Growing Technique

Maarten and the team are consistent with their research and development of our soil preparation, bulb/corm treatment and growing techniques, for consistent quality and improvements.  Following are the basic processes for each of the flowers that Blokker currently follows.


Virus free Freesia corms are imported from Holland.  Blokker also uses its own corms that come from the bulb production areas outside.  Approximately 2 million corms are planted per year, for flowering in about 30-40 plantings.  Freesia corms undergo different temperature treatments during storage to be able to control dormancy, germination and temperature treatment in the soil after planting to be able to control flower length, timing and production.  The planting is completed by machine that also lays the heating and cooling pipes into the ground at the same time.  This ensures that the corms are planted close to the pipes to save energy.  After planting, a specially designed machine spreads pine shavings over the bed, compacting the seed bed, insulating the soil; saving on heating and cooling costs and helping in the germination process again.  The total length of the freesia crop from planting to digging lasts about 24 weeks, and each corm will produce 2-3 stems.


Iris bulbs are sourced from The Netherlands, New Zealand and Tasmania to ensure there is fresh planting stock year-round. Upon arrival they are stored in a 30°C room to keep the dormant. Every week, one planting worth of bulbs gets taken out and gets roughly 4 weeks of treatment at different temperatures, depending on the season. This ensures a good strike rate and makes it possible to determine leaf- and flower length. The bulbs are than planted by hand by the team.

About 5 weeks after planting, when the plants are about 20 cm tall, a quarantine inspection is done.  4 weeks later, flower picking has usually started, 3 times a day for every day of the week. The crop is usually totally picked and dug out within 3 months of the crop being planted.  Blokker plants about 2 million iris bulbs per year, with one bulb producing only one bloom all flowering between October and May.


Blokker imports seed and tissue culture from various suppliers.  The seed and tissue culture is then planted to grow into corms.  The corms harvested from this crop are planted outdoors for development again as it is during this phase that the tubers multiply and grow into the correct size for flower production. The corms for flower production are then treated and planted in both the glasshouses and outside for spring and summer flowers. There also are corm production areas outside for mail order and potted colour customers.

The soil preparation is just as important as the quality of the bulbs.  The first stage of planting is ripping the soil.  Sawdust gets added as a soil conditioner and then the sterilization of the soil begins.  Soil sterilization used to be done with Methyl Bromide.  Long before this was banned Blokker already purchased a 3 MW steam boiler to be able to pasteurize the soil, in a safer, more effective and environmental friendly way.  The actual steaming process of one planting takes approximately 8 hours and is completed by the soil preparation team. The steaming itself needs to be completed a minimum of 1 week before planting, to allow the soil to cool down sufficiently for planting.

Irrigation on the outside paddocks is overhead sprinkler only, usually through the night, to ensure minimum evaporation and maximum soakage.  Indoor irrigation gets done via overhead sprinklers and drip irrigation; fogging is used for cooling.This ensures an even temperature throughout and is controlled automatically by the climate computer.  Blokker fertigates with the drip system and tests the soil on a weekly bases to ensure the plants use up all the fertiliser and water.