Mango Sun Damage: Treating Mangoes With Sunburn

Mango Sun Damage: Treating Mangoes With Sunburn

By: Bonnie L. Grant, Certified Urban Agriculturist

Did you ever apply a magnifying glass to an ant? If so, you understand the action behind mango sun damage. It occurs when moisture concentrates the sun’s rays. The condition can cause unmarketable fruits and stunt them. Mangoes with sunburn have reduced palatability and are usually used to make juice. If you want to save the juicy fruits for out of hand eating, learn how to stop mango sunburn in your plants.

Recognizing Mangoes with Sunburn

The importance of sunscreen in humans is indisputable but can mangoes get sunburnt? Sunburn occurs in many plants, whether fruiting or not. Mango trees are affected when grown in areas with temperatures that exceed 100 degrees Fahrenheit (38 C.). A combination of moisture and high sun and heat are the culprits of mango sun damage. Preventing mango sunburn occurs with either chemicals or covers. There are several studies on the most effective methods.

Mangoes that have become sunburnt have some portion, usually the dorsal surface, that is dry and shrunken. The area appears necrotic, tan to brown, with darker lining the edges and some bleed around the area. Essentially, the area has been cooked by the sun, just as if you held a blowtorch to the fruit briefly. It occurs when the sun is scorching and water or other sprays are present on the fruit. It is called the “lens effect” where the sun’s heat is magnified on the skin of the mango.

Preventing Mango Sunburn

Recent developments suggest that several chemical sprays can help prevent sunburn in fruit. A trial in the Journal of Applied Sciences Research found that spraying a 5 percent solution of three different chemicals caused significantly less sunburn and fruit drop. These are kaolin, magnesium carbonate and calamine.

These chemicals deflect radiation and the UV wave lengths that touch fruit. When sprayed annually, they reduce the temperatures that reach the leaves and fruit. The trial was conducted in 2010 and 2011 and it is unknown if this is now a standard practice or still undergoing testing.

For quite some time, mango farmers would put paper bags over developing fruit to protect them from sun damage. However, during rain, these bags would collapse over the fruit and promote certain diseases, especially fungal issues. Then plastic caps were used over the fruit but this method could cause some moisture build up as well.

A new practice uses the plastic “mango hats” that are lined with wool. Embedded in the wool lining are beneficial bacteria and a copper compound to help combat any fungal or disease issues. The results with the woolly hats showed that less sunburn occurred and the mangoes remained healthy.

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Sunscald, sometimes referred to as southwest injury because it usually occur on the south- and west-facing sides of the trunk, tends to affect young or thin-barked trees when they are leafless in winter. It can also affect heavily pruned trees if the trunk is exposed to intense sunlight and experiencing temperature fluctuations. Sunscald damage, which appears as discoloration, cracking or sunken areas on bark, causes stress to the tree and creates an opening for pests and disease. Sunscald problems are avoided by tree painting with whitewash or a certain type of paint.

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Sure you can, 2 members that I know that have are Ohiojay and lycheeluva. I believe they're both in zone 5 or 6. Ohiojay utilize a greenhouse and grows more than just mangoes and lycheeluva in New York just puts in his spare room for the winter. Both of them can attest to growing bearing mangoes up north and what's is more amazing is a member who move to Iceland and brought with her, her plants and got her mango to bear fruit in a green house. So anyone can basically grow a mango and have it bear fruits, just need the right equipment.


I'm one of the guys that grow mangoes up north (Canada). It is really possible, but you'll need some supplement lighthing in the winter if of you don't have a greenhouse. Otherwise they will not thrive.


I have a greenhouse but I am wondering if anyone has ever gotten their tree to fruit and be edible? Nice a sweet like they pick them in the south?

I have seen many growing them, but have yet to actually speak to someone that has picked a fruit. I am beginning to think that even a greenhouse with such a lack of long days and hot real sunshine won't even do.


I am going to bump this thread to the top until I see a picture of someone's tree here, and know that a Mango tree can successfully put out edible sweet fruit in my northern climate.

I do have the advantage of a greenhouse, but I am still left doubting.

If soneone here has had this success and I find out by April, then I will most certainly order one. I do have the option to buy a grafted one that claims to fruit to maturity in my climte but I don't believe


Try contacting the members Ohiojay and lycheeluva, they are both also in the colder climate state and has gotten theirs to fruit. I'm not sure how the taste would compare to southern states tree ripen mangoes, but it will still be better than store bought mangoes which are picked too early. Are the ones you're considering the condo mangoes ie: carrie, julie, cogshall, pickering? These will do fine in pots since they don't get very tall 8'-10', but can be mange to size of 5'-6' by pruning. I will send those 2 member a email and see if they will respond to help you out.


Several members have been successfully growing and fruiting not only mango, but others such as lychee, jaboticaba, grumichama, dragonfruit, miracle fruit, sugar apples, papaya, and many more in the northern states. The fruit are full sized and have tasted just as good as you would find them in Florida.

The Pine Island Nursery's website has a nice mango viewer of the varieties they carry. This is a good, reputable mail order nusery. Some good varieties off the top of my head for container growing would be Carrie, Julie, Ice Cream. There are so many new varieties out there now, it's hard to keep up with.

Don't use a container much larger than the roots of the plant. A good, well draining mix will work just fine.


My mango tree did produce some edible fruits this winter. I cannot tell if they taste the same as the ones in the south because I never ate some.

Here's some pictures of my tree:


Thank you Soaht. Thank you

Samuel and Ohiojay, I can't believe it.

Whre do you grow them all winter and do you use lights or natural sun?
Do you feed them?

I am so excited right now. Thank you so much.

Samuel. Is your fruit very sweet and not pulpy? It'doesn't look pulpy at all. It looks mighty juicy and sweet.

What is yours that is fruiting?


1. It grows in the garage with a 1000w metal halide grow light and a couple of cfls. I only feed it with some slow release fertilizer.

2.I do summer them outside.

3. What do you mean by pulpy? It was fiberless and really sweet and juicy. Carrie mangoes tend to be very juicy.

4. It's a carrie mango and I also have a pickering mango that is fruiting right now.

I'll be honest with you. It recently died of root rot :( My mistake! Gave it too much water during fruiting stage. I was also scared in the beginnning to put it in the gritty mix. So I didn't.


I have a GH. Many plants are directly into the ground with bulk of them in containers. No supplemental lighting. Would cost too much to purchase to cover the area correctly and way too expensive to operate.

I do pull some out in the summer. mainly so I can have more unrestricted room while cleaning the glass.

For several years I kept the temps at a minimum of 69-70 degrees. This kept most everything in a state of growth. I now have some rare items that are at the point where they could begin blooming. So I backed the temps to 59 for a few months or so. This gave the plants the needed rest. So now, hopefully these plants will push flowers instead of new growth.

It's now all easy and certainly not a "set it and forget it". It demands a lot of your time and effort. You get humbled quickly and often. You never stop trying to learn something. especially learning from the mistakes you WILL make!

Lots of great resources out there. I don't frequent this forum much. hanging out at our new one. I was only clued into this because someone emailed me and asked that I comment.

Good luck. It is a lot of fun and when a plant sends out its first bloom, it is really something else! But keep in mind there will be disappointments. Plants are going to die for any number of reasons. Many will die for reasons unknown and these are quite frustrating. The hardest to lose are those from stupidity. Boy does this sting. If I could only kick my own butt, I'd be doing it quite a bit.

So seek out all the info you can. Stay away from bare rooted tropical fruit trees for a while.

How To Grow Mango Trees

Here’s a short briefing: Mango trees have been cultivated and grafted for hundreds of years. Grafting was a ‘secret’ in many cultures and tasty mangoes were status symbols for the royalty only. Ancient kings would steal limbs off each others’ mango trees and bribe and kidnap the other kings’ gardeners. Peasants were beheaded for possession of mango fruit or unauthorized cultivation of mango fruit trees. Royalty would try to surpass each other with lavish mango parties and huge gifts of perfect, ripe, delicious mango fruits. Some of today’s Indochinese awesome varieties existed many, many years ago exactly as we have them now.

Mango trees are evergreens. Their leaves make superior mulch.

The civilized grafted mango trees we have now are nothing like the ancient, wild trees whose small fruit tasted like turpentine and had the texture of nylon yarn. The old test of a mango fruit was it’s stringiness, it’s fiber content. You used to judge a mango by how much dental floss it had. The advent of the science of grafting changed all that.

Mango fruit from seeds is never the same as the mother tree’s fruit. So the seed out of a great tasting fruit will likely produce a tree yielding horrible tasting fibrous fruit. The only certain way to be sure you’ll have tasty fruit is to propagate (by grafting, and in some cases cloning) an existing particular, individual tree (DNA-wise) whose quality is proven.

The odds of a seed producing worthwhile fruit are very, very small.

All mango trees grown from any seed are properly called “Wild Mango Trees”.

All good tasting mango varieties are grafted. It’s easy with younger trees to see the graft…just look near the base of the trunk and you can see a scar that circles all the way around the trunk. Older trees have the scar too if they are grafted, it’s just harder to see.

Watch out for grafted trees that have been frozen back to the stump and all the top (good) part of the graft (scion) has died of the freeze and only the rootstock has survived and branched…such trees, if they do live and re-grow, produce very inferior fruit. It is a good citizen’s duty to kill these “fruiting wounded” so that people sampling mangoes for the first time will not taste their unpleasant “free” fruits and form an aversion to all mangoes.

Grafting Is When You Artificially Attach a Tiny Proto-Limb (Bud) of a Desirable Tree to the Lower Trunk of a Similar Tree, Usually a Sapling, Thereby Prolonging the Life and Fruiting Ability of the Desirable Tree. THIS CAN RESULT IN A SINGLE DESIRABLE TREE’S DNA BEING USED FOR AN INDEFINITELY LONG TIME! Like possibly thousands of years!

Sometimes young trees sprout limbs from BELOW the graft’s scar, always kill these limbs because they will produce bad tasting fruits and weaken the good scion above the graft.

Grafting occurs in nature, for example, when two trees growing too close together constantly rub limbs in the wind scraping them both bare at one spot and they both ‘bleed’ sap and when the windy season ends they are still pressed together and grow ‘joined’ together over months into one tree. Grafted. There is this type of ‘joining’ in root systems too.

Most of the mango varieties you find in the supermarket are not ancient. (The best mangoes never make it to a grocery store.) These modern varieties taste great and are resistant to some problems. The newest varieties are often ‘designed’ to taste like other fruits such as coconuts, lemons, vanilla, ice cream etc.

Generally, modern mango tree varieties are superior in every way to the ancient ones.

Except the Nam Doc Mai, a treasured survivor from ancient Siam (Thailand), which politely delivers indescribably delicious fruit, one limb-full at a time, over the course of the year, thus providing a long, manageable supply rather than bestowing a few hundred pounds of mangoes during about six weeks time as is usual with most varieties.

Here are some APPROXIMATE dates of recognition:
Tommy Adkins………..1915

Temperature is very important with mango trees. Cold weather is a major health factor. They die or suffer great damage at 32 F. They go temporarily dormant at about 40 F. So you must learn the normal yearly temperature pattern for where the tree will be.

The idea that there is a “coldhardy” rootstock or cultivar is absurd. All mango trees behave exactly the same way as regards 32 F. They die or suffer great damage.

Here are some cold weather ideas. In some places the threat of frost or freeze is normal only at night for a few nights each year. You can either keep the tree in a container and drag it inside during the hours of frost or freeze or plant it in the ground where you will have to cover it up for only the duration of the frost or freeze. If you cover it be sure to fasten the ‘skirt’ to the ground all around with sod staples so as to trap the ground warmth radiating upward, you can add a light bulb for added warmth or even a little electric space heater…just watch out for rain. Also where the covering tarp/plastic touches the tree the freeze will ‘burn’ it, no big deal usually, but you can get elaborate and build a skeleton frame to stretch the cover over, just remember the wind. Remember to open a vent hole or uncover the mango tree in the morning after temperatures get back above 40 F. You could ‘cook’ it if you forget.

In Northern Florida they used to plant mango trees right up against the South side of the house where the hot water heater was, so the tree kept warm at night. During cold weather, even if there was a killer freeze and some limbs died, the trunk above the graft was still warm and would sprout new limbs and yield delicious fruit in the Spring.

In an emergency, you can heat just the trunk, (it will save the graft and the tree), you will be sacrificing all but one of the scion’s branches. But it will save the life of a grafted tree.

There are several ways to heat it: put hot wet towels, electric heating pads, an electric blanket, or hot water bottles, etc. wrapped around the trunk clear up to a few inches ABOVE the first branch. And put some warm water on the ground near the base of the trunk. Remember you must save at least one limb (small is OK) ABOVE the graft or else the tree is worthless.

It is possible to use sprinklers to spray water onto a tree to save it. BUT you must not stop spraying until the temperature is up to 36 F. Don’t just stop the water at dawn. You can try to divert the flowing water away from the base of the tree and the roots with plastic sheeting, (mango trees like dry winters).

In places where it freezes all night and all day you must keep the tree inside the house near a big South facing window (for light) until the frost threat is over. Lots of light is the main concern. You can phone your local NOAA weather station and they will read you the historically earliest and latest freeze dates in your area so you know about what date to drag it inside. Of course a sunny, heated greenhouse or pool house is nice!

Mango trees like a dry spell for a couple months in the winter.

Water the tree every 3 days for the first month if you plant it in the earth. Then every week for the next 2 months. Then don’t water it any more except for dry spells.

When it’s mature, don’t water very much or fertilize at all during the time when fruit are forming or ripening, you’ll burst the fruit or dilute the flavor.

Don’t let small trees have fruit for 2-4 years. Keep sniping the fruits off when they are golf ball size…fruiting drains the vigor and growth.

Have you ever seen a mango tree with more weight in flowers than tree? Yes, it happens. The excess weight of flowers or fruits can break off limbs and really ruin a tree. You may have to support young trees and trees that have a bumper crop with lumber or ropes. Be creative and over-engineer everything. Don’t ding up the bark, wrap old water hose or panty hose so it’s cushioned where the support touches the tree.

Pruning to remove dangerous excess weight of inflorescences or fruits is OK. Otherwise forget it. You can really mess up the life of a tree fast with just a few uneducated cuts.

Any needed cuts to the tree should be made with sharp clean tools.

Some growers use a hand held one quart propane torch (hardware store) to quickly sterilize the knife or scissors after each cut so as to not spread virus disease.

Don’t burn mango leaves or cuttings, the smoke is toxic. Also don’t allow animals to eat the leaves.

For the first 3 years apply about one level tablespoon of 12-5-9 (scattered) per foot of tree height in fall after all the fruit have been picked. After the tree is three years old start using 4-4-8 with trace elements, apply about 1/4 cup once yearly after all fruit are picked. Fertilizer is mixed with a gallon of warm water and applied to the DAMP soil, not dry, not wet. Apply about a quart daily for four days. Mango trees need less fertilizer than the same area of lawn grass!

A ‘citrus’ type all purpose spray (lots of different brands, but we recommend Exxon 435 soluble oil) is good to spray every month with the Kocide (copper sulfate).

And get yourself a decent sprayer that makes a fine mist.

And get some ‘Kocide’ (brand name for copper sulfate) from a garden shop and spray the trees thoroughly in humid/warm conditions twice a week! Follow the directions on the bag. Add a teaspoonful of dish detergent in each sprayer load to make it stick.

Anthracnose is the condition that spoils the fruit. Look for black dots on the fruit and leaves and the growing tips die curling black. Spray Kocide. Spray twice a week. In Florida or other humid places spray twice a week all year. Don’t let the copper sulfate drip on to the roots, use plastic and rags or paper towels to keep it off the soil over the roots. It is good for the above ground parts only.

Mango trees come from poor, sandy soil with alternating monsoons and droughts. Lots of hot sun. Few nutrients. Since it survives under very harsh conditions you need only keep it from freezing. It’s close cousin is the cashew nut tree.

If your mango tree’s in a pot, check the moisture every week. Stick your finger into the soil, is it damp? Stick your finger into one of the holes around the bottom of the pot, is there moisture at all? Water thoroughly only if dry. The soil should go from very wet to very dry, then back to very wet. And so forth.

Go back and forth from real wet to real dry .

Roots need air just like they need water.

It’s always good to “spin” a potted plant halfway around every month so as to give it sunlight equally all around and help it grow straight.

Not enough means less growth, less flowering and less fruiting.
The more hours of daily direct sunlight…the more tree growth, flowering and fruiting. Also if you reposition the potted tree suddenly, sunburn and leaf dropping can occur because of any change in the amount of light. Sometimes a little leaf dropping isn’t too bad. Acclimation to lighting changes takes weeks and months.

If you want to keep a non-dwarf mango tree small, don’t up-pot it. Make it pot bound.

Just like Bonsai?

Yes, Mango trees are perfect for Bonsai. They were some of the first subjects for the art form. Imagine a six inch tall mango tree that’s 30 years old and has a ripe 3 lb. fruit on it!

(“Julie” is the true dwarf and will get only 8 ft. high. “Cogshall” is the semi-dwarf mango tree and can reach 12 ft. Also there is a new “Hawaiian Dwarf Mango” to try!)

If you are serious about mangoes, then you’ll want to know about proper spacing in a grove. Plant “Keitt” variety, space them about 35 ft. apart in long rows running North and South. Space the rows about 45 ft. apart so as to leave space to drive a tractor pulling a big grove sprayer. “Keitt” fruits get to 4 lbs., ship well, taste terrific, have no fiber at all, are resistant to anthracnose, it’s a huge tall tree, rave, rave.

Go to the library and look up “Mangifera Indica L.” in the card catalogue and in the Reader’s Guide. Join the local Garden Club.

Visit plantations in India, China, Mexico, Pakistan, Indonesia, Thailand, Nigeria, Brazil, Philippines, Haiti and South Africa. Even the Bahamas Islands are now exporting!

Mango fruits cost $1.00 or more each in the supermarkets.

Excuse us, but it needs to be said: there is no such thing as a “mango poop” they are not a laxative.

In many places the mango fruit is prepared and cooked while green and eaten as a carbohydrate.

More mangos are sold on Earth than any other fruit. Any other fruit. Think about it.

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