7 Plant Analysis Sample latest mature, fully extended compound leaf. Sample weekly, beginning when first fruit is the size of a dime.
8 Talk Today History of tomato production in WNC Major nutrients discussedFertility recommendationsContributors — Dr. Greg Hoyt (NCSU) and Steve Dillon (NCDA&CS)
9 History of Tomatoes in Western NC Early 1950sStaked tomatoesResearch on fertility based on high rates of nitrogen and little to no irrigationUse of trellises began in late 1960sDrip irrigation began in the 1980s
26 Preplant Recommendations for Trellised Tomatoes Soil test.Apply P2O5, potassium, boron and lime as recommended.Apply up to 60 lb/acre of N preplant.
27 N & K Drip Fertility Recommendations Begin applying fertilizer when fruit is about the size of a dime.Apply (or equivalent) at a rate of 20–25 lb/acre/wk.Two weeks before first harvest, increase rate to 50 lb/acre/wk.Once 50% of crop is harvested, begin reducing rate.
28 N & K Fertilization in Drip-irrigation system Time of ApplicationN (lb/A)K (lb/A)Preplant40–70If deficient1 wk > 1st fruit set (~ 30 days > planting)3–4 / wk10–12 / wk *2 wks < harvest6–7 / wk20–25 / wkHalfway into harvest10–12 / wkApprox. season total90–130170–205* used to apply K and N in 3-to-1 ratio
29 Other Fertility Considerations Low P2O5 levels at harvest should not be a concern.Calcium levels should not be a concern with drip irrigation.Boron levels should be between 40–75 ppm throughout harvest.
30 Quality Fruit Begins with Careful Fertility Follow soil test recommendations.Use plant analysis for monitoring.Adequate water is essential.Monitor key elements boron and potassium.
31 Trellised Tomatoes and Drip Irrigation Bill YarboroughNCDA&CSAgronomic Division
32 For more information, browse the Agronomic Division Web site