The Jamestown colonists met with great discouragements. Most of them were unfitted for pioneers, and the neighboring swamps gave them malaria in the hot summer, so that nearly half perished. Smith, by his courage and enterprise, however, kept the colony alive and took charge, being their leader until captured by the Indians, and also afterwards, until his return to England. Among the first constructions at Jamestown were a storehouse and a church. These, however, were soon burnt, and a second church and storehouse were erected in September, 1608. This church was like a barn in appearance, the base being supported by crotched stakes, and the walls and roof were made of rafts, sedge and earth, which soon decayed. When Smith left Jamestown for England in 1609 the place contained about sixty houses, and was surrounded by a stockade. Smith early saw the necessity of raising food, and determined to begin the growing of maize, or Indian corn. Consequently, early in 1608 he prevailed upon two Indians he had captured to teach the method of planting the corn. Under their direction a tract of about forty acres was planted in squares, with intervals of four feet between the holes which received the Indian corn for seed. This crop grew and was partly harvested, a good deal of it, however, being eaten green. Thus the Indian invented the method of corn-planting universally observed in the United States, and this crop of forty acres of 1608 was the first crop of the great American cereal grown by white men. Wheat brought out from England was first planted at Jamestown in 1618 on a field of about thirty acres, this being the first wheat crop grown in the United States.