Much 26, 1874. ] 



JOURNAL OF HOBTICULTUBB AND COTTAGE GARDENER. 



•251 



WEEKLY CALENDAR. 



GIVING AIK. 



HEN a yoimp; gardener lias leamt how to 

 give air properly to plant and fruit houses, 

 he has, in my opinion, mastered the most 

 difficult lesson in the whole of his very 

 difficult profession. To give air properly 

 means much more than merely to give 

 air when a house rises to a certain tem- 

 perature ; it means to give it in such a 

 manner as to maintain a genial atmo- 

 sphere, and at the same time to make 

 the most of the solar heat and light, so that the plants 

 may be grown in a more natural style than they are 

 where ventilation is not properly understood, and be so 

 hardy that none but those which naturally grow in shady 

 positions will require shade; also that a few degrees 

 below the regulation minimum for some hours before 

 daybreak wUl not harm them. We may be certain there 

 is something wrong somewhere if such plants as Cucum- 

 bers, Melons, or Tines require shading, unless it may be 

 for an hour or two on a sudden change from long-con- 

 tinued dull weather to very bright sunshine, and we may 

 be equally svire all is not right if on a sudden lowering of 

 the external temperature such plants as I have named 

 will not bear with impunity for a few hours in the night 

 a temperature of 53° or 55". 



The best place I can think of to prove whether a man 

 understands giving au- is a house with a steep roof facing 

 the east, and glazed closely with large panes, planted 

 with Alicante Vines, and where the temperature cannot 

 be raised by fire heat higher than 45°. Now, a man who 

 understands it can grow Grapes as good as it is possible 

 to grow them in such a structure, but one who does not 

 possess the requisite knowledge would probably have his 

 Vines bm'nt up the fii-st sunshiny day. I have named 

 Alicante because it is the first to show the effects of impro- 

 per ventilation on the fohage ; Lady Downe's and others 

 give their evidence principally in the shape of scalded 

 ben'ies. It was last year recommended by a very suc- 

 cessful Grape-grower to keep a high night temperature 

 by fire heat to prevent this scalding. I am aware it 

 would prevent it, and I am also aware it would encourage 

 insects, and, besides, it would be a very extravagant plan, 

 fit only for lazy people or those who are so aftiicted that 

 they could not move sharply for a few minutes in the 

 morning. 



To begin with : frait houses in which the occupants are 

 in a growing state should generally have air on night 

 and day. In those which are not glazed closely there 

 will, perhaps, be sufficient ventilation between the laps 

 at night. In very cold or very windy nights there will 

 be sufficient change of air taking place in any glass 

 structure, however closely glazed and shut ; but as a rule, 

 fruit houses are best with just a chink of air at the top. 

 In the morning one must be a little weather-wise, and 

 anticipate what is coming. If it is likely to be a bright 

 day fires must be stopped as early as possible, even 

 tliough the temperature be lower than the ordinary 



No. 67S.-Vot. XXVL, New Sebies, 



minimum. Air should be given without waiting for the 

 thermometer rising more than a degree or two — a little 

 at first, then watch a few minutes, and if the temperature 

 is stUI rising give a httle more ah-, and so on till as much 

 air is given as is likely to be wanted dm-ing any part of 

 the day. Never give enough air at one time to lower the 

 temperature, always anticipate the rising. For example : 

 say the night temperature should be 55° and the sun 

 temperature 90° to 100", which will suit all the plants I 

 have named — Vines, Melons, and Cucumbers. If by 

 chance the thermometer should only indicate 50° in the 

 morning it will do no harm, do not wait for it to rise 

 more than a degree or two before giving a little air, 

 merely be sm'e that it is rising, and that giving a little 

 air will not lower it. When it can be seen that it is still 

 rising, say by the time it reaches 55°, give more air, and 

 so on, getting all the air on that is likely to be wanted 

 by the time it indicates 60° or C5°. When the tempera- 

 tm'e rises gradually, with abundant ventilation in this 

 way, the atmosphere feels softer and more natural 

 throughout the day, evaporation is not so gi'eat, and the 

 houses do not feel so hot as the thermometers indicate 

 them to be ; plants do not flag, they have more sub- 

 stance in then- leaves, flowers are larger and of greater 

 thickness in the petals, the sexual organs are more fully 

 developed, and there is no difficulty about fertilisation. 



The foregoing directions apply principally to fine settled 

 weather. During the month of March, and at other timeB, 

 there are days when the weather changes every few 

 minutes, and it is very difficult then to manage forcing 

 houses : it is scarcely possible to give directions to meet 

 the requirements of such times, the knowledge how to 

 act can only be acquired by practice on the spot; but 

 speaking generally, a lowering of the temperature for an 

 hour by a passing cloud, or a httle higher rising than 

 usual by half an hour's bright sun, will not do so much 

 harm as is often done by giving a quantity of air suddenly 

 at the top of the house, and allowing the soft, moist, 

 warm air to be replaced by that which is cold and harsh. 

 Sometimes this difficulty can be met by giving air only 

 at the front or at one side of the house for a time, when 

 the evaporation will not be so rapid as if the upper part 

 of the house were open ; but in practice almost every 

 house we have to deal with requii-es special treatment. 

 — WiLLLA.M Taylor, Longleat. 



LAUEUS NOBILIS, OR SWEET BAY. 

 It is much to be regi-etted that this fine .shrub is not 

 so hardy as some others, yet there are many places 

 where it might be planted with advantage, and where it 

 worild be likely to answer all the purposes required of 

 an evergreen shrub. It is certainly more hardy than 

 most people think, for it is only now and then that a 

 hard winter tells upon it when it is planted in a situation 

 sufficiently dry to insm-e its shoots being properly ripened. 

 Amongst a number of plants here I do not think we have 

 lost one from the severity of the weather during the last 

 twenty years, although, twice or thrice, most of them have 

 been more or less injored ; stiU they have always recovered. 



No. 1330.— Vol. LI., Old Seejes. 



