108 PLANT GROWTH 



than is given to fighting them when they are allowed to grow 

 rampant until they are mature, have damaged other plants, 

 and have produced a crop of seeds for a new generation. 



There are many methods of controlling weeds, but in each 

 case it is easiest if we take advantage of a knowledge of the 

 weed's life history. Weeds that grow from seeds in the culti- 

 vated areas can be destroyed very easily and rapidly by 

 hoeing or raking when they are small seedlings. They have 

 a small root system and have not commenced to store food. 

 Most of them will die before the roots can become re-estab- 

 lished to absorb water. Hand pulling of annual weeds is 

 rapid and useful in small areas, but pull them while they are 

 small; when they are grown they have done their damage 

 and produced seeds for next year. Mature weeds take twice 

 the time, ten times the effort, and have a hundred times as 

 much material to destroy as young ones. 



Some of the weeds with root-stalks are most difficult to 

 eradicate. The plants may be entirely removed from a small 

 area or they may be starved by keeping the new growth 

 chopped off, or by using some other plant to smother them 

 out. Weed manuals give detailed advice for various species. 



Weeds in the lawn are more difficult to control than those 

 in the cultivated area. They are not easily seen as small 

 seedlings, and pulling after they have grown larger often 

 destroys several plants of grass. The weed control should 

 begin with the starting of the lawn. It is impossible to start 

 the lawn without weeds but many can be avoided with 

 thought. Sod may have undesirable grasses as well as many 

 other weeds, but it is possible to get reasonably good sod. 



Seed should be reasonably free from weed seed, but it is 

 impossible to buy seed that is weed free. It should be free 

 of the weeds that are considered to be the worst and are 

 therefore unlawful. 



A good lawn is the greatest help in fighting weeds, there- 

 fore, we should begin with the soil when we start the lawn. 



