Commercial Growers/Hardening Off

Hi,

I'm just curious really, but how do commercial growers go about hardening off their plants? After all, they couldn't possibly carry thousands of plants in and out every day could they, or could they?

Josie

 

In climate controlled glasshouses or tunnels, for example in tunnels the sides will be raised, ends opened right up etc.

Steve...

 

I worked for a large nursery for a while and the young plants were started off in heated greenhouses and then moved to large polytunnels where all the sides could be opened up. Pretty much what Steve has said above.

 

I tend to think in most cases the high volume bedding plants are not hardened off when you buy them, that's why in a bad weather year like this they go backwards before moving forward.
Local nurseries that grow their own plants tend to take a bit more care, but I think you still need to use common sense, if it looks a bit soft and bloated, then its tender, and needs acclimatizing.

 

There's the coldframe route too; nurserymen may use that - so only have to carry once from Greenhouse to Coldframe, then open the "lights" on the coldframe each day - rather than cart in & out.

There were miles (well, I exaggerate a bit - but lots & LOTS) of coldframes when we visited Great Dixter last year.

 

Our local authority 5 span quarter acre polytunnel where I used to work had a roof vent and roll up sides of polythene and netting so hardening off was no problem, the glasshouse was not so easy as it only had top vents. The plants had to go out direct from there, no choice. We had cold frames too used for more hardy bedding such as Lobelia, Verbena and Petunias. Holding up or propping frames for watering was a pain!

The big commercial growers pass the hardening off problem to their buyers and they the big GCs keep them on trolleys and shelves, too warm and too little light making them less able to cope with their next move such as a window sill or cold greenhouse.