Last autumn, I made myself a set of three greenhouse plastic row covers for my garden beds:
After trialling them this winter, I’ve decided they are definitely worth the hassle for a vegie garden in Melbourne. I don’t think greenhouses are essential – with careful planning you can have vegies to eat all year round in Melbourne. See my sidebar for how to really produce food in your backyard. If, like me, you have a fairly limited space for your vegies, then the greenhouse covers can help get a crop in and out of a bed quicker. I’m also hoping they’ll mean we get to eat summer vegies a little sooner, but that’s yet to be proven!
To make these greenhouses, I bought some “builder’s film” plastic from Bunnings. I think it cost about $40 for a roll large enough to do three tunnels plus the cover for my greenhouse shelves which you can see in the background.
I used plumbing pipe to create the hoops, and thin steel stakes 1m high to hold up the plumbing pipe. The reason the stakes are thin is so that the hoops will fit over them. Originally I pushed six stakes into my garden beds, put three hoops over the top of them, and then draped the cover over that. However, because my soil is so soft and fluffy, it wasn’t firm enough to hold the stakes. So I bought some little u-shaped pipe-holder brackets (sorry, I don’t know the proper name for them!) and nailed them onto the sides of my garden beds. Now the stakes slide neatly into them and remain properly upright. The stakes I originally bought from Bunnings (metal with plastic casing) started to break, and I discovered that “metal” actually meant “very very thin and flimsy metal tubing, no stronger than the plastic”. So don’t buy your stakes from Bunnings! I took them back and replaced them with steel reinforcement stakes that I got from a building supply shop.
The builder’s film I cut to size, and then sewed with a wide zigzag stitch on my sewing machine. I also sewed on a long plastic zip (don’t use a metal one – it’ll rust in the weather and you won’t be able to do it up), and then cut the plastic to create an opening where the zip is. Then I sewed some strips of fabric to the corners and middle of the bottoms of the greenhouse. These hang down to the ground, and I place bricks on them. If you don’t have raised beds, you can simply weigh down your greenhouse plastic with rocks.
As well as the faster growing crops, I’ve found the greenhouses very handy in terms of pest management. Our local possum has not bothered our vegies, when the chooks break into the garden, they don’t get in, and the cabbage moths haven’t either. So far this spring we’ve had a surprising lack of snails in these beds too – usually I need to be hunting for snails every night to stay on top of them. So they are definitely a winner for me. The drawbacks are that I must water manually, even if it’s been raining, and the garden doesn’t look as nice! Actually that’s quite a big drawback, because I love walking around my beautiful garden and admiring all the food. Now I walk around a plastic graveyard. Yuck. I fantasise about having a lovely glass structure over the entire vegie garden, which is somehow effortlessly dismantled over summer. If anyone knows how to do this, please do share!
In the meantime, for serious food growers, I reckon the greenhouse is a great addition. But if you just want to get started and grow some food, I think it’s low priority.