PLANTING POTATOES 243 



Seed potatoes to receive certification must be free from the pests 

 and diseases specified in the law cited. 



Unless the seed potatoes are old and show active eyes, they 

 should be exposed to the light for about two weeks to advance ger- 

 mination. This is especially the case when the tubers of an early crop 

 are used for later planting the same season or when seed potatoes 

 are taken from cold storage. In that case, vitalize it by exposure 

 to half sunlight for two weeks or more and see that it is disposed 

 to sprout before planting. This is a rational treatment for all po- 

 tatoes which do not seem to be starting their eyes. In the fresh 

 seed it promotes maturity; in stored seed it determines viability. 

 Never mind if it greens the tuber that is no objection, though, of 

 course, one does not wish to blister or burn the skin by too much 

 direct sunshine. 



All proposed methods of seed-cutting have been tried in Cali- 

 fornia, and each has its advocates. When the soil and season favor, 

 excellent crops are grown from small potatoes used as seed, but 

 commendation of small potatoes for seed does not include the 

 "nuts," which are usually immature, without well developed eyes, 

 etc. Besides, these "nuts" do not have bulk of starch sufficient to 

 strongly start new plants. The smaller potatoes are good for seed 

 providing they have bulk enough and are well matured. They are 

 preferred in planting for second crop in the interior because large 

 potatoes will rot if cut and have too many eyes if not cut. Some 

 growers grow their own seed small purposely by crowding the 

 plants, culture otherwise being as it should be, so that the small 

 potatoes are from good stock and not runts. Generally the selected 

 fair-sized, merchantable potatoes, cut into quarters lengthwise, pro- 

 duce best results. Cutting to single eyes is not a good commercial 

 practice. In certain prize contests, with a maximum of favorable 

 conditions in soil and fertilizing and cultivation, the greatest yields 

 have sometimes been had by single-eye planting. Under ordinary 

 conditions the thriftiest plants come from eyes which started with 

 a good amount of the plant-food stored in the tuber therefore 

 cutting into two-ounce pieces is commended by some, while most 

 planters do not cut at all, unless the seed tubers are above average 

 size. 



When things are otherwise favorable, the size of the crop 

 usually bears relation to the weight of the seed used to the acre 

 therefore a good weight of seed is a good investment. 



There is no advantage in cutting long before planting; there 

 is more danger of injury by fermentation. 



Distance between pieces in the furrow depends upon the ten- 

 dency of the potatoes to grow too large. This is often corrected 

 by dropping more thickly. The range is from twelve to twenty 

 inches usually. It is usual to use from ten to fifteen sacks of po- 

 tatoes in planting an acre sometimes even more seed is used. 



