ii8 



IRISH GARDENING. 



AUGUST 



I lothcds. 



AIIOTniin is used by i^ardeners as a 

 con\ ciiiont iiuiihator lor raisin*,^ yount,'- 

 plants. It supplies tlie needful warmth 

 duriui,^ a period ot the year when the natural 

 temperature o( the air and soil is too low to 

 induce {germination and j^iowtli. Uy providing- 

 artificial heat durinj;- the seedling; period, many 

 weeks are gained in earliness of crop. The 

 cost of making- a hotbed is really so trivial in 

 comparison with its advanlag-es that it is 

 surprising amateurs do not make more use ot 

 such an easy and interesting- means of raising- 

 all sorts of flowers and vegetables. 



The temperature required to start and main- 

 tain germination differs of course with different 

 kinds of plants. It is well known that the 

 seeds of most Alpine plants can germinate at 

 or near the temperature of ice. The growing 

 tips of all plants breathe, that is, they have 

 the power of burning (hence the need of 

 air) — the soluble food in their sap. This slow- 

 process of burning in a wet way releases a 

 certain amount of heat, and there are certain 

 Arctic plants the root-tips of whose seedlings 

 can gradually melt the ice so that the roots can 

 penetrate into it along channels they melt out 

 for themselves. But plants of this hardiness are 

 relatively few. The very lowest temperature 

 at which the seeds of ordinary cultivated plants 

 will show signs of germination is somewhere 

 about 5 degrees above frost. But many require 

 a higher minimum — sunflower, for example, 

 demands 8 degrees or lo degrees centigrade, 

 tobacco about 15 degrees, and cucumber or 

 melon about 18 degrees. These temperatures 

 represent the lowest, the best temperature is 

 of course much higher. Speaking generally 

 with respect to our ordinary cultivated plants, 

 the best temperature would be somewhere 

 around 40 degrees centigrade. 



The object of a hotbed is to supply the most 

 favourable temperature to germinating seeds 

 and seedlings. The heat is generated by taking 

 advantage of the natural heat given off from 

 fermenting stable manure. For the intelligent 

 management of a hotbed, the user must clearly 

 understand the w/ty of fermentation. The heat 

 is really generated in the same way and by the 

 same process as that generated in a market 

 crate closely packed with chickens. It is a 



natural heat, given off by living breathing 

 things. The horse droppings used in the mak- 

 ing ol a hotbed aie swarming with uncount- 

 able myriads oi iiuisible bacteria. These 

 bacteria feed, grow , and nuiltipl)' in the organic 

 matter of the dung- and give ofl, all told, a pro- 

 digious quantit}- of heat which is to a large 

 extent held by the solid matter of the manure. 

 They require for their activities a certain 

 amount of moisture and air. By keeping the 

 heap loose you can hasten the fermentation, by 

 keeping it closely packed down you can check 

 the action, because in the latter case you 

 exclude air, and in a poor supply of air breath- 

 ing (that is burning) can only proceed very 

 slowly indeed. You can therefore regulate the 

 natural temperature of your bed as easily as 

 in an artificially heated greenhouse, where, by 

 regulating the damper you can control the 

 consumption of fuel. 



Now as to the making ot a hotbed : — 



When there is a choice of exposure select .south- 

 eastern or southern with some protection on the north 

 or north-west. This protection may consist of build- 

 ing's, evergreen trees or some constructed wind-break, 

 and at the same time have the lied fully exposed to 

 the sun throughout the day. 



The heat, as we have already explained, is supplied 

 by fermenting horse dung which should be collected 

 from the stables every few days and stored where it 

 will keep dry, or it may be taken directly from the 

 stalls. A sufficient quantity must be on hand before 

 the time for building the hotbed. The manure, which 

 should have mixed with it one-third or one-half its 

 quantity of leaves or short straw, is thrown into a well- 

 trodden conical heap. If the materials are dry sprinkle 

 over each layer enough water to thoroughly moisten, 

 but not to sodden, the mass. The heap will soon begin 

 to " smoke," which indicates its heating. When this 

 has been goingf on three or four days the whole heap 

 must be chopped down and forked over thoroughly and 

 again thrown into a conical heap. A few days later 

 the chopping and forking is repeated and the manure is 

 again piled and will be ready for the hotbed in ten 

 or fifteen days from the time its preparation was 

 begun. 



The frame or box can be made by anyone gifted with 

 the use of saw and hammer, and consists of a box 16 or 

 18 inches high at the north side and 12 inches on the 

 south, the ends conforming to the pitch. The width is 

 6 feet from outside to outside, and maybe of any length 

 desired to accommodate any number of sash. At 

 intervals of 3 feet 2-inch strips should be let into sides 

 flush with the upper edges for the sash to rest on and 

 to prevent the sides from spreading. These strips are 

 6 feet long and extend across the frame. Remove 20 

 or 30 inches of earth from within the frame, filling this 

 space with the manure well tramped in. For several 

 days immediately after the manure is put in it should 



