10 



The purpose of these experiments was to ascertain the opti- 

 mum amount of water necessary to hold the rot in check. The 

 plants in the first four series of pots (1 — i) were much inferior 

 to those in the last four series (6 — 9). In the first four series 

 the plants were more or less stunted and in the last four, which 

 contained more water, the plants had more foliage and more and 

 larger fruit, and appeared healthier. In the first series, in which 

 the water was less than 55%, there were 11 cases of blossom 

 end rot, while in the series in which the water exceeded this per- 

 centage there were eight cases of rot. The results of this single 

 experiment, however, are not conclusive, but they indicate that 

 the presence of a certain amount of water exerts an influence on 

 preventing the rot, and verify our own experiments to a certain 

 extent. However, many factors enter into a problem of this 

 nature, and a single experiment in pots was not on a large enough 

 scale to be conclusive. Moreover, top-watering is entirely dif- 

 ferent from sub-irrigation, whether in pots or in beds, as shown 

 by Selby's and our own experiments. 



For the control of blossom end rot it is necessary that the 

 soil contain the required amount of water, when the fruit is 

 setting, and during its early maturity. A pot might be abun- 

 dantly supplied with water at the surface of the soil in the 

 morning, and on a very dry day would dry out before the next 

 watering if the soil was of a loose texture. 



It is quite evident from the result of our experiments on the 

 blossom end rot of tomatoes that the presence of water in liberal 

 amount in the soil is of the greatest importance. Watering by 

 sub-irrigation is quite dififerent from surface watering, since in 

 the former method the water is most easily obtained by the roots. 

 The surface of the soil may be comparatively dry, and the lower 

 stratas well supplied with water in the sub-irrigation beds, while 

 quite the reverse often occurs in the top-watered beds. The 

 inexperienced gardener, when applying surface water, too often 

 has little conception of the conditions below the surface. The 

 roots of tomatoes, when not restricted in growth, will extend to 

 quite a depth in good loam, and when surface watered, it often 

 happens that the upper layers of soil get sufficient moisture, but 

 the lower stratas which are well filled with roots, remain com- 

 paratively dry. Then again, when water is supplied even liber- 

 ally to the soil there may be periods when the soil dries out very 

 rapidly, and the plant may sufifer from lack of water, as a result 

 of which the rot will often occur. 



In controlling the blossom end rot in the greenhouse great 

 care should be exercised as regards the percentage of moisture 

 in the air. It is not advisable to keep the air too dry, especially 

 during bright sunshine ; on the other hand, the air in the house 



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