The superior quality and good taste of blackberries is very important and hence the farmers must be extra careful concerning the moment and way of harvesting to preserve their products and maximize their profits.
Blackberry Yield per Hectare and Acre
Blackberry plants can be commercially productive from the 3rd until the 10-12 years after planting, with the lifespan to be extended when there is the availability of nutrients and water, pruning is performed, and the pressure for diseases and pests is low. Among the three types of blackberries, the semi-erect are the most productive, while the erect is the most widely cultivated globally. Under normal conditions, most modern blackberry varieties can yield at least 2 kg (4.5 lb) per plant and up to 9 kg (20 lb). The average yield of mature blackberries is 7-16 tones per hectare (5,700-13,000 lb/acre), but yields of 22 tons per hectare (20,000 lbs/acre) have also been reported in the U.S.
When and how to harvest blackberries?
Harvesting blackberries at the right time and using proper techniques is essential to ensure the best flavor, texture, and shelf life of the fruit. The time to harvest blackberries depends highly on the region's climate and the variety of cultivated blackberries. Blackberries are ready to be picked when they reach their peak ripeness, which varies depending on the cultivar and local climate. Generally, ripe blackberries are easily detached (without being squeezed) and are fully black with a slightly dull, non-shiny appearance, indicating optimal sugar content. Shiny blackberries tend to be less sweet and more acidic. Apart from these indications, a taste test to define the juiciness and sugar content of the fruits can help you.
The harvesting period of a variety may last between 3-5 weeks, depending on the weather and the production system. During this time, the farmer should collect the ripe blackberries every 2-4 days. You can harvest by hand-picking or with special harvesters. One worker can collect, on average, 11-13 lbs (5-6 kg) of Blackberries in one hour. Picking when the fruit is wet can promote faster decay and should be avoided. Workers need to handle the berries gently, using a slight upward or downward motion to detach them from the plant without squeezing. This preserves the integrity and firmness of the fruit. To prevent crushing, you can place the berries in shallow containers, ideally in a single layer, and avoid overloading them.
Mechanical harvest is performed only in blackberries that will be utilized for processing or freezing. Choose a sunny day early in the morning (cooler time of the day). Let them dry from the cane if they are still drenched with dew or rain. If there is a weather forecast and rain is expected, you can harvest the fruits a bit earlier (when they are fully colored but more strongly attached to the stem). This is important because the rain may dilute the flavor and lead to fruit rot.
How to store blackberries to protect their quality?
Depending on the next steps, such as freezing, long transportation, or direct selling, the farmer must choose an appropriate container to place the fruits in. Usually, to reduce labor and fruit damage, the blackberries are placed in the sale container during harvesting.
Blackberries, like Raspberries, start to rot in just 24-48 hours after harvest when left at room temperature. However, even if handled appropriately and stored in optimum conditions, they can last up to 7 days, though their flavor and texture are best immediately after picking. To preserve the quality and longevity of the harvested blackberries, you need to apply pre-cooling (forced air coolers 34-37 °F or 1-2.7 °C) directly after harvesting to remove the field heat and minimize losses due to insect infestation and diseases. For extended storage, the pre-cooled fruits should be placed at 32 °F (0 °C) and a relative humidity level of 90-95%. Blackberries should not be washed until just before consumption or processing, as excess moisture can accelerate spoilage.
References
- https://content.ces.ncsu.edu/blackberries-for-the-home-garden
- https://ag.missouristate.edu/assets/MtnGrv/B39GrowingBlackberriesinMissouri.pdf
- http://www.extension.uidaho.edu/publishing/pdf/BUL/BUL0812.pdf
- https://hortnews.extension.iastate.edu/2011/6-15/smallfruit.html
- https://extension.okstate.edu/fact-sheets/commercial-blackberry-production.html
- https://publications.iadb.org/publications/english/document/Are-the-Berries-Ripe-Export-Potential-for-Ecuadors-Blackberry-Production.pdf
- https://extension.oregonstate.edu/catalog/pub/ec-1303-growing-blackberries-your-home-garden
- https://aggie-horticulture.tamu.edu/fruit-nut/wp-content/uploads/sites/6/2015/04/blackberries_2015.pdf
Further reading
- Blackberry Nutritional Value and Health Benefits
- Blackberry vs Black Raspberry - Similarities and Differences
- Blackberry Plant Information - How to Identify Blackberries
- Site Selection, Soil Preparation, and Planting of Blackberries
- Blackberries Propagation and Pollination
- How to Prune and Train Blackberries
- Water Needs and Irrigation of Blackberries
- Nutrient Needs and Fertilization of Blackberries
- Blackberry Pests, Diseases and Weed Management
- Blackberry Yield, Harvest, and Storage