THE JOURNAL 



OF THE 



BOARD OF AGRICULTURE 



Vol XVL No. 3- 



JUNE, 1909. 



THE "GREENING" OF POTATOES. 



George Massee, 



Assistant Keeper-, Royal Botanic Gardens, Kew. 



The "greening" of potatoes intended for "seed," which 

 is brought about by exposing the tubers to light for some 

 weeks before planting until the skin assumes a dark green 

 colour, is a practice that has been followed for many years, 

 and is generally admitted to be productive of good results, 

 although it is still too frequently neglected. The opinion 

 of growers who consistently follow this practice is that the 

 haulm or "top" is much more sturdy and robust than when 

 the seed is not "greened," and this, as would naturally be 

 expected, results in a better crop. Certain experiments have 

 been conducted at Kew for the purpose of ascertaining in 

 what particular manner "greening" proves beneficial. 



Experiment No. i . — Two batches, each consisting of twelve 

 tubers of the variety called " Up-to-Date," and each batch 

 having exactly the same weight, viz., i lb. 8 oz., were 

 placed singly on a shelf in a room where they were exposed 

 to a good light. The experiment commenced on August 25th, 

 six days after the tubers were lifted. One batch was covered 

 with opaque black paper, the other batch was left exposed to 

 light. The sprouts were constantly removed on their earliest 

 appearance, and all the potatoes were turned over once a 

 week. The experiment terminated on March 25th. On 

 weighing, it was found that the batch that had been 

 covered with black paper had lost exactly 3 J oz. in 

 weight, whereas the batch that had been exposed to light, 



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