I transfer from my Treatise on Onions, a paragraph relative to
growing Carrots with onions.
The plan of raising Carrots with onions is considered an improvement
by some who have adopted it, as the yield of Carrots is thought to
be clear gain, diminishing but little or none the yield of onions.
Carrots are planted in two ways; one by sowing them in drills between
every other row of onions, and the other, which is considered an
improvement, called the Long Island plan, by planting the onions in
hills from seven to eight inches from center to center, dropping
a number of seed in each hill, and from the first to the twelfth
of June, planting the Carrot seed, usually by hand, between these
hills in two rows then skipping one, and thus on through the piece.
The onions, as they are pulled are thrown into every third row, the
Carrots being left to mature. By this method from two to six hundred
bushels of Carrots are raised per acre in addition to the crop of
onions. More manure is required for the two crops than for the onions
alone.
The machine used for sowing in drills has two boxes attached to
the axle at equi-distance from the wheels; there are three or four
holes in the axle that communicate with the seed in the boxes, and
as these holes pass under the boxes they are filled with seed, and
as they turn the seed are dropped into the earth. Screws are sunk
into the holes, which can be sunk more or less at pleasure, and the
quantity of seed which the holes will contain is thus graded.
The machine should first be tested, and so regulated that on a barn
floor it will drop from eleven to twelve seed from each hole. When
so regulated, on using in the field it will drop but from seven to
twelve, owing to the more uneven motion.