The New World Crops of Summer

expanded 5/​2021

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 a lot 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. Every single one comes from Europe, which has a moderate climate like our Pacific Northwest. European crops primarily evolved from maritime and cool-climate plants, under traditional mixed-farming conditions. Livestock like cattle, sheep and pigs were integral to farming. Permanent fields were plowed with heavy doses of animal manure and matured during a temperate summer. In the warm Mediterranean regions with dry summers, they were all grown as winter crops.

In contrast, most of our hot-weather crops--beans, corn, tomatoes, peppers, zucchini, potatoes, squash, watermelon, and okra, sorghum, amaranth, millet, 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 left fallow. Their fallow period was not as pasture, as in Europe, but as forest. The primary sources of nutrients were the ash from burning, and the decomposed forest vegetation from clearing the land. Crops were sown in place rather than transplanted, and cultivated with hand tools, not draft animals. In some places, they were planted, then left while the farmer went hunting or gathering elsewhere, to return for harvest. Many are extremely vigorous, to overtop or clamber over logs and debris. Look at those sunflowers, corn, and amaranth plants at Golden Rule Garden, above. These are plants that use sunlight and heat to power explosive growth.

What does this mean for us? I've realized more and more that these crops are at home in our backyards: They evolved with hot weather, small plots, and hand labor. They are forgiving of neglect. Sounds like my garden! 

• These vegetables don't need the fine tilth (soil texture) that, lettuce or cabbage needs. If you are going to do a hurried job of soil prep, or try no-till gardening, crops like tomatoes, potatoes, 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.
• Traditional farmers with hoes instead of plows were able to do companion planting. (They didn't have to leave long rows for an ox to walk through.) An indigenous North American combination was the Three Sisters: corn sunflowers, or amaranth, plus beans, and squash. An African combination was sorghum or millet, cowpeas, and collards. (Plus sweet potatoes, which work in the South. Elsewhere, try delicata squash.) In all regions, staple crops were interspersed with flowers, minor crops, edible weeds, basketry/dye/fiber plants, and herbs for cooking, healing,  and ceremony. 
• It is not uncommon to see squash or tomatoes growing out of a compost pile. They don't mind compost that's not finished. Not raw and stinky, but still 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 can deal with cool fungal-dominant compost as well as 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 also need a good dose of potassium and calcium--which they would have gotten from burning the brush before planting. If you use a woodstove and have clean ashes, they may be a good addition to the soil. (get a soil test, though.)
• Because they do not come from a tradition of intensive cultivation, they need 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.

Flowers like zinnias, marigolds, cosmos, and sunflowers are also from the Americas and follow the same pattern of hot-weather growth. 

Peppers are New World plants that come from riverside thickets and arroyos. They do best growing close together on light, fine-textured soil; a bed works better for them than rows. I've had great success growing them in a dozen pots pushed close together. (Potting mix is perfect for their small, non-aggressive root systems.) The top canopy should get full sun, but not the sides of the plants--it scalds the fruits. I like to plant basil or other herbs around the edge of a pepper bed to prevent sunscald.​ In some traditions, they were grown either in with other creekside plants like wolfberries, or in the light shade of mesquite trees.

A three Sisters garden with pole beans growing up corn, squash at their feet, and zinnias attracting pollinators. All of these plants are native to the Americas, and have been grown together for millennia. A grouping like this is easy in a home garden, difficult or impossible in large-scale farming.

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