San José, Costa Rica, since 1956

Triple goodness: Corn, beans and squash

From the print edition

As the hot, arid, wind-blown days of the dry season come to an end, farmers and gardeners around the country are preparing for spring planting. This is the time of transition to the rainy season, and with the greening of the landscape and budding foliage it’s easy to feel spring in the air.  Now’s the ideal time to try planting a milpa with the “three sisters.” 

Ed Bernhardt

Ed Bernhardt

Indigenous tribes from all over this continent developed an essential garden design called “la milpa” for growing three major staple crops – corn, beans and squash. They referred to this triumverate as the three sisters. They discovered that the three grew well together and complimented each other.

Today, gardeners refer to them as companion plants or a guild, as they say in permaculture. The corn plant provides a support for the beans to climb, while the beans provide nitrogen to the soil for the plants to utilize. The squash spreads along the ground, blocking the sunlight to retain moisture in the soil and control weeds. Nutritionally these foods complement each other too. Corn lacks the amino acids lysine and tryptophan, which the human body needs to make proteins and niacin. But beans contain both, which means that together they provide a more balanced diet.

Squash provides high levels of vitamin A to prevent infections and the seeds are also rich in minerals and oils. To start your own milpa, you’ll need at least 10 square meters of garden to ensure the corn plants can pollinate well.  Then dig shovel-sized holes about one meter apart, and add a shovel full of rich compost in each one. Next, plant three corn seeds in each spot.

This method seems to produce healthy, vigorous corn plants. As the plants grow, cultivate the soil around the base of each trio of corn plants to later give them support during the heavy rains. When the corn is knee-high, it’s time to plant one or two pole bean seeds around each corn hill, so they will climb up the growing corn. Squash seeds can also be planted at the same time around the perimeter of the milpa. In this way, as the three sisters grow and mature, you’ll be able to harvest fresh corn on the cob, green beans and young squash at the same time. 

Root crops are also ideal for planting now. Yucca is a favorite crop of the Ticos that is also easy to plant. All that’s needed are 30-centimeter sections of the stems. These stem cuttings are inserted halfway into the ground about 50 centimeters apart. By the time the dry season rolls around again, you’ll find large yucca tubers under each plant.

For the kitchen garden, try planting a collection of lettuce, cabbage, mustard, onions, peppers and tomatoes in flats with prepared potting soil. The flats can be located on the sunny side of the house under the overhang of the roof, preferably on a table to give them protection from heavy rains.

When the seedlings are about 5 cm tall, transplant them to small pots or cups filled with aged compost. Let them grow in the cups for about two weeks, so their roots recover from the shock of transplanting, and the foliage continues to flourish. When the plants are hardy, they can be transplanted easily to the garden beds without losses due to shock of transplanting or bug predation.

All in all, you will find working in nature here in the tropics a very rewarding experience. For more information on tropical home gardening, check our monthly newsletter:

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