Container gardens

Gardening in Containers or in the Ground: What Do You Need to Know?

Container gardening has been on the rise for a number of years now. Once very marginal and mainly reserved for ornamental horticulture, container growing was the norm for flower pots, balcony planters or hanging baskets. I remember that, when I was a greenhouse flower and vegetable grower over 35 years ago, the only edible plants grown in window boxes or pots were herbs. Container growing was mainly for flowers.

Photo: He?le?ne Arsenault.

The Evolution of Container Gardening

Gradually, over the years, tomato plants appeared in large boilers, staked and already with tomatoes ready to ripen. These were offered to people in a hurry to eat something other than the hard, tasteless tomatoes that came from elsewhere, picked green to withstand the journey and forced to ripen once they reached their destination.

Container gardening found its niche in urban environments at first. It suited those who lacked ground space, but wanted to touch the soil and connect with nature. It also appealed to those who wanted to rely less on supermarkets, to be certain of the absence of pesticides, and also to those with the environmental concern of avoiding long-distance transport of fruit and vegetables.

The confinement caused by the coronavirus pandemic seems to have had a major effect on the popularity of container gardening. In an urban environment, what else was there to do but garden at home, since we were confined to our homes?

In our world, the market economy is always on the lookout for consumer trends. People without land wanted to garden, so the market for artificial cultivation began to flourish. Hydroponics, container gardening, growing in bags and pots of all kinds, specialized potting soils, fertilizers adapted to this mode of cultivation – a whole range of new products and techniques have emerged to satisfy the gardening tastes of landless people.

Growing in Containers or in the Ground?

However, this tempting offer wasn’t limited to those who didn’t have any land to cultivate. From the point of view of companies whose aim is to make a profit and increase their sales, anyone who wants to garden is a potential customer. For these companies, the aim was to promote their products to gardening enthusiasts who, faced with the challenges of soil cultivation, were looking for solutions to their problems. For example, how many people with space to garden have adopted raised beds to avoid having to bend over for maintenance? How many others grow in containers because there’s less weeding to be done? How many people believe that their land is unsuitable for gardening because it’s too sandy, too rocky, too compact or too wet?

Photo: Danielle Darveau.

In the Ground, My Experience

Yet all these conditions are easily corrected in the soil. I’ve proven this by understanding the laws that ensure plant growth. To prove it, I made a garden directly on an old beach volleyball court in 2016. It doesn’t get much sandier than that. And yet, from the very first year, my harvests were abundant, and with very little investment: fall application of aquatic plants harvested from the riverbank; mulch application of chopped leaves and freshly cut grasses after sowing and planting; liquid fertilization with worm compost tea diluted in 10 parts water four times in the season and applied under the soil thanks to the Logissol-O watering system (which provides my daily irrigation all season long requiring me to water only every 4 to 5 dry days).

No weeding was necessary thanks to the mulch, which also decomposes and feeds my crops. This volleyball court is now my main garden, and the once pure sand is now a sandy soil rich in organic matter, full of active life that ensures the fertility of my soil and, above all, the good health of my fruit and vegetables.

Sand garden, June 15. Photo: Serge Fortier.
Sand garden, July 8th. Photo: Serge Fortier.
Sand garden, July 30. Photo: Serge Fortier.

As an environmental consultant, my point of view is often different from what the market is offering. Is this new craze for container gardening, although it seems to meet certain criteria that growing in the ground would not, a step forward in environmental terms? For a gardener with even a small plot of land, wouldn’t it be better to show them how to prepare the soil and minimize the maintenance of a garden in the ground, rather than launching them into the practice of artificial cultivation?

The Differences Between the Two Methods

Here are just a few of the differences between growing in containers and in the ground:

Water

The majority of problems experienced in gardens and landscaping are due to inadequate watering. Just because you water doesn’t mean the plant will get what it needs. You need to water regularly and in the right place. This doesn’t mean watering regularly and keeping the soil surface moist. Let’s take an example: when you’re thirsty, is it thirst-quenching to pour 20 liters of water over your head? Would pouring just 10 liters at a time, but more often, do the trick? Of course not! 250 ml in the mouth would be enough, and much more thirst-quenching, wouldn’t it?

Photo: Jacques Gilbert.

In a previous article, I explained the law of capillarity in nature, where water rises from the subsoil like oil along the wick of an oil lamp. This natural source of water is constant and available to plants in nature, i.e. those in the ground. In pots and raised planters, plants lack this essential (and also free) source of water. In the case of bottomless containers, the fact that they are raised, i.e. out of the ground, affects the ability of groundwater to reach the surface, since the further away from the source you are, the less capillary action there is.

No surface watering is better than capillary watering. So even if you water and water, the regularity isn’t the same, and this stresses the plants. As a result, stressed plants mean weakened plants, and diseases and insects are more frequent and harder to control. This is another fundamental law of the environment. It’s always the weakest beings that are attacked by predators!

Soil

When growing in containers, you need to use a growing medium other than the “real earth” that makes up the soil on your plot or even the soil in your garden. You need to buy or make your own potting soil that stays light and airy, retains water and fertilizers, and doesn’t compact when watered (because watering can only be done on the surface, except for those who use a Logissol-O-style system, i.e. one that allows you to water under the soil without going over the top). Natural soil would become too compacted with such treatment, so the market offers artificial potting soils and growing substrates that avoid this problem.

However, while these potting soils avoid compaction, they bring other complications. Firstly, they are sterile in terms of vitality, and we know that in nature, it’s the life in the soil that makes it fertile and helps plants grow healthy. Artificial potting soils don’t have this life in them, so they have to be balanced in the laboratory to provide the nutrients plants need. The trouble is, as soon as you grow something in this substrate, these elements are absorbed and become lacking for the next crop (or even the first crop, if it’s fertilizer-intensive).

In the Ground

In natural soil, the life in the earth balances the elements thanks to the organic matter produced by the decomposition of crop residues. This is not the case in an artificial environment devoid of the normal soil ecosystem. With no laboratory at home to analyze potting soil, we’re left to our own devices to guess what’s missing from our potting soil to ensure the growth of our vegetables. The result: if things aren’t too bad the first year, it can be difficult to get yields in subsequent years. Because there’s immediate fertility and long-term fertility! Fertilizers bring immediate fertility, but it’s the earthworms and all the other living beings in the soil that bring long-term fertility. But where are these earthworms in a potting soil? There aren’t any!

What’s more, from an environmental standpoint, the exploitation of natural environments to produce these potting soils has increased considerably since the craze for this method of cultivation began. Peat bogs are natural environments with the capacity to capture GHGs, and they are being exploited at breakneck speed. Most of these peat bogs are located between 400 and 800 km from major urban centers. This generates a lot of GHGs for transport. I agree with the perfectly logical argument of wanting to eat local vegetables. But if that means transporting the inputs needed to produce them over long distances, where’s the real gain? In fact, all we’re doing is shifting the problem.

Temperature

The potting soil in containers and tubs will tend to warm up faster and also become warmer. This can be an advantage if you’re growing heat-demanding crops such as peppers, chillies, ground cherries, sweet potatoes, eggplants, cucumbers, zucchini and even tomatoes. On the other hand, it can be a double-edged sword! If the soil in containers warms up faster, it also cools down faster as the temperature differences between day and night increase. This will have an impact on the health of plants, which, stressed by too sudden a temperature variation, will be more vulnerable to fungal diseases. What’s more, during the heat of summer, potting soil becomes very hot, which increases evaporation and hence the need for watering. Watering with cold drinking water creates a temperature contrast that the plant won’t like, and will have an impact on plant health, resistance and yield.

YieldLe jardinage en bac a pris de l’ampleur depuis quelques années. Voici les différences entre la culture en bac et celle en pleine terre.

Growing in containers and planters can produce high yields. However, from an environmental point of view, you should always try to do as much as possible with as little as possible, i.e. get the maximum yield with the least possible resources consumed, the least possible maintenance effort and the least possible monetary investment. Compared to a garden in the ground, container gardening is a long way behind.

Photo: Louis-Claude Perron.

Un autre point majeur à considérer qui réduit la chance d’avoir du rendement, c’est le faible volume de terreau ou d’espace pour le développement des racines. Jamais on ne pourra offrir le même volume de sol dans un contenant qu’en pleine terre. J’ai déjà arraché un plant de tomate à la fin de l’automne et celui-ci avait des racines de 2 mètres allant dans toutes les directions. Qu’en est-il lorsqu’on confine un plant dans un contenant de 20 litres? De plus, avec de petites surfaces de culture comme les bacs ou les pots, on a tendance à mettre trop de plants. Au début de l’été, ça n’a pas l’air serré, mais quand les plants prennent de l’ampleur, la densité de feuillage devient trop grande et cela affecte le rendement et augmente les risques de maladies par manque d’aération.

While gardening in a container means you’re not dependent on outdoor produce, it also means you’re dependent on all the inputs you need to do it. The purchase of potting soil, containers, special fertilizers, treatments, and not to mention watering which increases drinking water consumption. The huge watering needs of container crops exceed the rainwater storage capacity of most people.

In Conclusion

In conclusion, please don’t see my article as a disparagement of container-growing. I’m simply stating the facts, because it’s not just a personal opinion. As for my personal opinion, faced with these facts and my desire to simplify my life, I prefer to prioritize growing in the ground because I have the choice, by having a piece of land. If you have even a small piece of land and you want to grow good crops with less maintenance and less disease, growing in the ground is and always will be the natural way to grow fruit and vegetables. Container gardening remains the only option for people without land or available soil, because they have no choice! But that doesn’t mean you’re immune to the facts explained in this article. You’ll have to take them into account, and you’ll inevitably be confronted with this reality.

As the saying goes, “Forewarned is forearmed!”, I hope this information will help you plan accordingly if you’re growing in containers or bins.

Happy fall gardening!

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Serge Fortier is an environmental and environmental gardening consultant with over 40 years of expertise and observation of plants and their environment. He stands out for his logical practices, which respect environmental laws above all else, and which he shares at conferences, in training courses, as a consultant and in his books. A skilled popularizer, he guides the public in understanding the plant world that surrounds us. He has mastered the management of organic matter at source, the management of drinking water for the garden and the management of aquatic plants. His motto: Do more with less! More results with fewer problems, less expense and, above all, less effort! Laidback gardening isn't laziness, it's intelligence!

1 comment on “Gardening in Containers or in the Ground: What Do You Need to Know?

  1. Kevin Phillips

    Thanks for the good thoughts on the fundamental differences between these two growing methods. And unless I missed it, another downside to the container approach (for perennials, at least) is how to over-winter them, unless they are treated as disposable in the fall. I was glad to see you noting the environmental downside of extracting peat, because Canada’s gardening market seems to be generally indifferent to this.

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