402 



HENDERSON'S HANDBOOK OF PLANTS. 



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portant conditions to the well-being of 

 plants under cultivation, and the nearer 

 we can come to the conditions of tem- 

 perature and moisture of the native hab- 

 itat of the plant, the nearer we come to 

 perfection in cultivation. Thus we find 

 that in our garden weeds, the Chickweed 

 (Alsine or Stettaria media) is only trouble- 

 some in early spring and in the fall, when 

 the average temperature is perhaps 50 

 or 60, because it is a native of a country 

 (Britain) where there is no higher aver- 

 age; while our too familiar Purslane 

 (Portulaca oleracea) only rears its head to 

 injure in the dog days, when the ther- 

 mometer averages 70 or 80, because it 

 is an importation from the tropics. 



A large proportion of Lima Beans, 

 Sweet Corn, and other tropical vegetable 

 seeds annually perish by being sown two 

 to three weeks too early by our impatient 

 amateur horticulturists; while, on the 

 other hand, the colder blooded Parsnip 

 or Carrot all but refuse to germinate, 

 and often fail to grow in the hot summer 

 weather. Seeds of Calceolarias, Cinera- 

 rias, Primroses, Pansies, etc., which in 

 England are sown and germinate freely 

 in July, will in a majority of cases utter- 

 ly fail if attempted at the same date 

 here, where we have 15 to 20 higher 

 temperature and a drier atmosphere. 

 "We hear of hundreds of failures of this 

 kind every season, which are laid to the 

 quality of the seeds by Scotch and Eng- 

 lish gardeners, who have not yet had 

 experience with our American climate. 

 The same seeds, sown during the months 

 of Februar}% March, or April, or Septem- 

 ber or October, would germinate without 

 trouble, because the temperature and at- 

 mosphere then can be made inside con- 

 genial to their nature. 



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The same necessity for congenial tem- 

 perature exists in growing matured 

 plants, and one of the main causes of 

 want of success in cultivating plants un- 

 der glass is a want of knowledge, or care- 

 lessness in keeping a temperature un- 

 suited to the growth of the plants. In 

 ordinary green-house collections the fault 

 is oftener in the temperature being kept 

 too high than too low, for it is usually much 

 easier, requiring far less watchfulness 

 by the person in charge to keep up a 

 high temperature. The injury done by 

 this is gradual, and will not, like the ac- 

 tion of frost on the plants, show in the 

 morning. In consequence of this, we 

 often see the green-houses containing 

 Camellias, Azaleas, Pelargoniums, Carna- 

 tions, etc., sweltering under a continued 

 night temperature of 60 or 65, when 

 their nature demands 15 lower. In 

 large establishments, where there are a 

 number of green-houses, this is made an 

 easy matter by placing the proper num- 

 ber of four-inch pipes in a green-house 

 to suit the different temperatures; for 

 example, in our own establishment, where 

 our houses are uniformly twenty feet 

 wide, for a temperature of from 35 to 

 40 in coldest weather, we use four runs 

 of pipes, that is, two pipes on each side; 

 for 40 to 45 we use five pipes; for 45 

 to 50 we use six pipes; for 55 to 60 

 we use eight pipes; and for 65 to 70 

 we use ten pipes. 



It is true, we too often see collections 

 of hot-house and green-house plants in- 

 termingled, and attempts made to grow 

 them, which, of necessity, result in failure 

 to one or the other. The temperature to 

 grow, in healthy condition, Dracaenas, Cro- 

 tons, Coleus, Bouvardias, or Poinsettias, 

 (hot-house plants,) would not be likely to 



