How Much Light Do Plants Need?

Licht und Zimmerpflanzen

For a lush plant splendor in his garden, the hobby gardener must not only supply his plants with water and nutrients. Instead, he must also ensure that his plants get enough sun and thus energy. After all, unlike humans, a plant can’t just go somewhere else if it’s hungry or doesn’t feel right in one place.

Three different categories are used to indicate the light requirements of plants. The common classifications are based on the average number of hours of sunshine available at a particular location during the course of a year. On this basis, a distinction is then made between the following categories:

  • Sunny location more than six hours of full sun per day
  • Partial shade between three and six hours of full sun per day
  • Shady location less than three hours of full sun per day

However, the transitions between the categories are rather fluid. For example, a plant that prefers a full-sun location may well feel very comfortable in a place where it can soak up the full sun for only four hours. Conversely, for a plant that likes to be in the shade, a location with only two hours of midday sun may be unsuitable. In addition to the pure hours of sunshine, it also always depends on the conditions on site. For example, the actual light conditions also depend on the time of day when the location is in the sun or whether there are plants nearby that provide shade at certain times of the year through their foliage.
When in doubt, move to partial shade
In general, most plants can be placed in a partial shade location. This applies to plants that inherently prefer partial shade, as well as plants that prefer sun or shade. This is because a partial shade location is something of an intermediate solution, where sun and shade are balanced. So the plant gets here not too much, but also not too little light. If the hobby gardener is unsure of where best to place his plant, he can therefore first try a partial shade location. Most often, the plant will grow and thrive here.

However, the amateur gardener should not plant his plants in a completely unsuitable location. In most cases, this will not work. For example, a plant that needs a lot of sun will hardly grow, much less bloom, in a shady location.

Plants for the sun, partial shade and shade.
When considering the light requirements for their plants, amateur gardeners can be guided by where the plant in question is native to. Plants that originate from warm and dry desert areas logically need more sun and heat than plants that originally grew in cool, shady forests. And so that the assignment works better in the future and the hobby gardener can more easily find the optimal location for his plants, we have compiled a small overview with common garden plants and their preferred locations in the following sections.

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Pflanzen brauchen Licht - Aber wie viel? - Velanga

Plants for the sun


Plants with high light requirements are often native to desert areas, the Mediterranean, and the arid regions of Africa, Asia, and South and Central America. In addition, most plants that bear profuse flowers need a place in the sun. Flowering plants can often be planted in partial shade. As a rule of thumb, however, the darker the location, the fewer the flowers.

Here are some garden plants that need a lot of sunlight:

Flowers and herbsAdonis floret, arnica, basil, mugwort, borage, dill, tarragon, daisy, jasmine, chamomile, coriander, cornflower, caraway, lavender, lovage, daisy, mint, carnation, marigold, larkspur, yarrow, sunflower, pansy
Vegetable plantsEggplant, Bean, Broccoli, Chinese Cabbage, Endive, Fennel, Cucumber, Carrot, Potato, Garlic, Pumpkin, Pepper, Tomato, Onion
Fruit plantsApple, apricot, pear, blackberry, strawberry, fig, olive, nectarine, peach, plum, quince, black currant, sweet cherry, citrus fruit

Plants for partial shade
Plants that grow in the wild in sparse forests or forest edges usually prefer a partial shade location. A place with sufficient light, but without blazing midday sun is also ideal for plants with large and soft leaves. This is because a lot of water would evaporate through the leaves in the midday heat, which could cause the plants to wilt quickly.
Plants that are well suited for a location in partial shade are, for example:

Flowers and herbsFragrant violet, chervil, bay, marjoram, oregano, primrose, tansy, cowslip, juniper, lemon balm
Vegetable plantsPea, garden cress, kale, head cabbage, chard, radish, beet, lettuce, Jerusalem artichoke, white turnip
Fruit plantsapple, blackberry, blueberry, medlar, plum, red and white currant, gooseberry, wild strawberry

A large part of the plants, which actually prefer a bright and sunny location, can also be planted in partial shade. Sometimes the plants do not grow as big and strong here, but they still grow and thrive. So it may be worth a try if true sunny spots in the garden are limited.

Plants for the shade
Plants that thrive in shade are typically plants that thrive in the shade of other plants and trees in the wild. Often such plants are quite compact, do not grow too tall, and score high visually with their small, robust foliage.
Garden plants that thrive in the shade include:

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Flowers and herbsBearberry, Scented Violet, Cushion Primrose, Ruprecht’s Weed, Rock Periwinkle, Sweetthumb, Meadow Foamwort
Vegetables plantsGarden cress, kale, spinach, chard, Jerusalem artichoke
Fruit plantsMorello sour cherry, wild strawberry

Why do plants actually need light?


It should be clear to everyone that plants, like humans and animals, need light. But why is that actually the case? Why can’t plants grow without light? The decisive keyword in this context is photosynthesis. And the principle behind it is as follows: A plant absorbs water and nutrients from the soil. From the air, in turn, it extracts the gas carbon dioxide. The plant converts the water, nutrients and carbon dioxide into sugar and oxygen. In this way, the plant creates the food it needs to grow and thrive. But the plant needs energy to convert these substances. And this energy is supplied by light, which most plants absorb through their green leaves. Light is therefore the source from which the plant derives its power.

How much light a plant needs varies. For example, there are plants that need a lot of light to develop optimally. Other plants get by with less light, and still other plants need just a little light. But no plant can survive completely without light. By the way, it is easy to observe how important light is for plants. Many plants tend to grow in the direction from which the light comes.

What are the most important criteria when choosing a location?

Whether useful plants or purely ornamental plants, whether flowers, vegetables, trees or grasses, whether native classics or real exotics and whether plants for planting out or for planters: When strolling through the garden market, the hobby gardener encounters a huge range. But even if his fingers are itching, the hobby gardener should proceed with caution when selecting his plants. Because if the general conditions are not right, the respective plant will not thrive optimally.

Very important in this context is the condition of the soil. For optimal growth, different plants have very different requirements. For example, some plants need a loose, permeable and nutrient-rich soil. Other plants feel comfortable in a heavy, loamy soil, and still other plants are content with a nutrient-poor sandy soil. By using the right substrate and fertilizing accordingly, the amateur gardener can create optimal conditions here.

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Another criteria on on which the hobby gardener can have little influence, however, is the climatic conditions. Especially plants that are native to warm regions often cope poorly with our cool winters. Such plants should therefore be cultivated by the hobby gardener in the first years best in the tub and winter well protected from the cold in a frost-free room. If the plants are older and more robust, it is sometimes sufficient for the amateur gardener to protect them from frost damage with straw, leaves, fir brushwood or a fleece.
In addition to temperatures, the amateur gardener should also consider the wind. Many plants are quite sensitive when exposed to drafts or strong gusts of wind. Plants with large leaves or vigorous flowers, for example, are usually better off in a wind-protected location, while plants with small leaves or needles have fewer problems with a windy spot. Some of them can even be planted as windbreaks. As soon as wind and also sun come into play, however, watering also becomes an issue. Because both can dry out the soil quickly, so the plants then need correspondingly more moisture. And last but not least, of course, the light conditions at the location also play a central role.

But do not worry!

It will always happen that the amateur gardener cannot fulfill all the wishes of his plants. Nevertheless, the amateur gardener does not have to do without his desired plants. He should then only make sure that the location and care meet the other requirements.
Suppose a plant prefers a bright and sunny place, sheltered from the wind. It needs a lot of water, requires a nutrient-rich soil and regular feeding with additional fertilizer. In addition, it is not hardy. The amateur gardener can certainly place this plant in partial shade. However, in order for the plant to feel comfortable, the amateur gardener should meet all other requirements if possible. So, he should choose a place protected from the wind, water the plant abundantly and fertilize it regularly. In addition, he should winter-proof it in time before the first frosts or bring it inside.

Author

  • James Jones

    Meet James Jones, a passionate gardening writer whose words bloom with the wisdom of an experienced horticulturist. With a deep-rooted love for all things green, James has dedicated his life to sharing the art and science of gardening with the world. James's words have found their way into countless publications, and his gardening insights have inspired a new generation of green thumbs. His commitment to sustainability and environmental stewardship shines through in every article he crafts.

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