Plants need sunlight to make food – it is gardening 101. More sun means plants grow strong and healthy. Even a rookie gardener knows that. But as the saying goes, you can have too much of a good thing. The same is true for sunbathing your green buddies.
Can too much sunlight damage your plants? Excessive sunlight can cause your plants to sunburn. Your plant will accumulate damages from repetitive exposure to too much sunlight. These damages will ultimately cause the plant to dehydrate or die.
Let’s walk through all the details of how sunlight affects plant growth, How excessive amounts damage your plants, and what you have to do once your plants got sunburnt.
Too much sunlight can hurt your plants
Giving your plants more than their recommended quota of direct sunlight can sunburn them. Kinda like what happens to you when you forget to bring your sun-screen to the beach. To be more precise, excessive sunlight creates heat. Your plants need to shed this heat for which it uses its water contents, thus dehydrating them.
Besides, exposure to intense sunlight causes plants to reach an over-oxidated state. This happens when the molecules responsible for photosynthesis – chlorophyll and carotenoid – get overheated and start producing harmful oxidants that damage the plant.
Plants that produce fruits and vegetables suffer dearly from overexposure to the sun. To protect themselves from complete dehydration, plants slow down or even shut off growth and reproduction. This leads to a poor harvest and a low yield.
As you can guess, this isn’t something you’d want your leafy friends to go through. Gardeners living in warm and sunny areas need to keep a tab on the sun-time their plants are getting.
The optimal amount and intensity of sunlight
Different plants have different sunlight needs. There are bright-light plants that love direct sunlight, medium-light plants like a little filter between them and the sun, and low-light plants with no need for direct sunlight. Give your plants more sun than what they are made for, and you could very well be scorching them.
If you live in a sunny part of the country, you need to take care of the solar exposure your plants are getting, especially during summer. Even your bright light plants may show signs of sunburn if you leave them out in the open all day long. A good practice for such plants is to give them their needed quota of direct sunlight early in the day and have some means to protect them from the harsh afternoon sun.
As for your Half-Shade plants, they should get 3 to 6 hours of early-day sunlight. It is best to grow them under a shaded area where the afternoon sunlight is indirect.
Full-Shade plants don’t need direct sun and should strictly be kept in shaded areas or indoors, albeit in a lit area. These plants can get all the necessary solar energy from ambient daylight.
How too much sunlight affects your plants
In forests, most of the sunlight is hogged by big, thick trees. This leaves little direct sunlight for anything on the forest-bed. However, many plants have evolved to make do and thrive with this minuscule sunlight. Most common houseplants such as Pothos, Philodendrons, Alocasias, Monsteras, Aglaonemas, Arrowhead vines, Colocasia, and Ferns live that kind of life naturally. At home or in your garden, these plants have to be kept away from direct sunlight, for they have adapted to live without it, and keeping them out in the sun could kill them.
Some plants are full-time outdoor plants: they need direct sunlight for at least 6 hours a day. But even those plants can get too full of sunlight. For instance, plants that are native to a colder region may not fare so well in the intense summer heat of a warmer area. If your garden is in such parts of the world, try to minimize your outdoor plants’ noon sun exposure and give them plenty of morning and evening sunshine instead.
Unless your outdoor plants are hardy to hot, dry climates, they need to stay hydrated to thrive under the summer sun. Intense heat uses up more water. If your plants aren’t getting plenty of water to survive the sun, they may wilt and eventually dry out.
Your plants will tell you if they’re getting sunburnt
Speaking of wilting, it is when a plant’s leaves shrivel up or become limp. It is a sad sight to behold. But in reality, it is a defense mechanism that triggers when plants don’t want to lose any more water to the sunlight. Wilting reduces the leaves’ total surface area, thus making them absorb less sunlight and, consequently, less heat. While this happens, plants also shut their pores to avoid further evaporation of water.
Plants cease their growth when wilted, and if your plants are often wilting, you need to give them shade, start watering them more, and reduce their daylight intake. Wilted leaves recover soon after you move them to a shaded place, water them, or when the sun sets.
Telltale signs of plants getting too much sunlight appear on their leaves. Aside from wilting, the leaves start getting yellow or white spots, which turn brown, and ultimately black, if sun exposure isn’t controlled.
Excessive sun requires the plant to suck up more water from its roots. If the soil is dry and hard, it means there won’t be enough water for the roots to extract, and your plants will dehydrate and wilt. Water your plants thoroughly, without going overboard – too much water can rot the roots. Water them just enough so the soil stays slightly damp until the end of the day.
My plant got sunburnt! What do I do?
Well, the first thing you have to do is remove them from the sun. This is easy if your plant is in a pot. For plants that are growing outside in a garden, that’s not an option. What you can do to prevent further damage is to provide the plant with some shelter.
Make sure the shade doesn’t cover the plant from all sunlight; as for outdoor plants, some sunlight is still necessary. The shade should ideally reduce the intensity of the harsh midday sun while still letting through the morning and late evening sunlight, as well as ambient light.
Another immediate action to take is to water the plant thoroughly. Plants getting damaged from too much sun are likely dehydrated, and watering them properly should help their roots absorb enough moisture to rejuvenate the wilted leaves.
Avoid dumping buckets of water on heavily dehydrated plants. Their cells will start to absorb all the water they can, which can cause cracks and tears in the plant’s cells. It’s best to use a steady, low-intensity stream of water for your plants until they are fully hydrated again.
How can I protect my plants from sun damage?
Aside from proper placement and regular watering, there are other steps you can take to ensure your vegetation doesn’t wither under the sun.
Know before you sow:
Always read up on the habitat of a plant you’re planning to grow. Study its preferred climate, irrigation requirements, and sunlight to help pick the ideal spot for it to occupy.
Let the roots spread
A plant can survive excessive sun rays if it can soak up enough water from its roots. However, some conditions hinder the roots’ ability to function at their fullest. This may include:
- Diseases like
- root rot
- fungal growth
- insect infestation
- Hindrances that confine root growth such as small pots or a nearby pavement
- Hostile growing conditions
Make sure the roots have ample room to grow and are healthy enough to absorb as much water as the plant needs.
Hardy your sheltered plants
Greenhouse plants are more sensitive to sunlight and shouldn’t be moved outside without some adjustment-time. Such plants have adapted to the greenhouses’ filtered light, and moving them outdoors without giving them time to adjust will increase the likelihood of them getting sun-damaged.
Give such plants a little direct sun at the start – a couple of hours tops per day should be enough. Slowly increase the time they spend in the sun week-by-week, and by then, the plants should be strong enough to be left out in the sun unattended.
Irrigation during cool hours
Avoid watering your plants when it is too hot outside. Under intense heat, the water would evaporate quickly. This will not give the soil much water to absorb and prevent the water from reaching the roots. The best times for irrigation are early morning and late evening when the sun isn’t at its worst.
Don’t let water be the cause of sunburn
When watering your plants, wash their leaves to remove dirt and reduce the plant’s overall temperature. However, this is best done during the early hours when the sun isn’t bright. Water droplets on leaves may function as tiny magnifiers for the bright sun and amplify sunburn chances.
Be wary of windows
Even if the sunlight doesn’t feel all that harsh, it can still intensify after passing through a glass window. If your plants are at a spot where they’re getting long hours of sunlight passing through a window, they’re at risk. Should the plant show any signs of sun damage, it should immediately be moved.
You should also be wary of intense sunlight bouncing off nearby buildings and other reflective surfaces. Some glass buildings have been known to magnify light to scalding temperatures.
Mind the wind
Most people don’t even consider wind as a possible cause of sun damage. Frequent winds take away the plant’s water contents, causing excessive evaporation. This can lead to plants getting dehydrated. That way, even if the sun isn’t hot enough, scorching can occur.
A potent way to prevent harsh afternoon sun from burning your plants is to have them shaded just enough to lessen the hot sun’s intensity while still allowing evening and morning sunshine through.
Fabric should be your material of choice for cheap and easy covering for your flora. Unlike plastic sheets, fabric sheets allow for proper air circulation, crucial for better growth of vegetation. Just make sure to remove them if the weather gets cold or by nightfall.
Mulch the ground
If you want to ensure prolonged hydration of the roots, consider adding mulch under your plants. This will lock in the moisture and keep your plants’ roots aptly irrigated for the long, hot day.
Humidify if needed
For some tropical plants like ferns, soggy soil isn’t enough. They also need a wet environment to thrive. This isn’t practical if you live in a hot and dry area, in which case such plants can get sunburnt quicker. One solution would be to place a plate filled with water and pebbles under the plant. The evaporating water will keep the air around the plant nice and moist.
Plant seeds deep
If you expect high temperatures, planting your seeds an inch or two deeper than usual would ensure the summer sun doesn’t scorch the young plant’s roots. Also, by the time the plant shoots from the ground, it would be slightly older and stronger and better suited to survive the sun.
Will too much sunlight kill my plants?
Plants get severely weakened when suffering the effects of a sun-scorch. A plant’s leaves are responsible for making the food necessary for the plant to grow. When scorched or dehydrated, the functioning of leaves is severely affected, resulting in stunted growth.
The plant is vulnerable at this point, and prolonged weakness may attract insects, fungi, and diseases.
Prolonged dehydration causes leave discoloration, effectively rendering the burned part of the leaf useless. However, as long as the leaf is attached to the plant, it will consume sustenance. The plant will try to revive the dead bits to no avail, leaving no food for proper growth. As you can guess, this will result in your once-green buddy either dying or inching closer to its demise.
Of course, even if the plant “appears” dead, it may not necessarily be the case. Scrutinize the plant for any signs of life. The leaves may have fallen off, and the branches may be fragile, but if the stem shows green coloration and appears firm, or if the roots don’t appear brittle, then there is still hope for revival.
Should I snip off sunburnt leaves?
Definitely! That is the first thing you should do if you want to revive your dying plant. As mentioned before, dead or dying leaves still draw nutrition, for the plant keeps trying to restore its function. Do your foliage a favor, cut the dying parts off so the plant can focus its energy on keeping the healthy parts alive and well.
Now, should you stop at the leaf, or should you chop the branches as well? That depends. If the branch is green, then only remove the leaf. For a brown branch, try scratching off its top layer. If this doesn’t reveal any green inside it, get rid of it. If you want your plant to revive, it should have no dead bits to deal with.
The leaves that have been scorched are beyond help. There is no way you can hope to make them green again. So cut your losses, hack the dead bits off, and let your plant grow new leaves. Take better care this time, and don’t let your plants get sunburnt again.
Bringing dying plants back to life
Take the plant to the shade
Alternatively, you can take the shade to the plant. Either way, your plant should no longer get direct sunlight. Potted plants can be easy to carry and can be brought indoors for the ensuing recovery process. A shade can cover vegetation planted in the garden for the duration of their resurrection. Ensure the shade allows for ventilation and isn’t placed so close as to prevent butterflies, bees, and other helpful insects from reaching your plants.
Cut your losses
Get rid of the dead bits. Snip off any leaves, branches, or parts of the stem that is dead. As mentioned before, your plant would otherwise be wasting valuable resources to try and nourish those dead parts. After you do away with the dead bits, only then can you move forward with the recovery.
Repot if needed
A plant may not be getting the desired hydration if the roots can’t grow to their full capacity. Consider repotting your plant in a bigger space to ensure the roots have ample room to grow. This will ensure that the plants get to absorb plenty of moisture to transport up to the leaves.
You might be tempted to water your plant multiple times a day if it was a victim of scorch. However, once you trim the dead leaves off the plant wouldn’t need too much watering. This excessive water may contribute to root rot.
You may also be tempted to use excessive fertilizer, thinking this will help nourish the weakened plant. I would strongly advise you not to do that.
A sunburnt plant with its leaves lost would require much less sustenance to function. You should actually reduce the fertilizer you were giving the plant before it suffered sun damage. Either cut down the amount of fertilizer or reduce the frequency of fertilization.
Once your plant starts showing signs of recovery, you may gradually increase the fertilizer dosage back to normal.
Sunburn is one of the leading causes of plant demise, especially in hot areas. Special care is warranted by the fauna planted in such places. Regular irrigation, proper placement, and humidification of the plant’s environment can ensure your leafy buddies grow big and strong. Pay attention to the plant’s sunlight requirements and never expose it to elements it isn’t accustomed to.