Container Gardening, by Sandy Hutt, EHS Member

Have you ever tried gardening between large roots of trees? Would you like to plant more vegetables and flowers but do not have the space? Perhaps your garden soil needs an expensive transformation? There are a number of reasons you may want to increase or change your garden footprint or, plant in areas easier to maintain and access. There are a number of other advantages of container gardening. One suggestion from my research was that, if by chance the weather gets inclement, you can move the containers to a more protected area or even indoors.

Just by "accident" I stumbled into container gardening and discovered for myself that there are many advantages to this method of growing plants.

Placement of Containers

By placing containers close to your back porch, you might be able to access vegetables and herbs just by stepping out your kitchen door.

Planting flowers and vegetables farther away from the house gives one a better view of how each component adds to the overall appearance of the garden. Placing flower containers in front of the house adds splashes of colour and adds to curb appeal.

Placing containers in existing flower beds allows the gardener to add variety to the garden. It makes it interesting to add vegetable containers into a flower border or to fill any spaces or areas difficult to grow plants.

Containers placed above the ground level flower or vegetable beds can serve as focal points of the garden. That is where the gardener's artistic ability comes into play. Experiment! In addition, containers placed on raised objects such as tree stumps, rock outcrops or rock arrangements may be used to impede damage that could be done to crops by our cute little visitors, the rabbits.

Balconies:

Containers on balconies extend growing space. Not only do they provide serenity and tranquility in the midst of a busy city, but also provide extra food sources and reduce the expense of buying fresh produce.

General Information:

One can spend a lot of money in buying beautiful containers from a store, or, one can transform discarded containers of any kind into acceptable, whimsical, artistic spaces where the plants become the main performers. One can get old planters, bushel baskets (or any large baskets), or large pots from a recycling area of a nursery. Take advantage of that. One should also consider the placement of these containers. Black containers absorb sun's radiation and heat up whereas light, or white containers tend to reflect sunlight and roots stay cooler. Fortunately, we live in Southern Ontario, where the summer temperatures are not too high, therefore, the colour of the container may not create a problem. Be aware, that containers placed in the sun will heat up more and will require more water than containers in the shade.

If you have containers that tend to heat up, you can move them to an area where the exposure of the sun is lower or you can insulate or paint them. Afternoon sun tends to heat up objects more, so placing plants in an area where they get most of the morning sun may prevent this problem. Most vegetables require between 8 and 12 hours of sunlight every day in order to produce flowers and for the proper ripening of fruit. However, there are many leafy vegetables which will grow in areas where the sun exposure is four hours a day or less. Of course, they do much better in sunnier locations but if you mainly have shade, you can still grow produce.

Make sure all the containers used for plants have holes on the bottom or on the sides of the bottom for drainage. Plants do not like wet feet and tend to succumb to root rot.

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Container sizes:

Decide what type of plants you want to grow. Determinate variety (bush or patio type) of tomatoes or other vegetables are bred so that the mature plants stay fairly compact and produce most of the fruit within a short time span. Containers 8-10 gallons (30-38 litres) capacity would be sufficient to grow large plants such as determinate tomatoes or eggplants. Indeterminate tomatoes would require four times that volume of soil. Five gallon (3.8L) pots would do well for plants like chard and kale. For herbs, one can use 1-2 gal (3.8-7.6L) pots. These smaller pots for herbs or leafy vegetables would not need to be as deep.

A number of references suggest different sizes of containers for different vegetables. One website that has a comprehensive chart of vegetables and container sizes is the San Diego Seed Company, https://sandiegoseedcompany.com/container-garden/vegetable-container-size-chart/ Another source of information could be Google Search "sizes of containers for growing vegetables".

Soil

Besides having a drainage hole in the pot, another important factor in growing vegetables in containers is to use the correct soil mix. Garden soil and top soil are too heavy or compact too easily and do not drain well. Containers need a potting soil mix. You can buy that ready prepared. If you find that too expensive because of the amount of soil needed, you can mix your own potting soil by using 1/3 coco coir or peat moss, 1/3 compost and 1/3 perlite. This potting mix will retain the right amount of water, yet it will drain well. In addition, this mixture can be, and perhaps should be, amended with a granular organic slow release fertilizer and a couple of handfuls of worm castings. Container plants are limited to the nutrients available to them in the soil mix provided. It is, therefore, beneficial to the plants to supplement this even more by using water soluble fertilizer weekly.

Soil for growing flowers in containers is not as crucial, especially since one can reuse old soil, as I do, leaving small dead roots of plants from the year before. This keeps the soil from compacting and allows for good drainage. Soil mix used in previous years can also be used for new vegetables as long as the previous plants were disease free. Make sure you amend it by adding some fresh mixture and fertilizer.

Mulching

Mulching has many benefits both in the garden beds and in containers. It reduces evaporation of moisture from the soil surface, minimizes the growth of weeds and regulates soil temperature. A good idea is to use an organic mulch as it will break down and add organic matter to the soil. For containers, mulch, such as rice hulls, is very good even though it will last only one season. It is light weight and similar to sphagnum peat moss and coco coir. The difference is that it is pH neutral as opposed to being acidic like the other two. Rice hull mulch usually lasts only one season, but then it can be incorporated into the potting mix, instead of adding more perlite. If you live in a windy area, you might want to use something heavier like shredded bark. When filling up containers with the potting mix, it is wise to leave about 4" (about 10 cm) at the top in order to put in about 2" (5 cm) of mulch. Keep the mulch from touching the plants to avoid rot.

Companion Planting in a Container

Gardeners usually grow one type of vegetable in a single container. However, you may want to have some variety and grow more than one. Containers with flowers, on the other hand, often are made up of a variety of plants with flower colours that complement one another. For best results, plants with similar nutritional, light and water requirements should be planted together. If not, some plants may not survive. Most vegetables need sunlight for fruit production while others can survive in partial shade. There are sun loving flowers and there are flowers that thrive best in partial shade or shade and will burn when exposed to direct sunlight. Do your homework. Know your plants.

Most Important points to remember:

1) Containers must have drainage holes.

2) Use soil that is a potting soil mix.

3) Use the appropriate size of a container - larger is better. It will retain water better.

4) Enhance the soil mix with fertilizer and/or water with fertilizer weekly.

5) Use a mulch.

6) Group plants that have similar growing requirements.

7) Plants in containers are moveable.
You can use plant trollies or caddies in order to move larger plants more easily.

References:

How to Grow a Container Garden, Cheap and Easy Patio Gardening:

https://www.youtube.com/watch?v=GTrrpF1prOY

How to grow tomato plants in pots (Gumbo Gardening)