Greenhouse Growing Techniques

Many growers are small, family-run partnerships that used to produce from older, timber framed glasshouses. However, these are fast disappearing as new housing subdivision spread to the rural/urban fringe. Those who remain have upgraded to either modern twin skin plastic houses or Dutch-style glasshouses.

Although it is not unusual for growers to have 0.5 - 1 hectare of greenhouses), some still grow outdoors. More than half the tomato growers in the Otaki and Horowhenua districts, for instance, produce from outdoor crops in summer and early autumn. Small outdoor crops are also still grown around Auckland & Christchurch, mainly as 'pick-your-own' crops.

Most growers use soil less media, planting into pumice or sawdust filled plastic bags or buckets, or in rock wool or cocopeat slabs. These are all hydroponic or semi-hydroponic systems. However, a small number of growers are (still) growing in the soil. Many heat their greenhouses solely for frost protection but most now heat their greenhouses for total environment control to achieve increased yield, a reduction in disease issues, and to maintain consistent quality.

Most growers are committed to year round production, and utilise bumble bees for pollination, CO2 injection to maintain ambient levels, as well as water treatment and other European technology. Many use a predator to control whitefly, and varying degrees of Integrated Pest Management (IPM) in their pest and disease programmes.

Although the average operation is relatively small in area, e.g. 3 – 10,000 square meters there are also a number of large growing operations, ranging from 1 or 2 hectares through to 5 or more hectares. Two operations comprise 20 hectares of glass each. Larger units may be jointly owned or have investor partners.