May 27, 1869. ] 



JOURNAL OF HOBTIOULTUBE AND COXTAGK GARDENEK. 



351 



NIGHT TEMPERATURES DURING FORCING. 



[So much has liuen written recently on this subject, enforcing 

 views which we consider so erroneous and injui-ious, that on 

 the receipt of a letter from a correspondent, we sent it to Ml*. 

 Fish. We insert the letter with his commentary. — Eds.] 



O not let it be supposed from the tone of these 

 remarks that I am an enemy to free dis- 

 cussion, far from it, it is the "proving of all 

 things " that I wish most particularly to urge ; 

 but I do wish that some of our gardeners 

 would read more, and think more, would be 

 more particular in tracing efl'ect to cause 

 and cause to ellect, than they do before 

 giving their opinions publicity. It would 

 be much more to their credit, and would do 

 us all much more good when reading their opinions ; for, 

 really, of all the nonsense that ever I read I think this 

 high night temperature for the setting of Grapes bears the 

 bell. Eifect and cause, cause and efl'ect, are so hopelessly 

 muddled, that the result is " confusion worse confounded," 

 And the recklessness with which all the old-world theories 

 of vegetable physiology which we have been guiding our- 

 selves by, and ad\'ising our sons to study and copy, are set 

 at naught is amazing ; and, then, the mischief these opinions 

 do is almost incalculable. Employers who are fond of 

 gardening, and who take in " our .Journal," read these 

 opinions and records of experiments by practical men. To 

 them it looks and reads right, and as it comes through 

 The Journal of HoiixicuLTfiiK, it must be right, and then 

 the persecution which the poor gardener has to sutler, if 

 he happens to have an opinion of his own difl'erent to these, 

 is almost incredible, and, no matter what may be the real 

 cause of any failure he may have after this, it is all set 

 down to his ueglect of the advice of The Juuuxal of 

 Horticulture. Let me recommend these rash scribes 

 who dogmatise so about their little experiments to read 

 and study pages 201^ and 514 to 524 of Lindley's " Theory 

 of Horticulture," and pages 204 to 212 of the " Science and 

 Practice of Gardening," by Mr, Johnson, one of our own 

 Editors ; if they will read these pages, and think on them, 

 we shall not, I venture to say, be bored with the impossible 

 conclusions drawn from im.aginary premises which we have 

 been bored with for the last few weeks. — X. Y. Z. 



[Without at present referring to the authorities men- 

 tioned by "X. Y. Z.," I will base my opinion on my own 

 experience and conclusions. No doubt it is of great im- 

 portance to be very particular in tracing effects to causes, 

 but this may often prove to be a more difficult matter than 

 our correspondent supposes ; as not seldom, when I ima- 

 gined I had hold of the connecting link, farther experience 

 has proved to me that what I considered to be demonstrated 

 cause and effect was nothing more than a fortunate coin- 

 cidence. All such disappointments should teach us at 

 least a little charity when we review the opinions of others. 

 A man who finds he can set Muscat Grapes in a tempera 

 ture at night averaging from 00° to (i.5° should not be deemed 

 reckless if he recommends a lower night temperature than 

 that generally adopted ; and neither should that man be 



No. 426.— Vol. XVI., Ntw Series, 



deemed reckless who considers ho succeeds better than 

 common from having a night temperature of from 7.5° to 

 80°. Most probably if tho ploughshare of strict investiga- 

 tion were driven through such cases it would be found that 

 the Vines would have succeeded under either treatment, 

 or even in spite of it, I have set Grapes equally well in 

 a comparatively low as well as a comparatively high tem- 

 perature at night ; but in the low temperature at night I 

 was anxious that a higher temperature should be given 

 during the day when the stimulus to expansion would be 

 counteracted by the solidifying inlluences of light. 



Some day I hope to shake hands with '" X. Y. Z,," and 

 then shall look at liim hard to try and ascertain how many 

 years have passed over his head ; for to me it is sometliing 

 strange to have the liigh night temperatm-e alluded to as 

 something new, whilst the high day temperature and the 

 comp.ir.atively low night temperature are described as the 

 •' old-world theories of vegetable physiology." Why, in 

 my young days it was too " new " a " theory " to be much 

 thought about, and still less practised. In forcing in 

 general something like an equal average of temperature 

 was chiefly aimed at— or only a little more by day than 

 by night— just such a temperature as we might expect to 

 find near tjie ground in tropical latitudes, where the dense 

 growth of vegetation overhead prevented the ground being 

 suddenly heated by the sun or cooled by fi'ee radiation. 

 Frequently, from close shutting-up and covering, our good 

 and successful old gardeners gave their plants a higher 

 temperature in darkness than they did in the day, unless 

 the sun shone very brightly. The high temperature at 

 night is to me the " old-world theory." as well as contrary 

 to Nature ; and the letting temperature be regulated greatly 

 by light is to me the " new " as well as the natural theory. 



Be this as it may, it would bo idle to deny that by 

 adopting high temperatures at night grand results were 

 obtained. What I contend is that these results were ob- 

 tained by greater labour, and expense, and attention — by, in 

 fact, making one part of our practice couutel-act and modify 

 the other, just because, either ignorantly or knowingly, we 

 were opposing natural laws, instead of being guided by 

 them. I do not hint for a moment that in culture we 

 are to imitate the variations of the weather, &c. But we 

 may be guided by, instead of opposing the main principles 

 of vegetable growth : though we neither permit storms nor 

 tempests to get into our glass houses, the houses being built 

 for the very purpose of keeping all such intruders out. 



It is natural to all organised existence to repose in the 

 darkness. Even to man a sleep by day is not so refreshing 

 as a sleep by night. The plant, too, needs and must have 

 comparative repose. Kept continually growing in a high 

 temperature it exhausts itself, and wastes its powers pre- 

 maturely, and to go no further than the case before us, as 

 respects the Vine, is one fertile som-ce of shanking of bunch 

 and berry. Give a high moist temperature, and most free- 

 growing plants will elongate more in darkness than in 

 light. Continue the same stimulus to elongation by high 

 temperature in the day, and the sun will be unable to 

 consolidate the soft growth. Did our old gardeners know 

 all this ? Well, at any rate, they acted as if they did. 



No. 1078.— Vol. XLL, Old Slkils. 



