Tomatoes have a reputation for being thirsty plants, appreciating regular watering and consistently moist soil. However, there is such a thing as overwatered tomatoes, leading to serious root issues and potential plant death.
Overwatering is a common tomato plant mistake, resulting in a range of signs and symptoms to watch out for. Not all are caused exclusively by overwatering, but assessing the soil and your watering routine will tell you whether this problem is something you need to worry about.
Watch out for these seven signs and act as soon as possible. The quicker you allow the soil to dry out and adjust your watering schedule in the future, the sooner you can secure your harvest.
Use raised beds for improved drainage and to avoid waterlogging.
Before you look to your tomato plant for signs of struggle, it’s always best to start by investigating the foundation of plant health – the soil.
If you water when the soil is still saturated, it will likely pool around the base of the plant rather than draining away. This pooling indicates the soil is waterlogged, causing overwatered tomatoes and a high risk of rot.
If you live in a summer rainfall area, this may be no fault of your own. Excessive rain can also lead to waterlogged soil if your tomatoes are planted in the incorrect soil type or in a low-lying area. Raised beds are one way to improve drainage in these cases, preventing any potential waterlogging.
When you notice waterlogging, allow the soil to dry out before watering again and adjust your routine. If soil texture is the problem, amend with compost or consider transplanting into raised beds for better root health.
Both overwatering and underwatering can cause drooping tomato plant leaves due to root health issues.
As soon as gardeners notice drooping leaves on any plant, lack of moisture is the first concern to come to mind. There is plenty of logic to this thought – wilting is the first sign of underwatering in tomato plants. But it’s not the only potential cause.
As contradictory as it may seem, overwatering can also cause leaves to droop and wilt, just like underwatering can. However, the signs are slightly different, allowing you to determine the primary culprit. While underwatered foliage will be dry and crispy, overwatered tomato plants will usually have soft and mushy leaves or stems.
The issue lies in root health. When you overwater, you limit the amount of airflow around the roots, essentially suffocating them. The excess moisture can encourage fungal growth that spreads throughout the plant, killing tissues and impacting moisture uptake.
Unhealthy roots struggle to transport water and nutrients to parts of the plant that need it, leading to drooping leaves. Allowing the soil to dry out and changing your watering routine may fix the problem, but if wilting continues, you may have a bad case of root rot.
Downward-curled leaves may result from overwatering, indicating root stress that can harm plant growth and fruit production.
Curling tomato leaves can induce panic in tomato growers, but the problem is more common than you may think. There are many potential causes for curling leaves, including overwatering.
Curling leaves are an indication of stress in your tomato plants. A stressed plant will struggle to grow and produce fruit, so quick action is key.
In the case of overwatering, the stress relates to the roots. The lack of airflow and potential root rot have ripple effects throughout the rest of the plant. The leaves will typically curl downwards and under rather than upwards as they would when underwatered or overheated, indicating a potential root issue.
Leave the soil to dry out for a few days to see if the leaves return to normal. If they don’t, fungal disease may be spreading. If you’re growing several tomato plants, it’s best to discard affected ones that do not recover to stop the issue from spreading to healthy and unharmed plants.
Yellowing tomato leaves or blackened leaves can signal watering issues, often related to fungal diseases.
When previously lush and green tomato leaves begin to change color, they’re trying to tell you something is wrong. Although there are many potential culprits, the prime suspect of discoloration is overwatered tomatoes.
Yellowing leaves are the most common issue, indicating a problem with chlorophyll production. When root health is negatively impacted by overwatering, the roots struggle to perform the necessary functions to keep the plant alive. Unable to transport moisture and nutrients around the plant, the leaves begin to turn yellow and may drop off the plant.
Occurring far less often, black leaves are another potential sign of overwatering. Excess moisture around the roots can encourage fungal disease that spreads throughout the plant, including in the leaves. Black spots don’t always indicate a watering issue, but it’s important to check the soil conditions if you notice this troubling sign.
As soon as you spot any discoloration in your tomato plants, it’s time to do some detective work. Assess the soil and root health, along with previous rainfall and your watering schedule, to check whether overwatering may be the cause. If so, hold off to let the soil dry out for a few days before watering again.
Fungi in waterlogged soil can devastate tomato plants.
Root rot is an incredibly damaging disease that can quickly ruin your season’s tomato harvest if not managed.
Various fungi cause root rot, including Pythium and, more commonly, Phytophthora. If they spread throughout the roots, the damage will quickly kill off your tomatoes and possibly whatever you plant in that spot the following season.
The primary cause of root rot is waterlogged soil, typically due to overwatering. The lack of oxygen and excess moisture creates the perfect environment for fungus to spread, killing the roots and turning them to mush.
Since root rot occurs under the soil, it can be tough to identify. You’ll usually notice other signs of struggle first, like wilting and yellowing leaves. Also, check the area where the stem meets the soil line. Rot can spread quickly from the roots up the stem, leaving it soft and mushy.
Unfortunately, once root rot has taken hold, it’s difficult to eliminate. If your tomatoes are still young, you can lift them, trim the affected roots, and transplant them into fresh soil to continue growing. But older plants are usually better discarded to stop the issue from getting out of hand.
The fungus that causes root rot will also remain in the soil, so it’s best to avoid planting anything in the same spot for a while. Switch to raised beds or containers to have complete control over soil conditions.
Blossom End Rot
Blossom end rot is caused by calcium deficiency, hindering calcium transportation to the fruits.
Watching fruits develop on your tomato plants is an exciting process. But that excitement can be cut short by the sight of sunken and brown spots on the base of the fruits.
This common tomato problem is known as blossom end rot – a physiological disorder rather than a disease. It is caused by a lack of calcium in the fruits that impacts development as the young tomatoes grow.
Since blossom end rot is caused by calcium deficiency, gardeners often assume the solution is to add more calcium to the soil. But that’s not always the case. More often, the issue is not with calcium presence in the soil but with the root’s ability to draw up calcium, leading to deficiencies within the plant.
That’s where we come back to overwatering. Excess moisture leads to root damage that impacts the transportation of moisture and nutrients around the plant. If the roots can’t move calcium from the soil to the fruits as they grow, they will eventually develop blossom end rot.
Affected fruits, unfortunately, won’t return to normal if you fix the overwatering problem. You can still eat the tomatoes, but it’s best to cut off the problematic areas first. Adjust your watering schedule to ensure later-season tomatoes are problem-free.
Overwatering or heavy rain can cause cracked fruit, impacting appearance, flavor, and pest vulnerability.
The final sign of overwatering also appears in the fruits, particularly towards the end of the season when the last of the fruits start to ripen.
When the plant receives too much moisture at one time, the pressure can cause the developing fruits to crack. Not only does this impact look, but it also reduces flavor and makes the fruits more vulnerable to pest damage.
Cracked fruit isn’t always caused by overwatering. It’s often the result of unexpected heavy rain, overwhelming the plants when the fruits are almost ready for picking. If heavy rain is forecasted at the season’s end, gardeners often prefer to pick their tomatoes early and ripen indoors than risk a ruined harvest.
If you notice cracked fruit and haven’t had any issues with rain, it’s time to look at your watering routine. Although it’s vital to keep watering to help the plant produce juicy fruits, overdoing it at this point in the season can have the opposite effect on plant health and tomato taste.
The key is consistency. As long as you maintain a consistent moisture level in the soil, watering only when needed rather than on a strict schedule, you can keep your fruits pristine and crack-free.
Tomatoes may love moisture, but too much will do far more harm than good. Take action as soon as you notice any of these signs, maintaining root health and securing a strong harvest at the end of summer.