Spraying techniques are a major concern in the cultivation of potted plants. Two types of potted plant cultivation can be distinguished: crops on the ground/concrete floor (immobile culture), or crops on roll containers (mobile culture). Each type requires a different approach. The research was funded by the Product Board of Horticulture.
 
Pot plants on a mobile container (Calathea)
For pot plants in mobile containers (mobile culture), two spraybars with air support, were compared to a conventional spraybar. The spraybars with air support were the high pressure system from Arend-Sosef and the Pieton system from Van der Ende Pumps. The deposition of liquid on the untherside of the leaves increased with with both spraybars compared to the conventional spraybar. The coverage rates rose from 15 to 30% for large plants (50 cm high) to 60% for small plants (30 cm high). Spraying back and forth improved coverage by 7 to 14% for all methods compared to a single spraying. It should be noted that this was only performed with large plants. The spray was applied at an angle of 45 degrees during the trials, however this angle was too large for large plants. The droplets passed over the crop, rather than through it. Reduction of the angle to 35 and 25 degrees improved the deposition on the untherside of the leaves.

Pot on concrete floors (Banana Plants)
For potted plants on concrete floors (immobile culture) spraylances with two spray nozzles were added to a conventional spraybar. The crop was sprayed from below (spraying underneath) with the lances. The covered area on the untherside of the leaves was 0.5 to 5% with the conventional spraybar, whereas the coverage percentages achieved went up to 50% by spraying from below.

The sector is investing in this project via the Product Board for Horticulture.

This report is only available in Dutch: www.tuinbouw.nl

Source:
Unit: Wageningen UR Glastuinbouw - 6 Feb 2013