[8] As the season advances, and the sun becomes powerful, it will be necessary to shade them from the extreme violence of the heat. Mats are generally made use of, but the Author considers evergreen boughs far preferable, as the former entirely precludes the sun, whereas the latter is beneficial to the plants, in admitting it partially. This will be generally requisite from about ten until two; and at that time, in proportion to the degree of shade, a larger quantity of air must be admitted.