Harvest practices for blueberries

Proper harvest of blueberries is essential for a successful supply chain. The performance of the harvesters is critical to delivering a good quality product. First of all, picking at the right maturity is important to develop a satisfactory final eating quality. Not only the harvest, but also further handling, such as grading, sorting and packaging, must be done carefully to avoid bruising and other damage to the product. The use of clean and suitable materials at all time from the harvest to the consumers contribute greatly to minimal losses.

Blueberries are picked at near to full ripe stage. Photo by Likee68/Shutterstock.com

Harvest of blueberries

If blueberries are harvested too early, they will not ripen and may not deliver satisfactory quality. On the other hand, blueberries that are harvested too late will be more susceptible diseases, dehydration and storage potential. Therefore, the end market must be taken into consideration when determining the harvest moment. For long distance transport, blueberries must be harvested at their highest storage potential. Once ripe, blueberries turn blue and develop their characteristic aroma, flavour and texture. Furthermore, in the final days before reaching harvest maturity, fruit size and juiciness increase strongly.

Attention points around harvest

  1. Blueberries are mature at 60-80 days after flowering. Photo from mutsu7211/Shutterstock.com

    Harvest maturity

    Depending on the variety and the environment, blueberries are picked 60 to 80 days after flowering. Similar to several other fruits, colour is often used to determine harvest time. Hand-picking of blueberries starts when 25% of the berries have turned blue and only berries that are nearly blue or blue berries are being picked. Additional harvests are required to harvest the entire crop. If harvesting is done mechanically, a threshold of 75% of blue berries is used. In total, there are 2 to 5 harvest rounds per field to insure a good maturity at harvest.
  2. Organic blueberry farm in the morning. Photo by M. Raota/Shutterstock.com

    Harvest frequency

    Harvests should take place every 3 to 9 days for a few weeks. With increased harvest frequency, a more homogeneous quality is observed. Also, average berry firmness tends to be higher, compared to berries picked at lower harvest frequency, i.e. with more days between harvests. As the turgidity, i.e. firmness due to water-pressure, is higher in the morning, this is usually the optimal time of harvest.
  3. Mechanical harvest of blueberries. Photo by TFoxFoto/Shutterstock.com

    Harvest method

    Hand picking is done for fresh blueberries destined for high-end markets. Mechanical harvesting is done for the processing industry or towards the end of the season. Hand picking offers the highest quality and the lowest occurrence of bruising or mechanical injury. Hand picking can also be done using a brush stock, although more damages may occur. It is faster than by hand but not as selective. Removal of the harvested leaves and damaged fruit is needed. Mechanical harvest is much faster than hand picking at a fraction of the labour, but blueberries show more mechanical damage
  4. Neatly filled and stacked boxes with berries in the field, ready for transport to the packhouse. Photo by Chizhevskaya Ekaterina/Shutterstock.com

    Placing in bins

    Blueberries must be carefully placed in the harvest bins and must not be overfilled. The pression of the stacked crates will damage the blueberries risking its marketing. Always put the crates in the shade to avoid building up of field heat until pick-up. The berries should be cooled down as soon as possible. After harvest, blueberries are moved to the packhouse for grading, packing, and cooling.
  5. Infected and discarded berries should be set apart. Photo by WUR

    Diseased and damaged fruit

    Diseased or damaged fruit should not end up in the lots intended for high-end market segments. Blueberries suitable for export are at least firm, free from decay and free from damage such as pathogens and bruises. A preliminary sorting in the field/greenhouse could be carried out by placing under-/overripe and damaged fruit in separate crates. Infected and discarded fruits should be removed from the field/greenhouse to reduce further infections. While sorting the blueberries, look for pests, diseases or disorders such as shrivelling, insect damage, bruising, Antracnose rot.
  6. Harvest material such as gloves are important to maintain good quality blueberries. Photo by WUR

    Materials

    The availability of good, clean and sufficient materials will facilitate harvest and product quality will benefit. Ensure that harvesting materials are sanitised before use. Harvesting material, such as gloves, buckets, harvest-brushes, should be well maintained and cleaned. Field crates should be clean, stackable and intact without sharp edges.