There are many reasons people turn to container gardening. Perhaps you have no bare ground at your flat. Maybe, the landlord does not want you to dig up a lawn or disturb the ornamental plants growing in the beds. Maybe, like me, you move once a year or so and growing perennials would be a waste of time otherwise. Sometimes, like in the case of tomatoes, its your best bet to grow in containers and catch all the sun you can in the short growing season. Whatever your reasons its pretty simple to apply permaculture theory to container gardening.

Quick Jump to sections of this post:

• The container
• The plants
• Growing Tomatoes
• The soil
• Where to Place your container

The container:

Any container will work if you make sure there is enough drainage at the bottom. Some plants like wet soils, others moist still others like it on the dry side. Look it up once you've picked your plant. Help the soil drain by putting gravel or broken ceramic at the bottom. If it likes moist to wet soils, chuck some mulch or compost at the bottom. I prefer 20 liter buckets because that is as big as I can carry around. If you don't plan on moving the container the bigger the better (means more plants and bigger roots). If your container is a dark color, like black, you might want to paint it a lighter color unless you live in a cool climate. I have grown annuals in tires, but usually with access to soil underneath. Tires work well for my winter veggies, but my summer crops have suffered and bolted to seed on a few occasions. I like them for potatoes because they are stack able, but slugs also like to hide in them. I let weeds grow around them so they're not so hot in the hottest part of the summer (pretty short part of the Dunedin summer).

The plants:

What plants you choose depends on your preferences but also whether the container is a suitable size.  Perennials can have deep roots so you should pick one thats roots will fit in the container with some spare room. If you pick a larger plant like an apple tree, or bush like a fuchsia you will need to trim back the tops and the roots. How often you do that depends on how fast it grows in your climate. I get away with doing it once a year. If you pick smaller plants you won't have to trim them back as often. If you're growing an herb like mint, it will fill the whole of the container in a year or less. I take out half of it every year or six months depending on how warm the weather has been.

After you have chosen the perennial you can pick its companion plants. I always opt for white clover. None of my plants, even my apple that has shallow roots minds the clover in there.  I also plant small cloves of garlic and shallots I cant be bothered peeling into the containers. I pull them out before they go to seed (except for one or two so I can save some seeds), level it out with some compost and let the clover grow over the spot. Beans have bigger roots and only really do well in a few of my containers. ( It may have as much to do with the different soils as it does with its companions). I wouldn't put herbs in with them unless the container has a really wide diameter and make sure they are not shading the perennial while its young. Kitchen herbs can get big. Basil by itself warrants it's own container. Parsley can grow over a foot tall. I've seen those pots that have tons of little herbs growing together in one pot. Each plant is so small that it provides only one or two meals worth of herbs. Maybe its just me, but I use herbs in handfuls not tablespoons.  Make sure that you don't have more than one or two large rooted plants in the same container unless their roots are compatible shapes (eg. shallow root system in the same pot as a tap root. tomatoes and carrots). Showy flowering plants always improve a container. Clover, nasturtium or marigolds are good examples. These keep bees interested and cover the top of the container so weeds don't take over. Why not go for ones that are edible too?

Growing Tomatoes:

Many Dunedinites are forced to grow tomatoes in containers.  In fall, you can trim tomatoes down to one small leader at the base and bring it indoors(by a window. Don't let the plant get more than a foot tall and keep trimmed back until spring. Allow a few leaders to develop at the base 2/3 of the way through winter they grow really slowly over the winter). This way they start earlier the next season and unlike seedlings, don't waste time developing roots. The Brandywines that I grew that way live for 3 years before developing moldy leaf diseases of several varieties in the third winter. I started over with new plants this spring. Alternatively you could root some laterals from a plant that is doing well and allow their roots to develop over winter indoors. All cherry tomatoes from now on in my garden (not a long enough growing season here unless you have a warm green house). I only managed three or four tomatoes from each plant(trained as two leaders grown to four feet). The remaining fruit were mealy and bland from the cold autumn.

Click here for more on growing tomatoes

The Soil:

The soil you want depends entirely on what plants are going to grow in the container. Outdoor potting soil is best because its pest free, friable and usually has moisture retaining material in it. The drawback is its price tag, not to mention its hard to lug home (pedestrian). Personally, I use soil from the garden (it's free and just outside my door). I break it up with a shovel and discard the bugs, rocks and twigs.  I  mix in some compost and things that the plant might appreciate like sand, compost, leaf litter, etc.. Its important to fertilize them when you've had a few days of rain and to put compost on the top every so often (depending on how fast it breaks down). Every 2 or three months while its growing and a good heap before the plant lays dormant over the winter outside. Sometimes if it gets a bit full, I scoop out the older compost on top and put in fresh compost. When I trim back the roots I put fresh soil back into the pot around the root ball.

Where to Place Your Container:

Usually a sunny spot, sheltered from wind if you can. It really depends on the plant's needs, mostly its required hours of sunlight. Place it somewhere the rain can water it so you don't have to. You still need to water it if its been dry and hot for a few days and you can put it in a shady spot if your going away for a weekend in the summer.  Some of my plants come inside for the winter, the rest go somewhere out of the cold rain so they don't get moldy leaf diseases (especially mint). Some plants you can cut back and stick in the laundry room or under an overhang remembering to water as little as once a week until they come out of dormancy. (Depends on the plant and your climate). Really, it depends on the micro-climates you have around your yard and house. If you've got the right conditions for a certain plant, it may keep growing year round here. Look around, if you see a spot that mimics its natural niche put it there. I generally put them all in the sunniest spot in the summer and break them up in the winter depending on how sensitive they are to cold. If you live in a climate with a hot summer, putting them on a windswept sunny deck might burn leaves or dry a plant out in an afternoon.

You can bury pots if you prefer not to worry about them getting too hot and dry (and your landlord does not mind the bare patches on the lawn). Not being raised above the ground, their roots will not get as hot and not dry out as quickly. I like mine higher up so I don't have to bend down to notice things like weeds to pick out. It all sounds confusing but if you take a walk around your garden once a season it should be easy to find the best spot. If you want to make it  even easier, then write the plant's growing requirements on the container itself with a permanent marker. Note its light needs in hours per day, water needs as moist or dry, and what date it needs to be fertilized and trimmed back.