LATE SUMMER FERTILIZATION OF STRAWBERRIES 



William J . Lord 

 Department of Plant and Soil Sciences 



In Massachusetts, the June-bearing varieties o£ strawberries 

 initiate their flower buds in the fall. If conditions are favor- 

 able, many varieties produce several flower buds in each strawberry 

 crown and consequently produce several inflorescences per plant. 

 The extent of flower bud development seems to be influenced by the 

 supply of available nutrients, particularly nitrogen. 



A number of experiments have indicated an advantage of build- 

 ing up the nitrogen supply in the fall from the standpoint of 

 increased flower bud formation. However, factors such as earliness 

 of runner plant rooting, quality of plants, soil moisture, and 

 pest and weed control may have more effect on plant productivity 

 than the fertilizer applications. 



A recent study in Minnesota showed that nutrition can affect 

 winter-hardiness of 'Redcoat' strawberry plants. In this study 

 'Redcoat' strawberry plants deficient in nitrates, phosphorous, 

 and potassium received fertilizer treatments in late-August. Arti- 

 ficial freezing tests were conducted on the plants at the onset of 

 their acclimation to cold weather, and in mid-winter with fully 

 hardened plants. Plants fertilized with a complete fertilizer of 

 1:1:1; 2:2:2, 1:1:2, or 1:2:1 ratio made better recovery from the 

 early and m.id- season artificial freezing tests than the non- 

 fertilized plants and those that received a fertilizer with a 

 1:0:0, 2:0:0 or 1:1:4 ratio. 



Winter injury to strawberry plants is of frequent occurrence 

 in Massachusetts, thus it may be worthwhile to fall fertilize* with 

 a complete fertilizer rather than one containing nitrogen alone, 

 as has been suggested in the past if the plants lack vigor. We 

 suggest applying a complete fertilizer (1:1:1, 1:1:2, or 1:2:1 

 ratio) at the rate of 30 pounds of actual nitrogen per acre. 



A broadcast application of fertilizer at that time may damage 

 the foliage unless precautions are taken. Apply on a clear day 

 of low humidity and shake off any fertilizer adhering to the 

 leaves, (a switch made from brush is convenient) or apply during 

 a rain, to avoid burning of the foliage. 



About late August. 



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