26 COMMON WEEDS 



temperature of 72 F. below freezing-point, still to 

 possess high germinating powers radish 92 per cent, 

 lettuce 85 per cent, turnip 96 per cent, &C. 1 All this 

 suggests that the length of life of many weed seeds may 

 be considerable. 



An interesting case showing the length of time seeds 

 will lie dormant in the soil and germinate when brought 

 to the surface occurred in connection with the Yeomanry 

 manoeuvres in 1901. A large rabbit warren on the 

 Oxfordshire hills was dug and levelled, no other soil 

 being used nor seeds of any kind sown. Yet in 1902 

 the whole surface produced a dense plant of yellow 

 Charlock. In the following year the Charlock died 

 down and was succeeded by a mass of White Campion 

 (Lychnis vespertind). The seeds of both plants must have 

 been buried in the earth for an unknown period of 

 years, and the disturbance of the soil enabled them to 

 germinate. 2 



The number of weed seeds which may be found in 

 the soil of a field is also extraordinary. Korsmo found 

 that in i square metre (1.19 square yard) of a fallow 

 field the seeds having power of germination, to a depth 

 of 25 centimetres (9.8 inches), were 10,332. This 

 was determined by three different weedings. In a 

 field intended for spring grain, the same crop having 

 been sown for four successive years, no less than 

 33,574 such weed seeds were found per square metre. 

 In a third field, which was fallowed, the seeds found 

 numbered 1,755. 



In a good garden soil which has been well cultivated 

 for at least three years, few weeds having been allowed 

 to shed their seed during that time, the author measured 

 off j square yard and removed all the seedling weeds 



1 The Times, 6th December 1904. 



2 Lawns, Sutton & Sons, p. 9. 



