The New World Crops of Summer.

Summer favorites differ from spring and fall crops in more ways than their temperature range. They actually come from different parts of the world, with different kinds of soil and growing patterns. If you understand those differences, it will help you to grow them with more success and less effort.

Think of the vegetables of spring and fall—lettuce, peas, fava beans, cabbage, broccoli, kale, radishes, spinach--even wheat, barley, and rye grains. They all come from Europe, which has a lot of coastline and very temperate weather. Livestock like cattle, sheep and pigs were integral to farming. Permanent fields were plowed with heavy doses of animal manure. In the North, summers are cool. Along the Mediterranean, the main growing seasons were spring, fall, and winter, because those were the only times when rain fell. So cool-season crops were dominant in both northern and southern Europe.

In contrast, most of our hot-weather vegetables--beans, corn, tomatoes, peppers, zucchini, winter squash, okra, sunflowers, and watermelon, as well as grains such as sorghum, amaranth, and quinoa all come from North America, South America, or Africa. The hoe, digging stick, and fire were the primary tools used to prepare the ground. The fields were carved out of jungle or brush, used for a few seasons, and then allowed to return to the wild. The primary source of nutrients was the burned or decomposed forest vegetation from clearing the land.

What does this mean for our backyard gardens? Well, it doesn't mean we should trade in our rototiller for a digging stick. It does mean that:

• Summer vegetables don't need the fine tilth (soil texture) that, say, cabbage needs. If you are going to do a hurried job of soil prep, or try no-till gardening, crops like tomatoes and squash are the best candidates for success. They don't need either deep soil preparation or fine texture. They will themselves help prepare the soil for a winter crop that is more picky.
• It is not uncommon to see squash or tomatoes growing out of a compost pile. They don't mind compost that is less finished—not raw and stinky, but still a bit chunky.
• These crops love mulch. They are used to growing out of forest duff, and appreciate the way mulch keeps the top layer of soil moist and biologically active. They also appreciate a light but continuous stream of nutrients as the mulch decomposes.
• These crops prefer cool fungal-dominant compost to traditional hot bacterial-dominant compost. That means that slow compost piles with large amounts of wood chips, straw, leaves, or other carbon will work very well. They need a good dose of potassium and calcium--which they would have gotten from burning the brush before planting.
• Because they do not come from a tradition of intensive cultivation, they need a bit more space, both for root room and for air circulation. A single row of well-spaced tomatoes will often out-produce a thickly-planted bed for that reason.

Peppers are an exception—they come from riverside thickets and do best growing in a crowd on light, fine-textured soil. (They love potting mix.) The top canopy should get full sun, but not the sides of the plants, where too much sun would scald the fruits. I like to plant basil or other herbs around the edge of a pepper bed to protect the peppers from sunscald.