This week all the horticulture students did work experience somewhere. I went to The Lettuce Company, a hydroponic lettuce grower just outside of Clyde.
It was a really fun week and I learnt a lot from Mark and his team. The greenhouses are huge and hold thousands and thousands of lettuces at all different stages of growth. They grow four different types of lettuce: green oak (the most popular), red oak, green frill and red frill.
The first task I was given was sleeving up lettuces to be sent to supermarkets. It’s pretty simple. Pull the lettuce out of the growing tray, pull off any undesirable leaves around the base and wiggle it into the sleeve. They get put into boxes of 10, sprayed with water to keep them crisp and stored in the chiller before being sent out.
All the water and nutrients the lettuce need flows through the growing trays and is recirculated. They use very little water compared to other growing operations.
I also found it interesting that they don’t heat the greenhouses in winter, they actually just heat the nutrients that flow through the roots. It does get down to about zero degrees in there and some lettuces will get a bit of frost damage.
When I was working there the temperature was around 32 degrees. Since it’s getting warmer now as summer approaches they are going to start working at 5am to miss the worst of the day’s heat. In winter lettuces take about 8 weeks to mature, but only 6 weeks in summer. The seeds we sowed on Tuesday will be harvested for Christmas.
One of the tasks I enjoyed most was putting out the seedlings that were ready to be separated into the grow trays. The seeds are sowed into grow dam – a felt like substance that sucks up moisture and stays wet.
You rip off each little block and place it into the grow tray hole.
Since it has been quite hot recently we had to spend a bit of time taking some seedlings out of the hydroponic system that had grown too fast. They will be stored in the chiller to slow them down and put back out when needed.
Timing is really important make sure the lettuces can be moved through the glasshouse as necessary, from seed to seedling, to ready to be harvested. As big as the greenhouses are there is limited space in each section so you don’t want all the seedlings at the same stage and nothing else in any other section.
It was great to go home at the end of each day feeling like I had achieved something and even had some lovely lettuce to show for my efforts 🙂
Last week’s weather: