90 
JOURNAL  OF  HORTICULTURE  AND  COTTAGE  GARDENER. 
Febiuary  4,  1897. 
TUBEROUS  ROOTED  BEGONIAS  FROM  SEED, 
The  value  of  tuberous  Begonias,  both  as  greenhouse  decorative 
plants  and  bedding  plants,  ii  now  fully  recognised.  Both  the 
double  and  sing’e  varieties  are  equally  useful  for  either  purpose. 
The  doubles,  perhaps,  find  the  most  favour,  because  the  individual 
blooms  are  compact,  bright  in  colour,  and  attractive.  For  button- 
hole  flowers  the  double  varieties  are  hard  to  surpass,  and  are 
frequently  grown  for  furnishing  neat  and  effective  flowers  for  this 
purpose,  as  well  as  affording  decorative  plants  of  the  highest  value. 
The  single  varieties  produce  very  large  flowers.  Good  plants  of  a 
floriferous  character  and  bushy  habit  are  showy  and  effective  for  a 
considerable  period  during  the  summer  months  in  the  greenhouse. 
Among  them  there  is  a  wide  range  of  colour,  including  shades  of 
white,  blush,  yellow,  crimson,  and  red. 
Both  erect  and  drooping  growers  are  found  among  Begonias. 
The  erect  growing  varieties  are  obviously  the  best  for  pot  culture  ; 
the  drooping  for  ba»kets,  which  may  be  suspended  from  the  green¬ 
house  roof.  With  good  cultivation  and  attention  in  affording  due 
supplies  of  moisture  to  the  root*  during  dry  weather  luxuriant 
growth  will  be  made.  The  growths  and  blooms  depend  from  the 
baikets  in  a  most  graceful  manner. 
A  collection  of  Begonias  is  interesting  as  regards  the  foliage, 
which  varies  in  shape  and  hue,  also  marking*,  which  render  the 
plants  attractive  in  this  way.  The  more  freely  the  plants  grow, 
provided  the  growth  is  made  under  favourable  conditions,  the  better 
they  flower,  as  bloom*  are  continually  being  produced  from  the 
new  growths.  Tuberous  Begonias  are  essentially  summer-blooming 
plants,  and  by  no  meaos  can  they  be  made  to  bloom  during  winter, 
or  to  grow  and  flower  continuously. 
Raising  Plants  from  Seed.— There  is  little  difficulty  in 
securing  a  collection  of  good  varietie*  in  a  wide  range  of  colour 
and  form  by  raising  plants  from  seed.  The  seed  it  extremely  small 
and  requires  extraordinary  care  in  sowing,  so  that  by  no  mishap 
shall  the  tiny  pinch  of  dust-like  particles  be  lost  in  the  process  of 
transferring  them  from  the  Is.  6d  ,  2s.  6d.,  3s.  6d.,  or  5s.  packet  to 
the  surface  of  the  seed  pot  or  pan.  Small  seeds  like  Begonias 
must  have  specially  prepared  surfaces  on  which  to  germinate  readily 
and  grow  freely.  Procure  clean  dry  pots  5  or  6  inches  in  diameter, 
or  shallow  pans  of  larger  area.  The  pots  should  be  half  filled  with 
drainage,  the  pans  not  needing  quite  so  deep  a  layer  of  potsherds 
or  crocks.  Keep  the  drainage  clear  of  soil  by  a  protecting  layer 
of  damp  moss,  or  fibre  from  the  comport  ;  on  this  place  the  prepared 
material  for  sowing  the  seed  upon.  This  must  consist  of  sweet 
ingredients — equal  parts  of  fibrous  sandy  loam,  decomposed  leaf 
soil  and  silver  sand,  thoroughly  well  mixed. 
In  order  that  the  compost  may  be  known  to  be  absolutely  free 
from  insects  or  worms  the  whole  prepared  material  ought  to  be 
scorched  on  a  hot  plate  or  shovel.  After  this  process  moisten  the 
compost  with  sprinklings  of  warm  water,  mixing  to  a  pleasantly 
moist  condition.  It  will  then  be  ready  for  use.  Place  it  in  the 
receptacles  fairly  firm,  and  level  the  surface  with  something 
smooth.  It  is  desirable  to  still  further  moisten  the  compost  by 
standing  the  pot  or  pan  in  tepid  water  until  some  begins  to  rise 
through  the  surface,  but  before  this  becomes  evenly  wet,  withdraw 
and  allow  the  soil  to  drain. 
I  ought  to  have  stated  previously  that  the  material  must  be 
riddled  fine,  especially  so  on  the  surface  where  the  seed  ha*  to 
rest.  Scatter  the  seeds  evenly.  If  any  attempt  is  made  to  cover 
them,  the  slightest  film  possible  of  sand  only  should  be  applied. 
The  seed  frequently  germinates  well  without  any  covering  of  soil. 
Cover  the  pot  or  pan  with  a  sheet  of.gla*s  to  prevent  evaporation, 
and  oyer  that  lay  paper  or  moss  to  darken  the  soil.  The  next 
point  is  the  selection  of  the  position  for  placing  the  seed  re¬ 
ceptacles.  Both  top  and  bottom  heat  is  requisite  to  command 
success.  The  best  place  is  a  propagating  frame  in  a  forcing  house 
or  stove  where  a  constant  temperature  of  65°  to  70°  is  maintains  d. 
Moist  surroundings,  too,  are  imperative.  Any  undue  drying  of 
the  pots  or  soil  may  jeopardise  the  process  of  germination.  The 
temperature  named  just  affords  that  gentle  stimulus  which  causes 
activity,  and  in  the  course  of  a  few  weeks  if  the  temperature  is 
regularly  maintained  many  young  plants  will  appear.  Not  all, 
however,  will  do  so  as  early  as  this,  but  in  due  course  a  large  per¬ 
centage  ought  to  germinate.  If  moisture  condenses  too  freely  on 
the  glass  at  any  period  wipe  it  dry. 
The  darkening  material  must  be  removed  immediately  the  first 
seedlings  appear,  but  the  glass  may  be  kept  over  the  pots  or  pans 
until  the  tiny  plants  acquire  some  strength,  when  it  may  be 
gradually  removed.  The  seedlings  require  pricking  out  into  fresh 
compost  long  before  they  are  of  sufficient  size  to  handle  with  the 
thumb  and  finger.  Their  removal,  however,  may  be  managed  by 
means  of  a  small  notched  stick  inserted  under  them  to  lift  them 
out  and  place  them  an  inch  apart  in  pans  of  similar  compost.  Still 
afford  them  the  same  temperature  and  moisture. 
Cocoa-nut  fibre  affords  a  suitable  medium  for  rendering  a  moist 
base  on  which  to  place  the  pots  and  pans.  It  is  easily  damped,  and 
readily  allow*  heat  to  pass  through  it  ;  but  any  of  this  material  in 
contact  with  the  hot-water  pipes  soon  dries.  In  a  measure  it  then 
prevents  the  heat  ascending,  so  this  portion  must  be  »pecially 
iooked  to. 
Very  light  sprinklings  of  water  are  necessary  when  the  seedlings 
are  first  spaced  out  ;  but  as  they  grow  more  may  be  given  with 
good  result*,  also  light  and  air  in  proportion,  following  with  an 
introduction  to  a  cooler  temperature  preparatory  to  potting  into 
small  pots,  shifting  on  as  required  until  a  flowering  size  is  reached. 
Good  plants  from  seed  raised  now  may  be  had  in  flower  in  autumn, 
but  any  tuber*  that  do  not  attain  strength  and  size  enough  to  flower 
this  season  make  fine  plants  the  following  year. — E.  D.  S. 
CHEMISTRY  IN  THE  GARDEN. 
( Continued  from  page  76.) 
Sulphur  (symbol  S). — This  element  is  a  brittle,  solid  substance, 
of  a  lemon  yellow  colour.  It  is  found  in  a  free  state  in  nature, 
and  also  in  combination,  in  a  variety  of  forms,  with  other  elements. 
Sulphur  i*  found  in  a  free  state  in  many  parts  of  the  world,  parti¬ 
cularly  in  those  districts  where  volcanic  action  is  going  on. 
Sulphur  combines  chemically  with  oxygen  in  several  different 
proportions,  but  the  following  is  the  only  form  we  need  consider  : — 
One  part  of  sulphur  united  with  three  parts  of  oxygen.  This 
substance  is  called  sulphur  trioxide  (SOg),  and  when  combined 
with  one  part  of  water  form*  *ulphuric  acid  (H2S04).  This  acid 
combines  readily  with  alkaline  and  other  bases  (e  g ,  potash, 
ammonia,  lime,  or  iron)  to  form  sulphates,  good  examples  being 
sulphates  of  potash,  ammonia,  lime,  and  iron  ;  and  it  is  from  one 
or  the  other  of  these  *ub»tances  that  plants  obtain  their  sulphur. 
Phosphorus  (symbol  P)  — This  element  is  never  found  in 
nature  in  a  free  »tate.  It  can  be  prepared,  however,  from  com¬ 
pounds  containing  it,  when  it  has  the  appearance  of  a  colourless 
transparent  solid  substance.  Combined  with  other  elements 
phosphorus  is  one  of  the  most  widely  diffused  of,  all  the  elements. 
Phosphorus  combines  readily  with  oxygen  and  hydrogen  to 
form  phosphoric  acid  (H6P208).  From  its  chemical  formula  we 
see  that  one  part  of  this  acid  consists  of  six  part*  of  hydrogen, 
two  parts  of  phosphorus,  and  eight  parts  of  oxygen.  The  acid 
combines  with  bases  like  lime,  magnesia,  and  iron  to  form  phosphates 
of  lime,  magnesia,  and  iron  ;  and  these  are  the  forms  in  which  it 
exists  in  soils.  The  amount  of  phosphoric  acid  in  many  soils  is 
very  small,  and  even  the  most  fertile  do  not  contain  very  large 
quantities.  Phosphorus  is  taken  from  the  soil  by  plants,  princi¬ 
pally  in  the  form  of  soluble  phosphate  of  lime  ;  and  the  element 
is  found  in  them  chiefly  in  the  albuminoid*  and  seeds. 
Potassium  (symbol  K).— This  element  is  a  soft  white  metal 
slightly  tinged  with  pink.  It  is  never  found  in  a  free  state  in 
nature,  but  occurs  in  large  quantities  in  combination  with  other 
elements.  Potassium  unites  readily  with  oxygen  to  form  potash 
(K20),  and  with  oxygen  and  hydrogen  to  form  caustic  potash 
(KHO).  Potash  forms  one  of  the  alkaline  bases,  and  will  therefore 
combine  with  acids  to  form  salts.  The  potash  salts  are  found 
very  widely  diffused  in  nature,  some  of  them  (silicates  and  nitrate 
of  potash)  being  present  in  soils,  while  others  occur  (sulphate  and 
chloride  of  potash)  in  some  saline  deposits  and  in  sea  water. 
Potash  is  found  in  plants  in  combination  with  organic  acids. 
Its  use  in  the  plant  seems  to  be  to  help  in  the  formation  of  starch, 
and  it  is  absorbed  from  the  *oil  chiefly  in  the  form  of  sulphate  and 
nitrate  of  potash. 
Magnesium  (symbol  Mg). — This  element  is  a  silver-white  metal, 
never  found  in  nature  in  a  free  state,  but  always  in  combination 
with  other  element*.  If  magnesium  wire  be  strongly  heated  it 
takes  fire  and  burns,  emitting  a  brilliant  white  light,  and  falls 
down  as  a  white  powder.  This  powder  is  magnesia  (MgO),  an 
oxide  of  magnesium,  and  is  formed  by  the  chemical  union  of 
oxygen  gas  from  the  atmosphere  with  the  metal.  Magnesium  is 
found  in  nature  principally  in  combination  with  carbonic  acid,  as 
carbonate  of  magnesia,  but  it  also  occurs  to  a  lesser  extent  as 
Bilicate,  nitrate,  chloride,  and  sulphate  of  magnesia.  Plants  do  not 
require  a  very  large  amount  of  this  element  for  their  development, 
and  all  they  need  of  it  is  absorbed  from  the  soil  either  as  nitrate, 
sulf  hate,  or  chloride  of  magnesia. 
Calcium  (symbol  Ca). — This  element  is  a  soft  yellowish  coloured 
metal,  never  found  in  nature  in  a  free  state.  When  one  part  of 
calcium  unites  with  one  part  of  oxygen  it  forms  the  substance 
known  as  lime  (CaO).  Lime  combined  with  carbonic  acid  forms 
carbonate  of  lime  (CaCOs),  and  this  compound  occurs  in  Nature  to 
such  an  extent  as  to  form  no  less  than  one  sixth  of  the  rock  surface 
of  the  earth’s  crust. 
