The plough idea has nowhere been found to answer, and is exploded.[23] Still, even for hand labour to cultivate, and for facilities in picking leaf, it is necessary there should be room enough one way to pass along. Cultivation here means digging, and space enough for this must be left between the lines. Giving so much, what is then the principle that should guide us? Clearly, with a view to the largest yield obtainable, to place as many plants on the land as it will bear. Four or 4-1/2 feet are, I think, the best distances between the lines. They give space enough for air to cultivate, and to pass along, even when the trees are full grown. Where manure is obtainable and the soil can be kept up to a rich state by yearly applications, a garden can scarcely be planted too close. I see no objection to trees touching each other in the lines. On considerable slopes, to prevent the wash of soil, the plants should be placed as close as possible, say 3-1/2 feet between and 2 feet in the lines. A closely planted garden will grow less weeds than a widely planted one, and will consequently be cheaper to work. As the expenditure on a garden is in direct proportion to the area, and the yield in direct proportion to the number of plants (always supposing there is power enough in the soil to support them), it follows that a closely planted garden _must_ be very much more profitable than the reverse. Hybrid plants grow to a larger size than Chinese, and should therefore have more room. The following is a useful table:-- _Table showing the Plants to an Acre, and the Area one lakh of seedlings will cover, at the distances named._