Lettuce, Endive and Parsley- Fertility

Nitrogen

If manure is applied or legume sod is plowed down, reduce the nitrogen (N) application. See Table 1-8, Adjustment of Nitrogen Requirement Where Sod Containing Legumes Is Plowed Down, and Table 1-7, Average Amounts of Available Nutrients for Different Types of Manure, on page 9.

Broadcast and incorporate the recommended preplant nitrogen with the required potash and phosphate. On mineral soils, side-dress the remaining nitrogen 3 weeks after transplanting or thinning the crop. See Table 9-43, Lettuce Nitrogen Recommendations.

Table 9-43. Lettuce Nitrogen Recommendations

Phosphorus

Test the soil to determine phosphorus requirements. Where the soil test values are 61 mg P per L soil (ppm) or higher, lettuce crops on both muck and mineral soils are unlikely to respond to additional phosphate applications. For soils testing lower than 61 mg P per L (ppm), see Table 1-10, Phosphorus Requirements: Vegetables on Mineral Soils, on page 12, or Table 1-11, Phosphorus and Potassium Requirements: Vegetables on Muck Soils, on page 13.

Potassium

Test the soil to determine potassium requirements. Where the soil test values are 181 mg K per L soil (ppm) or higher, lettuce crops on both muck and mineral soils are unlikely to respond to additional potash applications. For soils testing lower than 181 mg K per L (ppm), see Table 1-12, Potassium Requirements: Vegetables on Mineral Soils, on page 14, or Table 1-11, Phosphorus and Potassium Requirements: Vegetables on Muck Soils, on page 13.

Secondary and Micronutrients

Crops vary greatly in their response to micronutrient fertilizers. For complete information, see the section Micronutrients, on page 16.

Copper

Copper (Cu) deficiency may show up on organic (peat and muck) soils. Mix copper with the fertilizer and apply at 14-29 kg Cu/ha (12.5-25 lb/ac) on newly cultivated muck. Subsequent applications may be made every 2 or 3 years at about one-third the rate recommended for new muck. See the section Copper, on page 18, and Table 1-13, Application Rates for Magnesium, Calcium and Micronutrients, on page 16.

Manganese

Manganese-deficient lettuce shows marked yellowing between the veins, which remain dark green. Manganese deficiency usually shows up on slightly acid or alkaline muck, peat and dark-coloured sandy soils. Soil application is not recommended for manganese because of the large amounts required. If a deficiency is identified, apply foliar manganese sprays starting after thinning or transplanting. For more information, see the section Manganese, on page 18, and Table 1-13, Application Rates for Magnesium, Calcium and Micronutrients, on page 16.

Calcium

Under hot, dry conditions, lettuce may benefit from calcium to prevent tipburn or blackheart symptoms. See the section Calcium, on page 15, and Table 1-13, Application Rates for Magnesium, Calcium and Micronutrients, on page 16.

Plant Analysis

When used in conjunction with a soil analysis, plant analysis is a useful tool for diagnosing crop problems or for evaluating a fertilizer program. The objective of a good fertilizer program is to maintain tissue nutrient concentrations on the lower side of the sufficiency range. Attempting to bring the nutrient analysis up to the higher end of the range could possibly result in over-fertilization and may not be economical. For more information, see the section Plant Analysis, on page 3.

Only use sufficiency ranges as a reference and a guideline. Plant analysis does not replace soil testing, or a sound soil fertility program. See Table 9-44, Lettuce and Endive Nutrient Sufficiency Ranges.

Table 9-44. Lettuce and Endive Nutrient Sufficiency Ranges

Adapted from Maynard, D.N., and G.J. Hochmuth. 1997. Knott's Handbook for Vegetable Growers, 4^th Edition. John Wiley & Sons, Inc. New York

Endive - Plant Part: Oldest undamaged leaf