It has been previously indicated (76) that humus in large amounts is essential to success in every line of vegetable gardening and that stable manure supplies it in the best form. While this is true, it is impossible for thousands of commercial growers to secure enough stable manure to maintain the productiveness of their soils. This is particularly true of truckers living remote from great centers of population. It is easy enough for gardeners operating a few miles from the city to secure sufficient manure to produce good crops, but it is quite a different proposition for the grower living hundreds of miles from available supplies. It is impracticable for extensive truckers to use very freely manure which costs as much as $3 a ton spread on the land. In many trucking sections it is not only much more economical to maintain the necessary amount of vegetable matter in the soil by the use of green crops, but it is also an effective means of keeping the soil in the proper sanitary condition.