How often do you water tomato plants? There’s no one cut-and-dry answer (excuse the pun.)
Your watering plan must take several factors into consideration. For instance, plant to water brand new tomato seedlings on a different schedule than established tomato plants. And you water tomato plants in pots at a different frequency than those in your garden plot. Here are some frequently asked questions and answers about how often to water tomato plants.
Once you place tomato seedlings in their new homes in your garden, water them daily. Give each plant at least a quart of water each day, more if the weather is especially warm.
Established plants get 1-3 inches a week of water (including rainwater) – closer to 1 inch if the weather is cool, closer to 3 inches if temperatures are hot. On average, that works out to 2 gallons of water a week for each plant.
But here’s the tricky part: don’t give them 2 gallons all at once. Plants will dry up in between waterings. Plus, if tomato plants are subject to a deluge, then fruit is likely to overindulge. That means tomato skins cannot expand fast enough to keep up with absorption, leading to cracking. Or inconsistent watering means uneven calcium absorption, leading to blossom end rot.
And quick little sprinklings every day are not the answer either. Light watering keeps roots at the surface of the soil. Tomato plants grow best when they have strong, deep root systems.
Water deeply, about every three or four days, until fruit emerges.
Heat won’t kill your tomato plants if they get water. But be aware that temperatures consistently higher than 90ºF and nights consistently above 75ºF create extra stress. Plants abandon their work to produce blossoms and fruit and simply move into survival mode.
While deep watering a couple of times a week is typically best for tomato plants, a heat wave is not a typical situation. During hot weather, water your tomato plants daily, but give them less volume. You can return to twice-weekly deep soakings when the temperature breaks.
And when weather is hot, consider providing relief for plants with shade cloth, particularly from 10 AM to 2 PM during the heat of the day.
It’s not unusual to have to water your tomato containers every day, regardless of temperatures. Tomatoes in pots have limited space in which to spread their roots. Plan to give your established tomato plant a gallon of water a day – more during the heat of the summer.
When your tomato seeds are preparing to sprout – and just after tomato seedlings push through the soil and have one or two sets of leaves – misting is okay. But beyond a seedling’s first week or two of life, do not mist them.
Misting broadcasts water on a tomato plant’s leaves, stems, and fruit. That opens up all kinds of opportunities for fungi and diseases to spread. Avoid misting. The best way to water tomato plants is to use drip irrigation or a garden hose at the base of the plant.
Can you overwater tomato plants? Yes. Tomatoes, like most veggies in the garden, need an inch of water a week and up to 3 inches if it’s particularly hot. That translates into about two gallons per plant. And don’t forget – that includes rainfall.
But overwatering or quick watering means excess liquid pools on the surfaces. Soggy soil chokes your tomato’s roots and prevents them from getting oxygen. Bottom line, over watering drowns your tomatoes.
You’ll recognize overwatered tomato plants by yellowing stems and leaves, which may develop brown edges. As for the fruit, the interior of a tomato expands quickly when it takes in water but the outer skin can’t keep up. Too much water delivered too quickly leads to tomato cracks. And if you suspect you’re overwatering, take a peek under the soil. A healthy tomato plant’s roots are pale, but an overwatered tomato plant has slimy, darkening roots.
If your plant is overwatered, you can gently lift it from its position in the garden (being careful to gather the root ball and surrounding soil) and move it to a container or a protected area. Let the roots dry out and then replant.
And readjust your watering schedule.
When a frost or freeze puts an end to your tomato season, you can put away the watering hose, too.
More on watering tomato plants
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