I recently got a comment on this video where a viewer asks why her sweet potatoes are wilting and have yellow leaves:
So – are these sweet potatoes going to make it?
“Hey David! I am a new gardener (new to veggies, anyway) – and I grew my own slips from an organic sweet potato from Publix, planted them in early June, and have been gleefully watching them grow. (I live in Orlando, BTW.)
I’m starting to freak out a bit because the other day I noticed that I had a few yellow leaves – I pulled them off and didn’t worry. But then I looked out there at about 5:00 and noticed that the entire bed was horribly droopy. It looked like a human had just laid down and rolled around in the bed or something. Then about 20 minutes later, the sky started to cloud over and they stood back up. I’ve been watching them closely and they are fine in the morning and evening, but pretty droopy when the hot sun is on them. I thought it was just the sun and heat, but I started reading online about fusarium wilt.
I’m FREAKING OUT that that’s what it is. More leaves are turning yellow, but I’m still getting new growth and the vast majority of leaves are green. I’m finding some dead, brown leaves underneath, but I don’t see anything wrong with the vine stems. The bed is pretty crowded. (I did a raised bed, 4×4 and about 8″ tall, put thin cardboard down and dirt on top. There was sod under the cardboard.)
Do you have any advice?
I will be crushed if I don’t have any edible sweet potatoes come November. Thank you so much – I have one of your books and I love it, so I’ll be getting more. :)”
More Photographic Evidence
Here are a few more pictures Kerri sent:
Here are the sweet potatoes when all is moist and cool:
And here they are when the sun is beating down:
Normally, I only post garden pictures from readers wearing pink flip-flops, but this time I made an exception.
Why are These Sweet Potatoes Wilting?
Over the many years I’ve grown sweet potatoes, I’ve never had a problem with fusarium wilt or other nasty diseases. They’re easy to grow, particularly in Florida, and so long as you don’t keep growing them in the same place they usually produce a yield.
If the soil was hot sand, they might only give you little roots… but this soil looks very nice. I don’t see any signs of herbicide damage or serious insect problems, either.
The hot sun is tough on plants with tender leaves, such as sweet potatoes and pumpkins. These sweet potatoes are also in a hot microclimate judging by the white wall behind them. If you’ve ever gotten a crazy sunburn while out on the water, you know how reflective surfaces can be tough on your skin. The same is true for plants.
That said, I don’t think the wall is a big deal.
But What About the Yellow Leaves?
If there were a lot of yellow leaves on these plants I would worry. This just looks like the normal growth of sweet potatoes to me. As they age, they drop some of the older leaves and put out new ones.
There was a possibility that they were overwatered (overhead irrigation can cause some rot); however, Kerri wrote me in an email and headed off that possibility:
“I know I’m not supposed to be watering them much – it’s not raining as much as it should this year, so if it doesn’t rain once a week I water them.”
She’s also concerned about the rotten brown spots here and there on the leaves.
In my experience, all this is normal with sweet potatoes, particularly as the summer rolls on. Florida is hot and humid. There are lots of insects, fungi and other things that can damage your sweet potatoes.
Yet this damage is usually overcome by the plants. I’ve had some really awful looking vines produce quite serviceable roots for the table.
My advice: if the spots and yellowing get a lot worse, make up some compost tea with fresh compost some yogurt, kefir, kombucha or other living ferment; stir it up, then pour it or spray it over them all the next day. That often heads off disease issues.
For now, stay the course and keep doing what you’re doing, Kerri. I think you’re going to be fine. If everything looks perfect, you’re probably in a laboratory!
There’s a reason I plug sweet potatoes heavily in my popular book . They usually take a lickin’ and keep on tickin’.
Good luck and let me know how they turn out – and thank you for reading.
Does anyone else see anything I missed? Ever get fusarium wilt on your sweet potatoes? Is there another issue? Let me know in the comments!