Good post-harvest care of your fields, whether blueberries or raspberries, can have a positive effect on your yield and returns next year. The opposite is possible if you choose to do nothing. The buds for next year’s flowers are formed in a period roughly September through October. This is one of the most important times in the growth cycle of berry plants in terms of determining your production for next year. The plant begins to store nutrients for next year’s early season growth. Maximizing the number and nutritional content of the floral buds in this period is one of the best ways to ensure that your production for next year reaches its full potential.
Do not apply nitrogen from this point on! Excess N may prevent plants from becoming dormant properly. If they don’t, there is a higher risk to winter damage.
A good way to determine fall nutritional requirements, in blueberries at least, is to submit leaves for a tissue test.
Zinc and boron in particular must be at optimum levels in your plants.
Boron has many functions within the plant, including cell division, sugar transport, and fruit and seed development. It is the last item here that we are most concerned about at this time. It has been well documented that boron is essential for proper pollen tube development as well as the germination of the pollen itself. Making sure that the pollen has enough boron is essential for maximizing your harvest. Now, all of this action of germinating pollen and pollen tube development happens in the spring. So why is it important to spray boron during the summer/fall? Studies have shown that fall applied boron is able to be stored by the plants for use in the springtime while the flowers are open and pollination is happening. Increased yield has been demonstrated in highbush blueberries with fall applied boron. Boron deficient plants can also have a reduced number of floral and leaf buds developing in the summer/fall.
Zinc also has various functions within the plant. These include internode elongation as well as a role in production of key growth hormones and enzymes. Zinc also plays a role in the development of the fruit seeds. Therefore, it stands to reason the time of greatest demand for zinc would be in the early spring while the plants are undergoing aggressive growth. This has been demonstrated to be true by Oregon researchers. It has also been shown that the availability of zinc in the soil is greatly related to the soil temperature. Cold soils will inhibit the uptake of zinc by the plant. Since early spring is the time of highest plant demand, and also the time when it is hardest for the plant to take it up, it makes sense to foliar apply zinc at that time. While this is very true, however in the Fraser Valley many of the fields are inaccessible to spray equipment due to wet soil. The next best alternative is to do a fall/late summer application and let the plant store the zinc in the tissue to be used in the early spring.
Make sure any fall granular fertilizer applications contain both boron and zinc. All TerraLink fall blends do as a matter of course. Growers also typically apply micronutrients by foliar application. Foliage continues to grow throughout September, and leaf tissue will absorb foliar micronutrients. Contact us today to find the best products for your crops' needs.