474 
JOURNAL OF HORTICULTURE AND COTTAGE GARDENER. 
[ Jane 7, 1888. 
gardens and maintain regular supplies of the different kinds of produce 
-required by their owners. The scholars after their training find employ¬ 
ment as best they can as landscape gardeners, not as cultivators ; and 
as affording slight testimony of the value of our ‘‘rude” system of 
training men without technical schools, the fact may be recorded that 
of the two best managed private grrdens I have seen in Belgium, one is 
in charge of a Britisher, and the other of a native, who was taught 
English in order that he might read the Journal of Horticulture, for 
learning English work and ways, which he represents very well on Bel- 
■gian soil. So here against the theory of some of our “ school ” advo¬ 
cates, and most excellent men, we have the practice of King Leopold 
and his loyal subject, and great amateur horticulturist, Mr. J. Everaerts, 
who did not go to a “ school of horticulture ” for their; [gardeners.— 
A JUEOE. 
PLUNGING PLANTS. 
t A paper read by Mr. Wm. Eardnoy, Korri.s Green Garden?, before the members of the 
Liverpool Horticultural Association.] 
We have to consider whether plants can be grown better with their 
pots protected from atmospheric conditions by plunging them in tan, 
cocoa-nut fibre refuse, sawdust, ashes, soil, or any other material, or by 
growing them with their pots fully exposed. What are the advantages 
fco be gained by a general system of plunging ? and what are the; dis¬ 
advantages that can reasonably be urged against it ? I shall contend, 
then, that it should be practised for the economical advantages it offers. 
If gardening is to prosper in the future the cost of production must be 
.duly considered, so that the returns will justify the outlay. If labour 
.can be saved by plunging, why persist in growing plants with their pots 
exposed ? Appearance will always have to be considered in gardens as 
well as economy, whether in private or trade establishments. What 
renders plant houses more disagreeable and unsightly than dirty stages 
and pots ? The work of keeping the pots clean is considerable, which by 
plunging would be entirely dispensed with. There would be no stage¬ 
washing, for open trellis staging is not yet obsolete, but it should be. 
If gravel is used it soon becomes green, and entails as much labour in 
washing or renewing as the plunging material would cost. The labour 
of pot-washing is saved, practically so, for what will have to be done is 
reduced to a minimum. When the pots are constantly exposed they 
soon present an unsightly appearance, and they are no sooner washed 
than they are green again. Use ordinary pots, follow a system of 
plunging them, and this laborious sj'stem of pot-washing will be 
dispensed with. 
But the labour saved in this matter so far, is not to be compared 
with that saved in watering. Watering, to do it well, is, perhaps, the 
most expensive item in the production of plants when grown on the 
ordinary methods with their pots exposed. The labour can scarcely be 
estimated, for so much depends upon the supply, and whether it is close 
at hand or the reverse. By plunging the pots evaporation is arrested, 
and very little moisture is drawn from the soil in which the plants are 
growing. When the surface of the soil and pot is covered very little 
moisture escapes, only what is naturally evaporated from the leaves and 
stems of the plant. Evaporation will go from the surface of the plung¬ 
ing material, but if a judicious system of syringinsr is followed daily as 
the state of the atiEosphere and the requirements of plants demand it is 
replaced. To do this does not require one-tenth the labour entailed in 
watering when plants are grown on the usual principle. Not only cau' 
plunging be proved to be economical, because it saves labour in pot-- 
washing and in watering, but because there is a corresponding saving of 
food provided for the plant within the limit of the pot. I think it 
cannot be disproved, or even doubted, that rain will wash down into the 
earth, and often below the reach of the roots of plants, to be carried 
away in the drains, much of the essence of manure when applied in 
autumn, even if placed on the surface of the soil. Of course considerably 
more will be lost, if I may use the term, on light than heavy sotl.s. 
What is the rainfall of our climate in comparison with the amount of 
water poured into the soil of plants when they are grown with their 
pots exposed ? I contend, then, that giwving plants with their pots 
exposed to the atmosphere results in the waste of more food from the 
soil than is taken up and utilised by the plant, in fact more than is really 
needed to carry out its proper functions to sustain health and vigour. 
It may be argued that the requisite food can be supplied to the surface, 
as I readily admit, but it strengthens my argument that a system of 
culture should be adopted by which the food supplied to the plant when 
it is potted can be retained for the plant’s use, and pot washed away. 
This can be accomplished by plunging, evaporation is thereby arrested 
to a large extent, and it is not necessary to pour one-tenth the quantity 
of water into the pot. The food placed within the pot at first is suffi¬ 
cient, then, for the plants for a much longer period than would be the 
case if watered as many times as becomes necessary when they are 
grown with their pots exposed to the atmosphere. 
In further considering the benefits that result from plunging, it is 
evident the system provides the most uniform condition about the roots 
both as re.gards moisture and temperature. By the ordinary method of 
watering this cannot be done, for the soil is seldom in that satisfactory 
condition ; it is either wet or dry, and the.y need water during dry: 
weather two and three times a day, more or less according to external 
conditions. 
I have said that by plunging a more uniform temperature about the 
roots is maintained. vSome may deny this, and point to the genial 
warmth that encircles the pots in our glass structures. But we must not 
overlook the fact that they cool in a corresponding manner. The 
variations of temperature to which the roots are subjected are greater 
then than can possibly be. the case when the pots arc buried beneath 
the surface. The roots beneath the surface may not become so warm by 
day as those fully exposed, but they are warmer at night. To be under¬ 
stood I will put it in simple form. A pot exposed will become frozen all 
round it, not only on the surface, while the one plunged would only 
freeze on the surface, this is supposing they are exposed to a moderate 
frost only. By plunging the pots are protected from extreme heat and 
cold, more in accordance with the conditions provided for plants in a 
natural state. 
If we turn to plants grown in glass houses and plunged, it may be 
pointed out that those in large pots would be much cooler at their base 
than they would on the surface. There would unquestionably be a 
difference, as great as exists when plants are growing in a state of 
nature. If they are cooler by day they have the advantage by night—that 
is in a natural state ; but under our artificial system they would be 
cooler at all times below than on the surface unless bottom heat was 
employed. The use of bottom heat and plunging would appear by the 
statements of some cultivators to be inseparable. I intend to separate 
them, for bottom heat need form no connection with the system of 
plunging I am bringing before you. I do not advocate the employmeht 
of deep brick beds in the centre and sides of houses for the purpose of 
carrying into effect a system of plunging. I object to these brick beds, 
in the first place because they prevent providing for the roots of plants 
the uniform temperature desirable; secondly because the two outer- 
beds, part of them at least, are exposed to the cooling condition of the 
external air. Plants near the outer wall would, during cold weather, 
be many degrees cooler than those nearer the path ; in fact, they would 
be too cold to insure their doing well. Thirdly, because it obstructs the 
means of evenly distributing the hot-water pipes. These objeetions 
alone are sufficient to guide us to consider whether arrangements cannot 
be provided by which these objections can be overcome without adding 
to the expenses of construction and production. ■ • i 
The beds for plunging should be provided on the same principle as 
the side stages of our houses when erected with legs of iron connected 
with angle irons secured to them at the back and front, leaving a clear 
space at the back so that the heat from the pipes can pass up. The 
central bed would be constructed on the same principle, with the pipej 
distributed below it. I need not enter into details how large pots corud 
be plunged on this principle without the front .edges looking untidy, by 
a thick layer of plunging material, or a deep edge that could M 
furnished in a more striking manner than is the case at present if the 
structures were required for ornamental purposes instead of for growing 
on. This plan would provide for the roots being as warm at the base as 
at the top, because slates absorb heat to such an extent that they quickly 
become thoroughly warm. It is radiated under certain circumstances 
equally as quick, and slates are therefore the most objectionable base 
that can be employed for plants if the pots are stood upon them in cool 
structures without grave,J or some other material. The last is nq part of 
our subject, and is only alluded to in passing because such objectionable 
practices are persisted in, and the gardener often blamed because plants 
fail to do well on them. The new Vine house at the Aigb.urth Nurseries 
is exactly to my fancy as far as the distribution of the heat is concerned, 
and the method of plunging that was adopted with the'Vines early in 
the season. The arrangements are worthj- of special npte, because they 
have been the result of careful thought and consideration. 
Pluno-ing the pots is advocated because it protects the roots from 
injury. °How quickly are the silk-like roots of many plants injured 
when the pots arc exposed to the sun and the drying conditions of the 
atmosphere ! Even when the sun has but little power, moisturp from, 
the pot and soil is evaporated at such an enormous rate that injury to 
the roots in a greater or less degree can scarcely be prevented. Who 
has not protected the pots of Heaths, Azaleas, and other hardwooded 
plants on the sunny side to prevent the roots being ruined by the heat 
the pot naturally absorbs ? Why is this done ? Such practices strengthen 
my argument that the protection of the pots insures the roots of the 
plant against injury. If we consider the roots as “absorbent organs,” 
every precaution should be taken to preserve them. Injury to the roots 
means a check to the plant, the evils of which may not be perceptible 
for some time. I believe that the foliage of more Heaths is browned, 
and eventually falls, while Azaleas lose before flowering a greater per¬ 
centage of the'ir leaves by injury to the roots through the exposure of 
their pots than from any other cause. 
By plunging plants earlier, quicker and increased root activity is 
ensured, and in consequence a better and more luxuriant growth follows. 
To prove this take two cuttings equal as far as the wood is concerned, 
make them of equal weight, and put them into the propagating box to 
root say two Crotons. Treat them to the same- heat and atmospheric 
conditions, only one must be plunged, covering the rim and surface of 
the soil. When rooted place them in 5 or G-iuch pots, plunge the one 
again and grow the other without for a time. Now, turn the two out 
of their pots, wash the soil from their roots, and when thoroughly 
drained weigh them, and it will be found that the one that has been 
plunged has not only the most roots, but will be the heaviest. The one 
may be w.atered and the other given none after it is rooted, provided 
the soil is in an intermediate state of moisture when potted and the 
plnnging material is kept moist. An example may be given to show 
the difference in the supply of w-ater needed when they are plunged 
and when they are not. 1 have rooted Crotons in 2-inch pots, and they 
have been repotted until they were placed in 10-inch pots, and filled 
