Cole Crops - Fertility

Starter Solution

If no insecticide is being added to the planting water, use a starter solution high in nitrogen such as 20-20-20 at 1 kg /200 L and apply 0.2-0.3 L per plant. Under high temperatures or in dry sandy soils, use half the recommended rate (in the same volume of water) to reduce the risk of crop injury under these growing conditions.

Nitrogen

If manure is applied or legume sod is plowed down, reduce the nitrogen 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 recommeded preplant nitrogen with all the required potash and potassium. Side-dress the remaining nitrogen approximately 3 weeks after field setting. See Table 9-23, Cole Crop Nitrogen Recommendations.

Table 9-23. Cole Crop Nitrogen Recommendations

Phosphorus

Soil tests are required to determine phosphorus requirements. Where the soil test values are 61 mg P per L soil (ppm) or higher, cole crops 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, cole crops 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.

Micronutrients

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

Boron Deficiency

Boron deficiency has been shown to cause hollow stem in broccoli, but not all hollow stem is caused by boron deficiency. Use caution when applying boron. This nutrient can built to toxic levels quite quickly, harming rotational crops. See the section Boron, on page 17, and Table 1-13, Application Rates for Magnesium, Calcium and Micronutrients, on page 16.

Molybdenum Deficiency

Molybdenum deficiency causes whiptail in cauliflower, broccoli and Brussels sprouts. See the section Molybdenum, on page 19, 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 can be useful 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 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.

See Table 9-24, Cole Crop Nutrient Sufficiency Ranges, on page 97. Only use sufficiency ranges as a reference and a guideline. Plant analysis does not replace soil testing, or a sound soil fertility program.

For more information, see the section Plant Analysis, on page 3.

Table 9-24. Cole Crop 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.

Broccoli - Plant Part: Most recently mature leaf

Brussels Sprouts - Plant Part: Most recently mature leaf

Cabbage - Plant Part: Most recently mature leaf

Cabbage - Plant Part: Wrapper leaf

Cauliflower - Plant Part: Most recenlty mature leaf

Chinese Cabbage (heading) - Plant Part: Oldest undamaged leaf

Related Links

• Publication 363 - Vegetable Production Recommendations

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