March so, 1882. ] JOURNAL OF HORTICULTURE AND COTTAGE GARDENER. 253 
many people seem to imagine. It cannot be settled 
satisfactorily, as is attempted in some of our standard 
books, by merely obtaining the average temperature of 
any place abroad where such plants are known to thrive 
naturally. If we grow a plant for the first time, to 
know the conditions under which it thrives in its native 
habitat is a great 'help to us to start with, but there 
are so many local minor circumstances which cannot 
be imported with the plant, and the absence of which 
often neutralise to a great extent those conditions which 
are considered by cultivators to be all-important. I 
suspect the high temperatures which obtain in many 
establishments for Grape-growing came thus from a 
native source, for they cannot be the outcome of direct 
experiment, as that takes us, according to my experience, 
quite the other way. As high temperatures when not 
beneficial must do harm besides wasting fuel, the 
question to be settled is simply, What are the lowest 
temperatures in which Grapes sound in every way have 
been grown ? Now, I have seen Hamburghs and such 
other Grapes as are classed with them grown very 
fairly without any fire heat at all, such fruit being 
produced as most small amateurs would be thoroughly 
satisfied with, but this was in favoured localities, and 
the Grapes were not to be kept till the new year. It 
is, then, possible to grow Grapes without fire heat in 
certain districts and in certain seasons. It was, I 
believe, possible to grow them thus even in such a 
season as 1879, but if three such seasons had followed 
in succession it would not have been possible to con¬ 
tinue to produce presentable fruit in that way. Unripe 
wood two seasons following is sure to leave its mark, 
and in fruit-growing the coming year should always 
have a more prominent place in our minds than the 
present one. 
It is possible that a higher minimum temperature is 
necessary to northern latitudes for Grape-growing than 
that which may be safely practised in our southern 
counties ; and as evidence in favour of this, it is a gene¬ 
rally accepted fact that it takes a higher temperature 
to start Vines into growth during winter, however well 
ripened the wood may be, than it does during spring or 
autumn. Of course during spring we should expect 
the natural season to have some effect, but that does 
not account for all the difference; and supposing it is 
true that they also start comparatively easy in autumn, 
and I believe it is, we must look for a different explana¬ 
tion. I believe it is to be explained in the difference 
between the medium temperatures of the seasons and 
the length of time during the day in which the tem¬ 
perature keeps up to or beyond the medium height. 
Medium temperatures are generally taken only with 
regard to the highest and lowest points which the 
thermometers touch, and without any regard to the 
length of time the highest or lowest temperature pre¬ 
vails. Now for horticultural purposes this is not 
sufficient, it is the length of time during which a tem¬ 
perature not lower than the medium prevails which 
rules everything. It does no more harm to a Muscat 
Vine in flower to experience for half an hour a tem¬ 
perature of 45° than it does to the man who attends it, 
but that is no reason for recommending a temperature 
of 45°. The Muscat and every other Grape demands 
in order to bring it to perfection a certain number of 
hours of a certain average temperature. If the natural 
maximum ranges high, then a lower minimum may 
(under good hands) be safely practised ; and on the 
contrary, tvhen the maximum ranges low from being 
insufficiently assisted by natural causes, it may be 
necessary by artificial means to keep as high a mini¬ 
mum as is safe, and during daylight to make the 
temperature approach the medium as soon as possible, 
and thus artificially make up the necessary general 
medium which Nature denies us. I practised and 
recommended such a course as this during the dull wet 
season called the summer of 1879, and succeeded in 
ripening my fruit thoroughly when ripe fruit of late 
Grapes was scarce. If my reasoning is correct as to the 
different seasons it will also apply to different districts. 
There is another fact which seems to be overlooked. 
Thermometers are generally fixed in the most favoured 
part of a house. Now supposing a thermometer placed 
in the centre of a house and 6 or 8 feet below the 
Vines should indicate an average minimum tempera¬ 
ture of 70° during severe frosty weather, such as is often 
experienced in the north, there is no guarantee that the 
Vines are in that temperature. They may for aught we 
know experience at times a lower medium temperature 
than those of our friend on the Cornish coast, who boasts 
that he only allows a minimum of 45°; at any rate, 
situated as they are at some undefined position between 
fire and frost they cannot be so comfortable. I have 
when describing my trellis pointed out some of the 
effects of radiation, which at this point it may be 
advisable to the younger portion of my readers to again 
peruse. We must not, then, be too dogmatic in laying 
down rules for temperatures and other matters for 
everybody to follow under all circumstances. We may 
state truthfully our own experience in our own little 
sphere, and if during such statement a hint falls which 
isVorth anything, there are doubtless many ready to 
act on it, for all true gardeners are ever on the look¬ 
out for a lesson regardless of the quarter whence it 
comes, but none of them like it forcibly crammed down 
their throats. 
It is possible that before minimum temperatures 
anything like so low as those I succeed with can be 
practised safely in the north of Scotland, some better 
means must be found, by covering the roof or other¬ 
wise, of securing the desired temperature to the Vines 
as well as to the thermometer. We smile when Punch's 
old sexton discovers that he can by simply breathing 
on it raise the mercury of the newly introduced ther¬ 
mometer in the church to the desired point, and glee¬ 
fully relates his experience to the new curate. But I 
am afraid many of us still put too much confidence in 
the thermometer without sufficiently taking into con¬ 
sideration the surrounding circumstances. We can¬ 
not, however, do without the thermometer, and after 
many experiments I have settled down to something 
like the following temperatures, and believe them to 
be suitable for the southern and western counties of 
England, but I am never particular to a few degrees 
providing there is not at any time too much fire heat 
used. It must be remembered that my thermometers 
face the north and are all shaded from the sun, being 
placed in boxes for the purpose, the edges of which 
project along each side and over the top of the instru¬ 
ment about a couple of inches— 
For Starting. 
About 55° night and 
day, as far as fire 
beat is concerned. 
Flowering Period. 
57° to GO® night. 
G3° to 70° day. 
75° to 80° sun. 
After Flowering. 
G3° to 65° night. 
70° to 73° day. 
80° to 85° sun. 
A lower temperature than the lowest figure given 
