11. Enumerate the services rendered to the soil by humus.
12. In Experiment 10, let the corn grow for some time and determine whether the very rich humus is the best in the end. Sand and clay are almost altogether mineral; leaf-mould almost entirely organic; neither alone is good, but a mixture gives the best results.
GARDEN WORK
The boys of this Form should attend to the fertilizing and spading of the plots belonging to the girls of their Form. The girls themselves can do all the rest of the work, and they should try to keep the plots level, uniform in size, and in a straight line. If the corner posts are kept in line and the plots made up the exact size, the appearance of the garden will be greatly improved.
The pupils are now old enough to make their own choice of flowers and vegetables. Very tall growing plants, such as corn and sunflowers, are not desirable in individual plots as they shade other plants near them. Corn is best grown in a large plot about twenty feet square. The same may be said of vines, such as cucumbers, melons, squash, etc. If the plots are small, it is better to plant but a single variety, but in large plots from two to four varieties may be arranged to advantage. Usually rows of vegetables, such as carrots and beets, may be placed a foot apart, cabbage about twice that distance, and tomatoes a little farther apart than cabbage.
Generally speaking, plants should be placed so that when full grown they will just touch, cover the ground completely, and thus prevent the growth of weeds.
As soon as the young plants appear above the ground, light cultivation with rakes and claw-hand weeders should be started, so as to keep weeds from growing and at the same time to provide a loose surface or earth mulch for conserving the moisture and aerating the soil. Thinning should also be begun when the plants are quite small, but it should not all be done at once. As the plants increase in size, the best ones should be left and the poor ones taken out. In some cases plants thus removed may be re-set to fill vacant places.
TREE SEEDS
Tree seeds that have been stored over winter should now be planted in rows in a small plot. The rows should be a foot apart and the seeds quite close together in the row. A cheese-cloth or slat shade should be used on this plot, as the hot sun is too strong for tree seedlings when they first come up. They should have cultivation every week and watering in dry weather. Always water in the evening after school, or even later when possible.