Back in the 1990s, I heard a spoken word piece by Jello Biafra, formerly of the musical combo “Dead Kennedies”. His speech was heartfelt, and pointed out the political agenda behind the legal status of Cannabis sativa in the United States and most of the Western World, especially trading partners of the US. Much of this appears to be influenced by large chemical companies, patented processes, and nepotism. Once the most commonly grown fibre crop in the world, used in making everything from ship sails (“canvas” derives from the plant’s botanical name), and the best rope money could buy, to Levi’s jeans, and high quality paper; it is now barely cultivated (legally) at all. He at no point suggests that smoking copious bowls of the stuff will in any way improve anyone’s life, or help them achieve their goals. I tend to agree, unless those goals are knowing, by title, every episode of M*A*S*H. Or being able to accurately guess the prices on Antiques Roadshow before they come up on the screen.
But that, my green-thumbed friends, is not what this post is actually about. It was a cunning ruse to attract your attention, and now I can talk about the real topic: Growing plants in containers. I live in the inner city of Melbourne, and at some point, the block of land on which my house is situated had a Mediterranean Makeover. In other words, every bit of bare soil, with only two exceptions, is covered in concrete. This left me with a few options:
a. Move house
b. Get over it
c. Hire a jackhammer
d. Grow things anyway
For numerous reasons, the first option was not viable. I like where I live in general, and I won’t bore you with talk of “the market” at the moment. The second option I tried. I put in an inflatable pool instead. It didn’t satisfy my urge to grow things, as all it grew were millions of mosquito larvae. Sorry neighbours. The third option sounds a lot like really hard manual labour, to which I am certifiably allergic, not to mention being in breach of my lease.
So, I just grow things anyway. A garden in any urban setting is a relatively thin layer of soil that’s conditioned to grow selected plants. In many cases, it’s already a kind of container anyway, bordered by lawn, concrete or fencelines anyway, and with a bottom created by the harder, less fertilised, less aerated soil below. So growing things in a pot, or any other container, is not really all that different to growing in the ground, with a few notable exceptions. One thing it’s really good for is growing root crops, especially those where the top dies back at harvest, like garlic, for example. Just tip out the pot and sift through to find the goodies.
You can use anything as a container for growing plants, if it can hold “soil” (more accurately known as potting media), it can be used as a container to grow plants. Here’s where I start to qualify things. The best kind of containers are deep, with solid sides, and drainage at the bottom. The deeper the pot is, the more water it can hold, and the less often you will need to water it. By solid sides, I mean non-porous. Untreated terracotta pots are porous, which means they absorb water from the inside of the pot, and it evaporates off the outside surface, this means the pots can dry out more quickly. And drainage at the bottom allows for excess water to run off, because most plants don’t like waterlogged roots, and gravity generally makes water move in a downward direction. I do put saucers of some description under all my pots, though, as it helps indicate when they have been watered enough, and helps stop wasting any excess, as it will get drawn back up as plants use the water in the potting medium.
So, what is potting medium? It is any substance used to grow plants in containers that basically does what the soil does. It gives a physical framework for roots to grow in, it holds nutrients, it holds water, and it has large spaces in it for air to move through. Surprisingly enough, plant roots require air just as the shoots do, without it, they die, which can kill the whole plant, quite quickly in some cases. There is a balance between all these properties that form the ideal root environment for most plants, and a number of experiments that need to be carried out in order to assess various potting media. Luckily for non-boffins, there is an Australian Standard for potting mix. Actually there are two. Regular and Premium standard mixes are basically the same, the Premium containing a certain level of slow release fertiliser, while the Regular does not, though in both cases extra ingredients, such as “water saving” materials may be included. Look for the Standards Australia ticks on the bags, any other writing means very little, and price means even less!
So, what can you grow in containers? Anything. I have successfully grown Asparagus, Beans, Carrots, Dill, Eggplant, Fennel, Gherkins, Horseradish, Indian Bean Tree, Jicama, Kale, Lettuce, Marrow, Nasturtium, Onions, Parsnips, Queensland Blue Pumpkin (phew), Radishes, Sunflowers, Tomatoes, Um… Violets, Waxberry, X-tra hot chillies, Yam Daisies and Zebra Beans. Almost A-Z, and all edible. Some things, like the larger pumpkins, might struggle in really hot weather, but there’s no reason not to give it a go. Just find the biggest pot you can and start from there. Most of my pots have been discarded by others and I picked them up for nothing, even the big 50+ litre ones. You could also use other things, I have seen many an old bathtub or laundry trough recalled into active duty as a planter. Even old toilet pedestals get a run, sometimes. And the old black recycling tubs that councils used to give out were excellent. But I am not encouraging anyone to steal them.
Watering is a big issue. The bigger the pots, the less you will have to water, but the more you can grow in them, too. If you have lots of pots, it might be better to install a watering system, so you can water them all evenly with a turn of the tap, rather than carting a watering can back and forth, or using the hose (with trigger nozzle) to water them individually for as long as your patience lasts. Drip watering heads can be used, though they may create channeling in the pot, where water forms a course and runs straight through and out the bottom. This can happen anyway, especially if the pot dries out and the potting mix shrinks away from the side of the container. The best thing in that situation is to soak the whole pot in a bucket of water for a few hours, then water as normal the next day. There are also special downward spraying heads especially designed for containers, and these are best to use with a watering system, as they spread the application of water, and reduce the risk of channeling.
If you are really keen, and don’t mind clearing it up when you leave, you can even build garden beds on top of the concrete. Any kind of solid box shape will do, as long as it can handle the weather, and keeps your “soil” in place, it will do the job, a depth of half a metre of space for roots to grow should produce results. You can often spy old terracotta pipes turned on their end being enjoyed as sort of bottomless pots in landscapes all over the place. The thing is, don’t be discouraged by your concrete wasteland. There are ways to make it work for you. And the best part of container growing? You get to take it all when you leave. All the work you put in at one location, can still bring in returns if you move. So, come on renters, go for a walk, find some pots, and get growing.