178 
EXPOSURE OF PLANTS. 
the oscular pores ; the juices are scalded, hence the tissues of thick-leaved plants 
are paralysed, and cease to perform their healthy functions. A northern aspected 
greenhouse is the preventive ; it constitutes the only safe habitat for such plants 
during summer, and without it a gentleman's establishment cannot be complete. 
Heaths, Epacrides, and the hair-rooted tribes, demand the same protective treatment 
as to aspect, but for these, dry, airy pits will be unobjectionable. Mr. Marnock 
meets another dilemma, and suggests its removal by a method which we have seen 
adopted, particularly in a fine conservatory belonging to the late Marquis Thomond. 
" The chief objection to plants being kept in the house during summer is that, 
exposed to the sun, the earth in the pots becomes dry, and the extremes to which 
the roots are subjected, cause the plants to assume a brown, unhealthy aspect, and 
some of the lower leaves to fall off. As a remedy nothing more is necessary than 
that an empty pot, which is intended to receive, and form a screen, for the pot that 
contains the plant, be sufficiently large to receive the latter within it, so that the 
tops of both be nearly level. I have," adds Mr. Marnock, "practised this for the 
last three years, both with stove and greenhouse plants, and during the dry weather 
of 1832, at least one hundred of the latter had their pots protected in this way. 
Those who cultivate tropical ferns will also find it of service in preserving the 
delicate roots of those plants from the effects of dry heat." 
We find these remarks in the " Gardener's Magazine " of 1834. It is refreshing 
thus to refer to the labours of the late Mr. Loudon, its assiduous editor. Thus, the 
article which immediately follows the one written by Mr. Marnock, contains matter 
that has been, and can again be, converted to great profit, and is equally relevant to 
the subject now under consideration. 
In the year 1833, the writer, who appears to have been a gentleman's gardener, 
tells us that he found, in 1827, a stock of seedling Rhodendron ponticum, left by 
his predecessor, amounting to several thousands. The plants were then in a 3-light 
frame, and in order to turn them to account three thousand of the largest were 
selected on the 28th of July following, and carefully lifted from the seed-bed with a 
little ball of earth attached to each. It is not so stated, but there can exist little 
doubt that this earth was the sandy heath-mould erroneously called " peat." As a 
preparatory step, a north border behind the forcing-houses had the original soil 
removed to the depth of fourteen inches, and the place filled with " peat earth." 
In this, the plants were set in nurse beds, the rows one foot asunder, the plants nine 
inches apart in the rows ; they were then plentifully watered with a pot and rose. 
The expense of preparing such a bed with " peat " being considerable, the gardener 
resolved to give the remaining stock (above 1500) a trial in the common light sandy 
soil of the garden. Part of a north border within the kitchen-garden was well 
dug, and the surface smoothly raked ; the best plants were then selected, and 
planted in rows across the border in distances as before ; a good supply of water was 
then given. Seven hundred of the worst plants still remaining, were placed among 
a young plantation of Filbert Trees, where the earth was similar, but the situation 
