You don’t need a farm to feed yourself; heck, you don’t even need soil! One of my TAFE teachers told us a story about how his grandfather in Holland kept his whole street alive during WWII by feeding them from a vegie patch he created on a vacant plot of land. If you’ve seen the houses in Holland, you’ll know that this plot could not have been very big. This is a heartening tale, as it means that as fruit and veg growers we’ll be right during WWIII, and that you can get a lot of food from a very small space. In fact, you can do very well even if your garden is just concrete that’s painted green. All you need are some containers, potting mix and a judicious choice of fruit and veg to grow. If you set it up right, you’ll soon have a continuous harvest going, enough to make you self-sufficient – well, as far as fruit and veg are concerned, anyway; Amish levels of self-sufficiency require a couple more articles to achieve. The only reason you’ll need to go to the greengrocer is to stick your tongue out and say nya-nya-nya-nya-nya.
What can I grow?
There are a few key attributes to look for in a prospective edible plant that make it suitable for self-sufficient container growing. One is size. As a rule of thumb, the plant’s full-grown habit shouldn’t exceed twice the pot’s height or 1.5 times the pot’s diameter. Don’t forget there are many dwarf varieties of popular plants, so you could even have fruit trees in larger pots. Harvest characteristics are obviously important too. Plants such as herbs and lettuces can have leaves picked when required, leaving the rest of the plant intact to continue growing and supplying all year round. Perennials like citrus and chillies supply year after year, but only during their fruiting season. Plants may fruit over long periods or require you to harvest all in one go. Either way, to extend the harvest period you need to plant a succession of crops so when one is spent, another one is coming hot on its heels. Popular container-grown vegies include tomatoes, lettuces, onions, beans, eggplants, capsicums, parsley, rosemary, basil and thyme, to name but a few. Vine vegies like cucumbers and pumpkins need more space and trellising for support, but there’s no reason you can’t grow them. As a general rule, use plants that tolerate transplanting or direct sowing. Often you’ll either be transplanting seedlings you buy from the nursery or seedlings you grew yourself from seed. Remember not to grow more than you can eat; do you really need seven varieties of lettuce?
What containers are best?
The best containers are free containers! Anything that won’t leak potting mix will do the trick; try old buckets, boots, golf bags, wooden boxes, terracotta (of course), old jugs, old appliances, hollow logs, old furniture, computer cases ... Just make sure you give repurposed containers a good clean, so you don’t end up eating unsavoury stowaway pathogens. Each container material has different properties you need to adjust for. Plastic can get hot enough in summer to kill plants, so it’s best avoided and recycled instead. Porous materials like wood or unglazed terracotta dry out more quickly than sealed materials like metal or glazed terracotta. If the pot is quick to dry, a heavier potting mix should be used that retains moisture for longer. Also, dark coloured materials will get hotter in the sun and also need a heavier mix. Pot shape also has an effect on the plants. Water tends to drain to the bottom of the container; if you have a tall pot, that water may drain too deep for your plant’s roots to reach. A heavier potting mix can help alleviate this. Ideally, choose a container whose overall depth doesn’t greatly exceed the root-ball depth. The shallower the container, the more available the water, and the coarser you should make your potting mix. Once you’ve chosen a container, you need to ensure it has adequate drainage. A number of large, fully formed holes – ie, they don’t have grills or other blockages – are best. If your pot only has one drainage hole, like many store-bought terracotta pots, you need to fill the bottom third with free-draining material like rocks or gravel.
What’s the right potting mix?
The wrong potting mix is ordinary garden soil – it’s simply too heavy and will suffocate and/or drown your plants. Commercial potting mixes are ideal. Ordinary mixes (look for the black ticks) are fine for crops that require frequent replacement. For plants that last a couple of seasons or more go for a premium mix (look for the red ticks), which will have added goodies like wetting agents (so water is retained better), fertilisers and nutrients. You can make your own organic growing medium from vermiculite or well-rotted compost. Top it up with one-third sand, for drainage, and one-third composted pine bark, for particle size. Also add any extra fertiliser your plant may need and a wetting agent, and mix in well. The fertiliser you use will be a mix of controlled-release fertiliser, the synthetic pellets, added prior to planting, and liquid fertilisers given during subsequent waterings. Coated controlled-release pellets can be sprinkled on the surface of the potting mix when it comes time for a fertiliser top up. Watering draws the nutrients down to the plant’s roots. You can also try natural controlled-release fertilisers like blood and bone, pulverised animal manures and compost.
Do pots need ongoing care?
Plants in pots require ongoing maintenance, probably more so than plants in the ground. Number one, they need more frequent watering as pots and potting mixes lose moisture content comparatively quickly. This is mitigated through use of wetting agents and mulching, use something coarse and natural. If you have a lot of pots, consider rigging up an automatic drip watering system. During summer you may need to water twice per day. Remember, always use clean, fresh water on edible plants; unless you really don’t like your family and would love to see them get sick. Hmmm, Christmas lunch for the mother-in-law with vegies I’ve grown especially ... Pots need fertiliser to be added regularly as plants are much like teenage boys – they eat and drink everything in sight but fail to replenish any of it. However, this continual fertilising leads to a build-up of salts in the mix, meaning the mix should be replaced or have the salts leached out. Potting mixes are designed to hold an optimum amount of air and water. If the level of your potting mix starts to lower, the mix is probably compacting and it’s time to re-pot. Keep an eye out for potting mix that is becoming hydrophobic, ie, it no longer holds water, which runs straight through it instead. It’s either time to add more wetting agent or to re-pot.
Words by Sean Cummins