organic gardeners in cities with limited space, growing food in
containers is a solution, but its important to understand the
challenges, so you can get the best results. My blog this week talks
about some of the main challenges which relate to soil fertility,
plant selection, ideal containers and watering.
living soil is the number one criteria for a healthy and productive
organic garden. A garden that is connected to the ground can draw up
minerals from a long way below the surface, can attract creatures
that live in the soil such as worms, and can be sensitised to drawing
in more nutrients and life forces by other plants living in the soil
near the plants being grown. You can use crop rotation in garden beds
to also naturally improve soil fertility. With all these processes,
you should end up with continuously improving soil.
container growing, most of these natural processes are not available
to the gardener. So its vital to recognise that your soil in
containers will never be as good as soil in the ground, if it had the
same attention, and the soil in containers will not continuously
improve. Once you have come to that realisation, what can you do:
with a healthy soil mix in the container, not just commercial
potting mix. The ideal is for some of the soil mix to be well made
compost from your own composting process.
attempt to grow plants that need high soil fertility
organic liquid fertiliser to the soil more regularly then you would
in a garden bed. You can make some of your own liquid fertiliser by
growing stinging nettle and comfrey.
the end of each year remove the soil from the container and replace
with a new soil mix that has compost. Don't dispose of your old
soil, use it in your compost process with plant, vegetable scraps
and some animal manure to add life back into the soil.
you choose to grow fruit trees and perennial herbs in containers,
removing the soil each year will be challenging, especially for fruit
trees which have a big root mass. Removing soil when your annual
vegetable crops are finished each year will be quite easy.
can grow vegetables, herbs and fruit trees in containers. With your
plant selection, apply the following guidelines:
plants with a high yield per space, ideally plants that like growing
on a climbing frame
plant that are easy to grow and do not require high soil fertility
plants that do not take up too much space
plant in season for your location
Containers can be made
from clay, ceramic, plastic, wood or metal. Clay and wood containers
tend to breath more than the other materials and allow better
transpiration of water, reducing the potential for water-logging.
Denser container material will hold heat longer which helps seed
The ideal container
size depends on what you intend to grow. Here are some tips:
trees with a large root mass will need much bigger container than
herbs or vegetables.
and small leavy plants with a shallow root mass only require small
especially root vegetables, require a reasonable depth of soil and
will demand large pots
select pots which are so large that they are too heavy to move. Once
of the key benefits of container growing is that you can move pots
around to make the most of the sun or protect them from the cold.
should have a layer of gravel at the bottom of the container and a
drainage hole. Sit the pot on a material that enables the water to
drain out properly. Maintaining ideal water conditions in container
growing is quite a challenge. The soil mixture in a container can dry
out quickly, compared to a garden bed which can access water from a
long way below the surface. Conversely, the soil in the container can
easily become water-logged, so over watering is also a common
problem. Its OK to let the surface soil of the container be a little
dry, test below the surface with your finger to feel moisture levels.
Gardener subscriber site can help you with container growing as it
Author Peter Kearney –