When Hernando Cortes and his men entered the Basin of Mexico in 1519, they found the natives employing a unique
agricultural system. This method of farming, which still persists today, consists of land reclamation through the
construction of chinampas in marshy areas and shallow lakes. As the farmers or chinamperos dig out canals in the
lakebed, they pile the mud which they are scooping out atop sedges and reeds. These constructed mounds, which are
surrounded by water on at least three sides, are chinampas and serve as the garden plots in which the people grow their
crops. Homes are also constructed atop the chinampas. Each chinampa, or “floating garden” as they have been erroneously
described, is between fifteen and thirty feet wide and 300 feet long and is no more than a few feet above the water
level (Coe 1964). Posts or woven vines and branches hold the sides of the chinampa plots in place. Chinamperos also
plant willow trees (Salix) on chinampa edges to prevent erosion. The word chinampa is derived from the Nahuatl words
chinamitl which means “‘an enclosed bed surrounded by cane or stakes’” and pan which translates to “‘on or above the
surface’” (Moriarty 1969).
Prutzman (1988) delineates seven steps in chinampa construction. First, chinamperos use a long pole to find an adequate
base for a chinampa and when possible use a cimiento, the remains of an old chinampa, as the foundation. Next, strong
reeds are “stuck” in the bottom to mark the base dimensions. Third, farmers dig mud from around the base and pile it
atop the reeds and cimiento. “Fourth, mats of water vegetation [are] cut and towed to the new chinampa.” These dense
vegetative mats or cesped were principally water lily and tule (Outerbridge 1987). “Fifth, a compost heap [is] created
by layering the mats of vegetation on top of each other until there [is] a thick cap of vegetation. Sixth, mud from the
bottom of the lake [is] mixed with soil from an old chinampa and placed on top, reaching a height of about one foot
above the water level. A porous base rich in organic matter [is] thus created through which water easily flowed.
Lastly, the sides [are] secured with woven reeds, and then willow trees, Salix bomplandiana, [are] planted around the
edges.”
An alternative view of chinampa construction is presented by Wilken (1985). Unlike Prutzman and others, Wilken asserts
that aquatic plants have no structural role in chinampas; rather, he believes that plots are constructed by “simply
extending drainage canals out into swamps or shallow lakes or back into low-lying shores” and then piling the excavated
material onto spaces between the canals. While the dredged mud inevitably contains aquatic plants, these plants are not
important structural component.
Regardless of which view of construction is correct, it is clear that chinampas are effective at drawing moisture.
Seepage from the surrounding canals keeps the soil continually moist at root level so as to provide crops with permanent
irrigation (Armillas 1971). If conditions became so dry as to not permit adequate infiltration, the chinamperos then
resort to hand-watering their plants.
The canals, which in the past provided the natives with an important part of their diet (fish, crustaceans, waterfowl,
salamanders), also serve as “thoroughfares” for the farmers’ flat-bottomed canoes (Coe 1964). To ensure that their
crops have a fertile matrix in which to grow, the farmers scoop mud from the lake bottom with a zoquimaitl (canvas bag
attached to the end of a long pole), transport the mud to the chinampa with their canoe, and then spread the mud on the
chinampa surface. This is done before each planting. Moreover, farmers often have a “favorite spot” for obtaining
nutrient-rich mud (Prutzman 1988).
Green manuring with aquatic plants was another traditional method for fertilizing the soil. After collecting the plants
in their canoes and bringing them to the chinampas to cut and dry, farmers would turn them into the soil green
(Outerbridge 1987). During the times of Aztec rule, chinamperos also used human waste to fertilize their plots. Bat
guano from the caves of Guerrero and Morelos was also incorporated into the system, primarily when sowing chile peppers
and tomatoes (Outerbridge 1987). Crop rotation and crop diversification were additional methods which promoted soil
fertility.
Chinamperos also periodically scrape off the surface soil of their chinampas (Parsons 1985). This action serves to
either remove soil that is “salt-charged” or to lower chinampa height so that crop roots can have adequate access to water.
The chinampa system is quite both labor and space intensive; farmers use minimal land very efficiently. With the
exception of maize, farmers do not sow seeds directly into their chinampas; instead, they use the technique of the seed
nursery or almacigo. Coe (1964) provides a clear description of this practice.
The nursery, at one end of the chinampa near a canal, is made by spreading a thick layer of mud over a bed of
waterweeds. After several days, when the mud is hard enough, it is cut into little rectangular blocks called chapines.
The chinampero makes a hole in each chapine with a finger, a stick or a small ball of rag, drops in the seed and
covers it with manure, which now comes from cattle but in Aztec days came from humans. For protection against the
occasional winter frosts the seedbed is covered with reeds or old newspapers. During dry weather the sprouting plants
are watered by hand. Finally each seedling is transplanted in its own chapin to a place on the chinampa, which has been
cultivated and leveled with a spade or hoe (the Aztecs employed a digging stick called a coa) and then covered with
canal mud.
Using a seed nursery is an integral aspect of the chinampa’s high productivity. Only healthy seedlings are transplanted
into a chinampa, so no space is wasted. Moreover, farmers time the harvesting of one crop with the transplanting of
another, so the chinampa is always in continual use. Year-round production ensures that farmers harvest at least two to
three crops a year.
As for the willows which line chinampa edges, they serve various functions in addition to maintaining mound structure
and preventing erosion. Planted at four to five meter intervals, the willows provide shade, serve as a windbreak, and
attract beneficial birds and insects. They also are a source of firewood and construction material.
All three images (chinamperos scooping mud, almacigo with individual
chapines, and chinampa cross-section) taken from Coe (1964).
[permaculture] (FWD) What is a chinampa,
Lawrence F. London, Jr., 01/19/2007