The reality of glasshouse growing

Still relatively new to glasshouse gardening, Justin has spent the past year learning as he goes. Here, he answers questions about his experience.

Q. What surprised you most once you started growing in your glasshouse?

The speed of growth was the first big surprise. I planted tomatoes and herbs straightaway and couldn’t believe how quickly everything took off. It definitely exceeded my expectations.
The other thing was the heat. It gets seriously hot. In summer it’s not uncommon for it to hit around 60°C inside, which was a bit of a shock.
In the cooler months though, it sits in the mid-20s, which is pretty much perfect for growing.

Q. How did your first summer go with your glasshouse?

Last summer was a bit of an experiment. I tried growing right through it and planted six different cherry tomato varieties. In the end, the ‘Tommy Toe’ was the only one that really handled the heat.
The first summer wasn’t a total failure, but about half the plants either died off or produced pretty average fruit. With temperatures regularly in the high 50s inside, it’s just a tough environment.
To manage the heat, I kept all the vents open and left the doors wide open pretty much 24/7.
The glasshouse does come with automatic vents… but I haven’t installed them yet!
I could have installed shadecloth over the glass roof to reduce the temperature, but I didn’t love how it would look.
Going forward, I won’t bother growing inside the glasshouse through peak summer, when I can grow everything outside anyway.

Q. How are you managing soil and watering?

I have a brick raised bed running along the southern side and shelving everywhere else. Over time I’d like to extend the raised bed around more of the greenhouse, as I’ve realised the shelving isn’t getting used as much as I thought it would.
Each season I remove most of the soil from the bed and add it to my compost, then refill with fresh compost and premium organic potting mix. Because I’m growing the same crops over and over, I prefer to start fresh rather than reusing the soil.
For irrigation, at the moment it’s still fairly basic. I plumbed water into the greenhouse during the build, but I haven’t fully set it up yet. The plan is to eventually install a misting system over the shelves and a dripper system into the raised bed.
For now, I’m hand watering most days. The soil definitely dries out quicker than it does in the open garden, so an automatic irrigation system is going to save my plants and my sanity!

To learn more about Justin O’Brien’s first year with his glasshouse, get a copy of Winter 2026 issue on sale at newsagents and selected supermarkets. You can also subscribe and get a copy delivered to your door!