Climate guide

Mediterranean-Climate Gardening: Plant When the Rain Comes

6 min read

If you garden in most of California, you already know the year has two colors. The hills go gold in late spring and stay that way all summer. Then the first real rain comes through in the fall, and within a couple of weeks there's a green haze over everything.

Your vegetable garden runs on the same switch. Most planting guides are written for a place where summer is the growing season and winter is the wall. Here, the rain decides when the year begins, and for most of what you'll grow, it begins in the fall.

The short answer: in a Mediterranean climate, the rain sets the year. Cool-season vegetables like peas, fava beans, garlic, onions, broccoli, lettuce and carrots go in with the first soaking fall rain and grow through the mild, wet winter. Summer is dry, so warm-season plants need steady watering, and near the coast, cool nights can hold tomatoes back.

What is a Mediterranean climate?

It's a climate with mild, wet winters and long, dry summers. Nearly all of the year's rain falls in the cool half of the year, and a summer can go by with almost none.

It's named for the lands around the Mediterranean Sea, but it also covers most of California and southwestern Oregon, along with central Chile, the area around Cape Town, and parts of southern and western Australia.

There's a lot of range inside it. The coast stays cool all year, with foggy summers and frost that's rare or absent. Inland valleys bake in summer and get real frost on winter nights. Both share the same rhythm of rain, and that rhythm is what sets the planting calendar.

Why the fall rains start your planting season

In a cold-winter garden, spring is the starting gun, because that's when the ground thaws and the soil warms. In a Mediterranean garden, the ground never really closes for winter. What it's missing for half the year is water.

So the fall rains do the job spring does elsewhere. They soften soil that's been baked hard since spring, they help cool it back down to where cool-season seed will come up, and from then on they do most of the watering for you. A bed planted with the rains can go much of the winter without the hose.

Two things to watch. A light first shower often just wets the dust, so dig down a few inches before you decide the ground's been soaked. And where fall stays hot, especially inland, the soil can still be too warm for lettuce and spinach to come up even after the air has cooled. (Here's how to tell, with a soil thermometer.)

What to plant when the rains come

This is the whole cool-season list:

• Peas and fava beans, which grow slowly through the winter and flower as spring arrives
• Garlic and onions, which spend the winter building roots and leaves, then bulb up as the days lengthen (more on garlic, and why the type of onion matters)
• Broccoli, cabbage, cauliflower, kale and collards
• Lettuce, spinach, chard, arugula and cilantro
• Carrots, beets, radishes and turnips

Transplants get a head start while the soil's still warm. Seed does well once the rain has cooled things down.

Gardening through a wet winter

Winter is the easy season here, for the most part. The rain does the watering, the plants grow steadily in the cool, and most pests slow down.

The exceptions are the wet ones. Heavy clay can stay soggy for days after a storm, and roots sitting in water rot, so mounded rows can help where drainage is slow. Snails and slugs love a mild, damp winter as much as the lettuce does, so a flashlight check after dark following a rain is worth doing. And if the rains stall for a few weeks, which they sometimes do, go back to watering. A dry spell dries out young roots in winter just as it does in summer.

Why summer needs a different plan on the coast and inland

Come late spring the rain stops, and from then until fall, every drop the garden gets comes from you. Warm-season plants go in once the soil has warmed, and they'll need deep, regular watering all season. Drip lines and a good layer of mulch go a long way, since there's no storm coming to make up for a missed day.

Inland, summer is hot, and the hot-climate playbook applies: get warm-season plants in early and let the heat-lovers carry the middle of summer.

On the coast, it's the opposite problem. Foggy summers can stay cool for weeks, and tomatoes set fruit poorly when nights fall below about 55F. The plant grows and flowers, and the fruit comes slowly or not at all. Cherry tomatoes and early varieties do best there, and so does the sunniest, most sheltered spot you have. Peppers and eggplant want even more warmth, so give them your warmest spot of all.

Where Verna fits, and where it doesn't

Verna combines climate data for your exact location with what each plant needs, and puts a window on your calendar for each plant you're growing, so a garden on the coast and one in the valley don't get the same answer. It keeps track of where each plant is in its life through the winter. And its watering nudges look at the plant and the weather where you are, which matters in a place where summer brings no rain at all.

It isn't a rain forecast, though. It won't tell you the first storm is coming next week, or that it only wet the dust. Your trowel still settles that.

The short version

In a Mediterranean climate, the rain sets the calendar. Cool-season vegetables go in with the first soaking fall rain and grow through a mild, wet winter, and the warm-season garden runs on your watering through a dry summer. Inland, plan around summer heat. On the coast, plan around summer cool.

When the hills start to go green, it's time to plant.

See when the window opens in your garden

Verna maps sowing, transplanting, and harvest timing to your exact spot.