EXPERIMENTAL GARDEN. 555 



The main feature in keeping lawns is frequent mowing, and if tliis is neg- 

 lected fine lawns cannot be maintained. It will matter but little how much ex- 

 pense and skill may have been incurred in the preparation and seeding of the 

 ground if it is allowed to grow at random afterwards, as the strongest foliaged 

 grasses and clover will eventually supersede the finer kinds if the cutting is 

 not regularly attended to. On the other hand, lawns that have been but in- 

 differently prepared may be rendered close and regular by frequent mowing 

 and judicious top-dressing. 



Early cutting prevents the growth of the coarser grasses and induces lateral 

 growth on the finer, thus covering the surface with a dense foliage, which re- 

 sists the effects of sun and long-coutimied dry weather. 



Every lawn of any pretensions should be kept smooth by a machine. Not 

 only is it economical as regards labor, but it is scarcely practicable to keep it 

 Avith a scythe so smooth, thick, and velvety as can be done with a good lawn- 

 mower. Another advantage is that the grass is not removed, but falls down 

 in a shower over the roots, forming a very efiicient mulching, and enabling us 

 to impart to our pleasure grounds all the character of the finest lawns, an at- 

 tainment that has hitherto been deemed beyond our ability to realize. 



When the grass becomes thin and of weakly growth a top-dressing of good 

 stable manure should be laid over the surface in December. It is important 

 that the manm*e should be well rotted before being used, and as occasion offers 

 during winter it should be broken up and manipulated with an iron rake. The 

 object in view is to distribute it evenly over the whole surface. Break it finely, 

 so that it will settle down and nourish the grass roots. When spring opens, 

 the rough, strawy portions, if any are left, should be removed ; otherwise it 

 would interfere with the proper keeping of the surface. 



NIGHT TEMPERATURE IN GLASS STRUCTURES. 



One of the most prevalent and injurious errors in the management of green- 

 houses and other plant-houses is that of keeping the temperature too high 

 during the night. With many the aim seems to be to maintain as high a de- 

 gree of heat during darkness as during light, a practice opposed both by sci- 

 ence and the results of experience, and one that cannot be too severely con- 

 demned. 



It has been observed that plants will lengthen very fast during darkness in 

 a high, moist atmosphere, and it has therefore been supposed that a gain in 

 growth is thus secured, but strictly, this is not the fact. Any extension ot 

 growth made under such conditions is at the expense of that made during the 

 presence of light, as it is only then that those chemical changes are in opera- 

 tion that change the matters absorbed by the roots into the woody fibre and 

 other constituents of plants; consequently the same quantity ofmaterial is simply 

 elongated as in drawing out a wire, which may be lengthened without adding 

 anything to its structure. 



Plants grown in a nearly uniform temperature under glass seldom ripen or 

 mature their wood in a thorough manner, the buds are immature and make 

 feeble growth, and the whole plant contracts a delicate habit of constitution, 

 which renders it incapable of withstanding the slightest neglect without injury, 

 thus entailing great care to keep it even in its sickly condition, and never, by 

 any means, developing its natural capacities. On the contrary, plants con- 

 stantly subjected to a suitable lowering of night temperature are more robust, 

 have short-jointed and matured growths, flowers not only expand more fully, 

 but remain longer in perfection, fruits better colored and flavored, and more 

 perfect in every respect than those developed in an atmosphere of uniform 

 he<at and moisture. 



With regard to greenhouse plants, it should be remembered that they re- 



