The depth of planting must vary with the character and size of the seed. English peas may be covered six inches deep and will be all the better for such covering, but if corn be covered so deep, it hardly gets above the ground. In planting small seeds like those of the radish, cabbage, turnip, lettuce, etc., a good rule is to cover them three times the thickness of the seed. In sowing seeds when the ground is rather dry, it is a good plan, after covering them, to tramp on the row so as to press the soil closely to the seeds and to help it to retain moisture for germination, but do not pack the soil if it is damp. In spring never dig or plow the garden while it is still wet, but always wait until the soil is dry enough to crumble freely. =What Crops to grow.= The crops to be raised will of course depend upon each gardener's climate, surroundings, and markets. Sometimes it may pay a grower, if his soil and climate are particularly suited to one crop, to expend most of his time and energy on this crop; for example, in some sections of New York, on potatoes; in parts of Michigan, on celery; in Georgia, on watermelons; in western North Carolina, on cabbage. If circumstances allow this sort of gardening, it has many advantages, for of course it is much easier to acquire skill in growing one crop than in growing many. [Illustration: FIG. 88. A LARGE YIELD OF CABBAGES] On the other hand, it often happens that a gardener's situation requires him to grow most of the crops known to gardening. Each gardener then must be guided in his selection of crops by his surroundings. =Care of Crops.= The gardener who wishes to attain the greatest success in his art must do four things: First, he must make his land rich and keep it rich. Much of his success depends on getting his crops on the market ahead of other growers. To do this, his crops must grow rapidly, and crops grow rapidly only in rich soil. Then, too, land conveniently situated for market-gardening is nearly always costly. Hence the successful market-gardener must plan to secure the largest possible yield from as small an area as is practicable. The largest yield can of course be secured from the richest land. Second, the gardener must cultivate his rich land most carefully and economically. He crowds his land with products that must grow apace. Therefore he, least of all growers, can afford to have any of his soil go to feed weeds, to have his land wash, or to have his growing crops suffer for lack of timely and wise cultivation. To cultivate his land economically the gardener must use the best tools and machines and the best methods of soil management.