There are currently no Ontario fertility recommendations for haskap. The following tables for nitrogen (N), phosphorus (P), potassium (K) and lime applications are guidelines only and are provided for reference based on similar common crops and published research on haskap in other jurisdictions (note: lime, phosphorus and potassium should always be applied according to a soil test).
Apply fertilizer in split applications starting just prior to bud break continuing to mid-July or at the end of fruiting with no more than 25 kg N/ha in any one application. Refer to Table 1 for season total nitrogen application guidelines for haskaps based on plant density and age.
Do not exceed 85 kg of actual nitrogen per ha per season regardless of number of plants per ha. The following are approximate values for low and high density plantings. For densities in between these values, use an intermediate rate. The exact amount of nitrogen to apply is a function of soil nitrogen level, cultivar, soil moisture, etc.
Phosphorus and Potassium:
In Canada, haskap is grown in a range of soil pH from 5.5 – 8.0. However, as with most horticultural crops, a pH range of 6.0 and above is typically suitable for plant growth. Ground limestone is traditionally used to correct soil acidity and is easiest to apply prior to crop establishment. In the case of perennial crops it can be difficult to incorporate large amounts of limestone after crop establishment. Applying and incorporating split applications of total recommended lime over multiple years will help distribute the lime more uniformly over a pre-existing planting and make it easier when working around perennial crops such as haskap. Soil pH and buffer pH will be provided on your soil test. The soil pH value indicates the current pH status of the soil. If the soil pH is lower than optimum, the buffer pH value is used to calculate lime requirements according to Table 4. Note: Full effects of lime may not be realized for up to three years after application.