Before taking up the garden vegetables individually, I shall outline the general practice of cultivation, which applies to all.
The purposes of cultivation are three to get rid of weeds, and to stimulate growth by letting air into the soil and freeing unavailable plant food, and by conserving moisture.
As to weeds, the gardener of any experience need not be told the importance of keeping his crops clean. He has learned from bitter and costly experience the price of letting them get anything resembling a start. He knows that one or two days' growth, after they are well up, followed perhaps by a day or so of rain, may easily double or treble the work of cleaning a patch of onions or carrots, and that where weeds have attained any size they cannot be taken out of sowed crops without doing a great deal of injury. He also realizes, or should, that every day's growth means just so much available plant food stolen from under the very roots of his legitimate crops.
Instead of letting the weeds get away with any plant food, he should be furnishing more, for clean and frequent cultivation will not only break the soil up mechanically, but let in air, moisture and heat all essential in effecting those chemical changes necessary to convert non- available into available plant food. Long before the science in the case was discovered, the soil cultivators had learned by observation the necessity of keeping the soil nicely loosened about their growing crops. Even the lanky and untutored aborigine saw to it that his squaw not only put a bad fish under the hill of maize but plied her shell hoe over it. Plants need to breathe. Their roots need air. You might as well expect to find the rosy glow of happiness on the wan cheeks of a cotton-mill child slave as to expect to see the luxuriant dark green of healthy plant life in a suffocated garden.