homepage logo

Garden Help Desk: Preventing your potatoes from growing rough skin

By USU Extension - | Sep 24, 2022

Courtesy Meredith Seaver

It's not unusual for potatoes to have some blemishes on the skin. These potatoes are still perfectly safe to cook and eat, even though the skins were damaged by chronically wet soil.

We just harvested our potatoes. Most of them have really rough skin. How can I prevent that next year?

I’m going to assume that you didn’t see anything wrong with your potatoes except for the rough skin. If you noticed other things — dark, soft spots, oozing, etc. — you’ll want to send us photos and more details about what you see.

Rough or scaly skin on potatoes is common with potatoes that have been overwatered. You’re familiar with the eyes on potato skins, but the skin on a potato also has pores, called lenticels. These lenticels can swell, and the skin can blister when the growing conditions are kept wet. This can cause the rough texture you found with your potatoes.

Next year, plant your potatoes in well-drained soil. Potatoes take up moisture from the top 12 inches of the soil, so water deeply, but don’t water so frequently that the soil below the surface stays wet. Check the soil moisture a few inches down into the soil if you’re not sure whether it’s time to water. It won’t take long before you have a good idea of what the right watering schedule is for your potatoes in your garden soil. A layer of mulch over the soil will help keep the soil moisture even without the risk of having soggy soil.

The rough skin doesn’t affect the quality of the potatoes. They’ll still be delicious, so go ahead and enjoy them.

Courtesy Meredith Seaver

Potatoes that grow in wet soils can develop a rough texture on their skins because the chronic moisture can cause the skin to blister.

My tomatoes were doing pretty good, but then yesterday when I picked some, they had split skin down the sides of the tomatoes. What happened?

Tomatoes can develop cracks over time as they grow. The cracks may be concentric circles around the stem, or they may radiate out from the stem like rays. This can happen any time during a tomato’s development but it’s more common on tomatoes that are nearing maturity. Cracks may continue to expand during the season. The cracking happens because the tomato grows or expands faster than the skin can expand. Since the splits on your tomatoes happened suddenly, and the fruits were looking great and nearly ripe, the most likely cause is the rain we had last week. Your tomatoes were mature, and the peels were probably toughening up. Then some parts of Utah County had a day of pretty nice rainfall. The extra moisture caused the tomato fruit to expand faster than the skin could expand, causing the skin to split.

There isn’t much you can do about episodes of wet weather, but avoiding swings between wet soil and very dry soil with your garden irrigation will help you avoid cracked fruits and split skins at other times. Deep but not frequent watering is what your tomato plants need and a light layer of compost or some other mulch will help even out the moisture.

Avoid over-pruning your vines or pruning too early in the season, as that can expose the tomato fruits to direct sun and heat. Also, weed and cultivate carefully when you’re near your tomato vines to avoid damaging the roots.

There are tomato varieties are more likely to experience cracking, so choosing crack resistant varieties will improve the quality of your tomato harvest. Look for crack-resistance in seed catalog descriptions.

Courtesy Meredith Seaver

Swings between wet and dry soil can cause radial or circular cracking near the tomato stem. A sudden increase in soil moisture can also cause the skin on a ripe tomato to split.

You don’t necessarily need to throw those tomatoes with split skins into your compost pile. If you find fully ripe tomatoes while the splits are fresh, they’ll be perfectly fine to eat. After they’ve been on the vine for a few days, fungi can begin to grow in the juicy flesh of ripe tomatoes where the skin split, and you’ll want to discard those. The cracks that form in tomatoes that aren’t fully ripe may harden and “protect” the flesh underneath. These parts of a tomato can be trimmed away so that the tomato can be used.

When a ripe tomato gets a split in the skin, mold can begin to grow in the moist flesh of the fruit.


Join thousands already receiving our daily newsletter.

I'm interested in (please check all that apply)