Rental Permaculture: Growing in Pots

If you, like many people around the world, live in a rental property, you may have discarded the idea of growing your own food because you don’t want to invest time, energy and money into a garden that you’ll eventually leave behind.

Whilst it’s great to improve the soil wherever you live as part of being an earth steward, it’s naive the think that it’s always going to be practical to do so. And with the rental market (in Australia at least) being the fickle beast that it is, sometimes tenancies are so uncertain that you may not even be around to see something you planted produce a yield.

Enter: growing in pots.

What makes pots so great?

Growing in pots makes a lot of sense when you’re renting, because obviously you can take your garden with you whenever you have to move, but there are a heap of other good reasons to grow in pots too. Here are a few:

  • Pots are often available for free (or very cheap) on hard-rubbish piles or Buy, Swap, Sell groups online.
  • You can upcycle and repurpose lots of different items into growing ‘pots’: olive oil tins, buckets, bowls, wheelbarrows, polystyrene boxes, even sinks and bathtubs (although they’d be pretty heavy to have to move!).
  • Pots are easy to move around, which means you can make use of different microclimates around the garden throughout the year as seasons change.
  • If a plant suffers disease or pest infestations, it’s easy to shuffle it off to a quarantine area away from other plants.
  • Invasive plants like mint, potatoes and Jerusalem artichokes can easily be kept in check when grown in pots.
  • It’s significantly cheaper to fill pots than it is raised garden beds.
  • You can cater for different plants’ nutritional needs easily with pots, by tweaking the growing medium you fill each one with, and which fertilisers or supplements you add (eg pine needles and coffee grounds to create more acidic soil for blueberries)
  • Pots can be positioned to accomodate for mobility diversity.

Feel the heat

The one major drawback to planting in pots is that they’re prone to drying out in summer, so you have to stay on top of watering them. This happens because they have a greater ‘surface area to volume ratio’, which essentially just means the soil around your potted plants’ roots has more area exposed to the elements than plants living in the ground (which only has the top surface exposed).

Plants living in the ground have the ability to send their roots deeper into the cool, damp earth further underground, but potted plants don’t have that luxury. Because roots generally grow outward from a central point, it’s the newest, most tender root growth that’s closest to the exposed sides of potted plants. So in summer, when the sun hits the sides of the pot, it’ll be the young roots around the edges that suffer the most. They’ll also cop the reflected and radiated heat from the ground that they’re sitting on: if that’s tiles or concrete, it can get pretty toasty!

Add to this that a large number of pots are either black or dark green, both of which are colours that absorb lots of heat from sunlight, and you’ve got a potential situation where plants would never stand a chance!

Stick together

The way we tackle these issues is to group our pots tightly together, to mulch heavily, and to provide shade and shelter on hot days.

Grouping pots together drastically reduces the amount of surfaces being exposed to the elements, and essentially creates a growing environment that’s very similar to a more traditional, larger growing bed. The plants on the outside of the huddle are exposed, but at least a quarter to half of their surfaces are protected. A bit like the way Emperor penguins shuffle around in enormous circles during storms so no one of them is exposed to the freezing conditions at the edge of the group, you can move your pots around each season to accomodate for the different types of plant you’re growing.

We’ve also had success using thick textiles (a folded old towel or blanket, hessian sacking, and more recently some wool batting that’s used for food packaging by some sustainable companies these days) wrapped around the exposed surfaces of the pots on the outside of our groups. It looks a bit funny, and you wouldn’t want to do it with your good towels (they’ll likely break down over a year or two outside), but it’s a small, simple solution that seems to work well.

Size is everything

When growing in pots, and especially if you’re a renter, it’s important to carefully consider the size of pots you use. As a general rule (although it’s definitely not true in all cases), the root system of most plants is at *least* as large as the plant structure above ground. By that rationale, the bigger the plant, the bigger the pot.

When you’re growing fruit trees – which is entirely possible in a potted rental permaculture garden – this obviously means you need decent sized pots. But it’s also important to consider the logistics of moving your potted plants: there’s no point planting a olive tree in a wine barrel pot unless you know someone with a winch to help you transport that whopper when your lease is up!

We stick to 50cm square pots for our fruit trees, as it’s a size we feel comfortable lifting on and off of trailers. The square shape is economical too, as it allows us to maximise trailer space on moving day.

Because their root systems are limited to 50 x 50 x 60cm, our fruit trees start to suffer if we let them grow too big. So we prune them hard in winter so the canopy stays roughly the same size as the pot. It’s kind of like the art of bonsai, but for big plants. Around every 3-4 years, we take the trees out of their pots (in winter when they’re dormant) and check over the root system. If there are any diseased or damaged sections, we’ll cut them out, and when a tree looks rootbound, we give the root system a light prune and the canopy gets an extra hard pruning.

Aside from the issue of matching pots to plants so they’ve got enough soil to adequately nourish them, it’s also important to remember that the size of a pot directly affects the surface area to volume ratio. As we know, the greater the surface area, the more chance of drying out, so if you choose predominantly small pots to grow in, you’re effectively increasing the time and money you’ll need to spend on watering.

As well as having increased chance of drying out from exposure, small pots also have limited capacity for actually holding water compared to larger ones. Because of this, we avoid putting super ‘thirsty’ plants like capsicum, chillies, peas and lettuce in small pots even if their root systems aren’t that large.

Lastly, it’s good to have a mixture of pot sizes in your potted rental garden, because this allows you to more effectively group them tightly as mentioned earlier. If you only have large pots, especially if they’re round, it’s much harder to eliminate spaces between them, which increases exposure to the elements.

Get your fill

We mentioned earlier that it’s significantly cheaper to fill pots with growing medium than it is larger garden beds, and there’s a chance it’s even cheaper than you think. We see lots of people filling their pots with commercially produced potting mix, but that’s not just expensive, it’s also a bad investment.

Potting mix is essentially fine chip bark, sand, colouring and usually some added synthetic fertiliser and wetting agents. Not only is it costly to fill containers with potting mix, you’ll likely need to replace it in 6-12 months, as all those added nutrients will have either been used up or washed away in that time.

Rather than buying plastic bags of potting mix, we’ve been filling our pots with the tried and true No-Dig method for at least 10 years. Essentially it’s just a simple layering of peastraw, dried leaves, homemade compost and worm castings like a lasagne in each pot. The brilliant thing about no-dig gardening is that you’re actually *building* rich, biodynamic soil in situ, so unlike potting mix, no-dig soil becomes more nutritious for your plants over time rather than less.

We wrote an article for Milkwood Permaculture all about how to create No-Dig pots, so if you’re keen to have a go at saving some money while setting up your potted rental permaculture garden, head here for all the details.

Hopefully you’ve found this interesting and useful for getting into growing food in pots in a sustainable, frugal way. If you’re interested in Rental Permacukture, you might like to check out these other posts in the series:


Nanna Anna

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