How To Prevent Sunburned Plant Leaves

Sunburned plant leaves… seriously?!

This past weekend we had what I’ll call “a whole lotta weather.” It was in the high temperatures of 84 and then it was 35, and there was a little bit of rain and a lot of clouds and a whole lot of sun. 

So, there was at least 2 seasons worth of weather in one weekend!

How To Prevent Tomato Leaf Sunburn (and other plants)

It’s been about 2 weeks since I’ve planted the majority of my vegetable seedlings in my various gardens.  I didn’t plant them as seeds.

I bought them from my local nursery as seedlings and planted them in my garden a couple of weeks ago.  The weather has been a pretty nice 65 – 72 degrees, except for the weekend, of course.

After this weekend of “a whole lotta weather,” I noticed that my cherry tomato plants that I have in a planter on the front porch had yellow leaves that looked like someone had spray-painted them with gold paint, and I couldn’t figure out what was going on.

I never knew it would be a tomato leaf sunburn and need sunburned plant care. I was thinking “can leaves burn in the sun?”.

Common Cause Of Tomato Leaf Problems

• Leaf Curl or Curly Top Virus has similar symptoms. It also causes yellow leaves or yellow areas.
• Tobacco Mosaic Virus
• Early Blight can also cause yellow, black, or dark brown spots.
• Late Blight will have dark spots and browned leaves or areas with the edges of the leaves and leaf margins gray-green.
• Septoria Leaf Spot is a fungal infection or disease that usually appears on the older leaves after the first fruit sets.
• Fusarium Wilt or verticillium wilt diseases begin as the yellowing of older leaves and leaf veins. With Fusarium crown rot, the leaves often turn brown or black and eventually wilt.
• Bacterial leaf scorch is one of the most common infectious diseases that form small spots that appear on the leaves of the tomato plant. These spots will be brown in the center, surrounded by a yellow ring.

While you do need direct sunlight to have ripe fruit, too much sunlight beaming down on the fruit during low humidity can cause the fruit to burn and leave you with sunburnt leaves.

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Tomato Fruit Problems Due to Hot Weather

• Tomato crop tops with yellow or green shoulders and affected areas that may take up the entire shoulder can be caused by too much direct sun exposure. So you need to be extra careful of heat stress in early summer or late summer.
• You may not think of insect pests like stink bugs as a vegetable plant major problem, but when you expose fruit to them, they cause spots and internal damage due to their eating the plant and fruit. Adults are shield-shaped and brown or green, with red, pink, or yellow markings. They release an offensive odor when handled. 
• Blossom end rot: The cause is thought to be a combination of cold temperatures or intense sunlight during blossom set and fluctuations in the flow of water supply.

Sunburned Cherry Tomato Leaves

I asked my neighbors if they knew because, as I’ve told you before, they can throw anything in their yard. It will grow.  They thought it was mud and dirt on the vegetable leaves due to the “world of weather” we had.

But, it wasn’t until I started seeing several sun scorched leaves on other old and young plants that I decided to take some pictures and look it up online.

Apparently, many of my vegetable and herb plants got sunburned!  Who knew?! 

Well… Google… lol  Apparently, plant burnt by sun happens when you put seedlings out, and they haven’t had time to harden off.   (This is most common on green fruit like green tomatoes).

What that means is when you put the seedlings out, they’re still just babies, and they haven’t really had time to adjust to any kind of weather. It can leave you with a sunburn plant and sunburn tomato leaves showing on the green tissue.

Inappropriate or low soil moisture or anything that makes a plant’s root system unhealthy causes root damage and prevents old and new plants from absorbing adequate or sufficient water, which may contribute to plant sunburn or leaf scorch.

Plants vary a lot in their tolerance of growing conditions. The selective breeding of varieties capable of withstanding particular climates forms an important part of agriculture and horticulture.

Plants adapt to changes in climate on their own to some extent. Part of the work of nursery growers of plants consists of cold hardening, or hardening off their plants, to prepare them for likely conditions in later life. 

Wikipedia

Now, I will also say that many of my herb and vegetable plants had old black and young leaves on them, as well, because it got so cold that some of them kind of froze. 

I told you it was CRAZY we had a lot of cold and dry weather! Making it definitely an unfavorable environment for any plants, much less babies. 

So, there my lower leaves were frozen, and I had sunburnt plant leaves on top of the plant.  They were quite a sight.

How To Help Sunburned Plants And Prevent Sunburned Leaves

So, keep this in mind when you’re putting out your seedlings.  You need to treat them more cautiously or carefully than you would plants that have been growing for a while. 

Think of the environmental factors. Try putting them out in partial shade for 1/2 an hour day one, then slowly over 7 days move them to more and more sunny areas and more like their environment will be, also give them some drying winds if they’re not being blown around. 

Maybe a small breeze with a fan if you don’t have much high winds.  In Texas, the dry winds are crazy and are always blowing and often very strong. 

These extra measures should help to prevent sunburned plant’s leaves in your garden.

Another easy and effective way to “Harden Off” your plants is to find 3-4 overcast days in a row and move them out and leave them and when the sun comes back around day 4 – they should be ready.

I put mine in the shade for 4 days and then move them to the greenhouse until I have time to plant.

Choose one of the above methods so you don’t end up with sunburn leaves or tomato plant sunburn like me.

Watch this video as I explain more about Hardening off your seedlings:

All of that helps them “harden off” and get used to the weather conditions and environmental stress so that when you put them outside and the weather hits, hopefully not as it hit for me, it will be okay for them.

For how to heal sunburned plants, this is how I handled the situation:   I made sure that all the plants had plenty of soil water, so they didn’t have to stress over their lack of water and drought conditions.

Or from having this frozen/sunburned stuff happening simultaneously like the tomato sunburn leaves I had.

Then, I cut off most all of the sunburned leaves and the dead tissue, as my tomatoes are now beginning to have fruit on them.

I don’t want them to be working hard to try and send nutrients to the leaves that are burnt and are not going to get better, so I just cut all those off so that they could concentrate on the fruit they’re growing.

That’s how to save sunburned tomato plants. or at least how I saved mine.

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But watch out for new growth or new leaves.

The plant leaves are soft and quite likely to have leaf burn. It’s a good idea to use a shade cloth to prevent leaf sunburn to the leaf tissue.

Keep that in mind if you have this weird look to your leaves or scorch symptoms.

You had “a whole lotta weather,” as we had, then maybe you didn’t let them harden off before you put them out, or your plant roots or tree roots aren’t getting enough water or have drought stress from improper watering, and now you have sunburn on leaves and leaf drop.  

You can always cut a leaf off and take it into your local nursery or the place you trust about plants and show them and see if they can help you figure out if it’s something else or if your sunburn plants have become like my sunburned tomato leaves.

Frequently Added Questions About Sunburned Plants:

How do you fix a sunburned Money Tree?

The way to fix a sunburned Money tree is the same as the plants we discussed. Move them to the shade, cut off scorched and burned leaves, water well.

Can tomatoes get sunburned?

Tomatoes can get sunburned, especially if they are young and have not been hardened off well.

Can Basil get sunburned?

Yes, Basil can get sunburned just like other plants if not hardened off well.

Can indoor plants get sunburned?

Yes, indoor plants can get sunburned, too.

What to do with sunburned leaves?

What you do with sunburned leaves is cut them off to allow the plant to concentrate on healing.

What do sunburned leaves look like?

Sunburned leaves look like they have been spray painted gold, they look thin and leathery.

Should I cut off sunburned leaves?

You can cut off sunburned leaves to help the plant focus its energy on recovering instead of trying to fix the leaves that are going to further stress the plant.

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You can also find gardening products I use in my videos here <---

I now have an Amazon Influencer’s storefront. I put the products I use, in my posts and Youtube Gardening videos, there. Shopping there is free and the site gets a percentage of sales. Thanks!

You can go to my storefront using this secure link <----

If you need seeds, this is the company I use <--- and if you use code: farmer1 at checkout, you'll get 10% off your order!