Gardening: Growing plants in containers

Growing plants in containers presents gardeners with endless opportunities, writes Gareth Carter.

Gareth Carter is the general manager of Springvale Garden Centre in Whanganui.

OPINION

Gardening is a pastime that can happen on a small or large scale.

Indoor plants and balcony plantings are the norm around the world for gardening in apartment-style living.

We still have mainly individual dwelling-type properties in NZ albeit often substantially smaller than our grandparents’ quarter-acre sections.

A smaller space still offers much opportunity to garden. A small yard or even patio can still be private and relaxing.

Many have taken to growing plants in containers which presents gardeners with endless opportunities to express their imagination and flair in these smaller situations.

One of the best things about container-grown plants is that they can be moved from one place to another.

This way you can give plants a suitable microclimate to grow and shift them around to prominence and show them off when they are at their best.

Choices include a fragrant plant by the front door, a cheerful bowl of spring bulbs, an immaculate piece of topiary or why not grow something edible.

You can grow almost any plant in a container, so it depends on whether you would like to brighten up a shady area or just provide some cool green relief from the hot sun.

It’s just a matter of choosing suitable plants for the particular conditions.

Once you have decided on a particular look or style, the next question is what sort of pot or container you should use.

There is a superb range available to choose from. Containers come in all shapes and sizes.

They are made out of many different materials and prices vary dramatically, mostly depend upon the degree of difficulty with which they are created.

Some of the types available are glazed earthenware (ceramic), terracotta, wooden containers or plastic pots.

There are many which have outgrown their original use and are ideal containers for growing plants.

Old troughs, cooking pots, coppers, wheelbarrows, baths, beach driftwood and pumice are often used.

Even old disused boots and gumboots are seen occasionally supporting herbs or other healthy plants.

If providing drainage holes presents a problem you can use a plastic pot inside raised on a small amount of gravel or chip stone and keep a check that they don’t get waterlogged.

Tropical gardening is becoming more popular with lush, dense plantings splashed with colour offering a retreat from the busy world. These look great in containers, a large pot can have a few different plants in it too.

Situation and soil

To grow plants successfully in containers you must select the right plant for your situation.

If it is a windy spot plants must be able to stand up to it. Sunlight and shade considerations are also important and will influence your choice of plants.

Sun-loving plants including vegetables require at least 4-5 hours sunshine each day to grow successfully so check the amount of sunshine before selecting plants that could turn out to be unsuitable.

All containers must have good drainage; otherwise, your plants can become waterlogged.

Most pots and tubs have one or several drainage holes 1-2cm in diameter.

Ordinary garden soil is unsuitable for pots because it does not drain well and can set hard.

Potting mixes available from garden centres etc, are generally manufactured from pine bark and pumice and are open and porous. They are free of weed seeds, soil pests and plant diseases.

Always purchase a good quality potting mix to obtain the best results.

In general, the more you pay for your potting mix the better the quality and the better the results will be.

From many trials I have done over the years I recommend Tui Pot Power or Ican Premium Potting Mix.

When potting up most plants it is best not to put a small plant in a huge pot.

Plants just may not thrive in over-large containers and some plants prefer to be crowded.

It is best to move a plant into a slightly larger pot when the previous one is full of roots.

When potting, leave a margin between the soil level and the rim of the container.

When watering fill this space slowly with water until it drains from the holes in the bottom of the container.

A mulch straw, bark chip or nuggets helps reduce evaporation and cools the surface soil.

Good drainage and frequent watering causes leaching of plant nutrient.

Regular small amounts of fertiliser are needed to keep plants growing strongly.

Always apply fertilisers to moist soil to avoid burning young roots.

The water-soluble or liquid fertilisers such as Ican Fast Food and Yates Thrive Liquid are suitable for regular liquid feeds. Slow-acting fertilisers such as Ican Slow Food, Ican Fruit Food for Pots, Yates Acticote, Tui Enrich Slow Release or similar are suitable to provide nutrients over a long period.

Always follow the manufacturer’s instructions on the label.

Too much fertiliser can have a burning effect on plants especially if the potting mix dries out.

Vegetables in containers

It truly is amazing how much produce one can grow in containers. Most vegetables in containers will grow faster and have a shorter time to harvest than those grown in the garden.

This is predominantly due to the higher soil temperature that a container will maintain as the sun shines on it and heats up the potting mix.

Herbs have long been grown in containers somewhere close to the kitchen where they can be quickly chopped and added to the evening meal.

More recently many are growing other vegetables. Lettuces are an easy starting point with a time frame of 4-6 weeks to harvest of some of the ‘fancy" leaf varieties, you only need a couple of pots and a small family can have lettuce every week of the year.

During the summer months tomatoes, capsicum, chillies, dwarf beans can all be successfully grown in containers.

At this time of year you can plant sugar snap peas up some bamboo stakes in containers, silverbeet – the rainbow coloured variety – is an eye-catcher in containers, spinach planted now can have leaves harvested when they are up to size and should continue to produce through autumn and winter until spring.

Even broccoli, cauliflower and cabbage can be grown in a decent size trough.

Smaller growing or “mini” varieties of these are available and are great for containers as they don’t take up as much room and have a shorter time to maturity.

The smaller size of the produce means these are great if you don’t want to eat cabbage every day for a week.

Fruit in containers

Growing fruit trees in containers has become very popular for a few of reasons, it gives a planting option when the garden is already full, it can help contain the size of the plant and you can take it with you if you move.

There are a number of fruits that can be successfully grown in containers including; dwarf peaches which are grafted on stem heights varying from 50-90cm and form a rounded topiary head.

These beauties have magnificent spring blossoms and fruit prolifically from their first year.

Citrus can make excellent container plants and will fruit successfully.

The secret of success for these is monthly fertilising along with daily watering during the summer months.

Positioning the citrus in a warm sheltered location away from the prevailing wind is also important to ensure success.

Bush-growing fruits such as blueberries, Chilean guava, and cherry guava can all be successfully grown in containers.

Happy Gardening.

Gareth Carter is General Manager of Springvale Garden Centre.