, warm springs and hot, dry summers. Mature trees take frosts down to about 20°F, but young trees are damaged by frost, and frost at flowering reduces the crop. Ripe pods must stay dry; rain or heavy dew on brown, sugary pods makes them ferment.

It suits Southern California, the hot, dry Central Valley, the Desert Southwest and the dry leeward sides of the Hawaiian islands. In Florida and the Gulf South, humidity and summer rain mean it rarely sets pods, and winter freezes stop it cropping in Texas and anywhere colder. It grows in almost any soil, from rocky hillsides to heavy loam, as long as it drains well; it does not tolerate acid or waterlogged ground.

Choosing a variety

Most carob trees are either male or female, and some are hermaphrodite. Only female and hermaphrodite trees bear pods, and a female tree needs a male nearby. Seedlings take years to show their sex and quality, so for fruit, buy a grafted or budded tree of a named, pod bearing variety, ideally a hermaphrodite that crops on its own. California trials have tested several Mediterranean varieties, such as Tantillo from Sicily, a hermaphrodite that bears heavily.

How to plant

1. Plant a young container tree; large carob trees do not transplant well because of their deep taproot.
2. Plant in spring after frost, or in October in the desert and Southern California, avoiding the hottest months.
3. Dig a hole as deep as the container and wider, and set the tree at the same depth it grew.
4. Water deeply after planting and through the first few dry seasons while roots establish.
5. Cover young trees on frost nights for their first few winters.

Watering and feeding

Established carob trees are extremely drought tolerant and thrive on little rain. If you want a good pod crop, give a deep watering in very dry seasons. Avoid frequent shallow watering and soggy soil.

Most growers consider fertilizer unnecessary for carob, which, like other legumes, is adapted to poor soils.

Pruning and care through the year

• Growth is slow in the first year, then steady.
• Carob can be grown as an informal or clipped hedge as well as a tree. UC notes trees need plenty of room, as the roots can break sidewalks, so plant well away from paving.
• Avoid overwatering and keep lawn sprinklers off the trunk; carob dislikes constantly wet soil.

Harvesting

Pods ripen in late summer and fall, turning dark brown and leathery. Harvest them before fall and winter rain; shake or knock them down onto a tarp. Dry the pods in the sun for a day or two until crisp, then store them dry.

A budded tree in California may give about 5 pounds of pods at 6 years old and about 100 pounds (45 kg) at 12 years, and a tree can stay productive for 80 to 100 years.

Using it

Chew the dried pods as a sweet snack, discarding the hard seeds, or grind seeded pods into carob flour to use in drinks, baking and confectionery as a chocolate substitute. Boiled, crushed pods make a thick, honey-like syrup. The seeds yield locust bean gum, a common food thickener.

Propagation and saving seed

Fresh seeds germinate quickly. Dried, hard seeds need to be nicked and soaked until they swell before sowing. Seedlings are slow and of unknown sex, so fruiting trees are usually budded or grafted with a known variety.