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How much water does lettuce need?

Gardeners hands harvesting a large lettuce head from a lettuce garden bed

Growing lettuce in your garden is nearly instantly gratifying as it can grow to maturity in as little as 30 days. Lettuce is relatively low maintenance, and the varieties you can grow are limitless. Because of these and many more reasons, many gardeners love to add lettuce to their spring and fall crops. While lettuce doesn’t require constant attention, it does however have pretty specific water requirements. Lettuce is made up of almost entirely water, so too little, or too much water can be catastrophic for your lettuce crop. So just how much water does lettuce need, and what is the best way to water your lettuce garden? Keep reading to find out!

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How much water does lettuce need?

You should give your lettuce plants around 1 to 2 inches of water per week[3], but this can fluctuate depending on what kind of soil you’re using, what climate you live in, and what season you are planting. During the hot weather of the summer months, you should water your lettuce garden more frequently, being sure that the water reaches 6 inches deep into the soil. As with most plants, the soil when watering should be sufficiently moist, but never sopping wet. If your soil is still very damp the next time you go to water, you may be able to hold off on watering for another day. If you’re unsure about the moistness of the soil beneath the surface, you can use a moisture meter to check if the soil is still damp closer to the root. You can also use your finger to test the amount of water in the soil. If your finger comes up damp with wet soil clinging to it, you can probably stretch a bit more time until your next watering. 

Most lettuce plants can be watered once or twice a week, with about 1-2 inches of water. If your area receives rain, always check the soil before watering to determine if the plants really need it. If your area is scheduled for multiple days of heavy rain, this can quite easily drown out your lettuce plants, causing root rot and eventual death. To protect your plants from the rain set up an umbrella, or cover them with plastic bags until the rain subsides. As soon as the weather clears up uncover them so they can get plenty of sunlight and the excess water can evaporate. 

Overhead view of gardeners hands planting immature lettuce plants into the soil with surrounding lettuce plants

How much water do lettuce seedlings need?

Lettuce seeds and seedlings will require different watering quantities and methods. If you are growing lettuce from seeds, you should start them in a seedling tray indoors. Lettuce seeds should be planted no more than 1/8 of an inch deep in the soil [3]. If they are planted too deeply they can be subject to drowning and inadequate sunlight, causing them to fail to germinate. Because lettuce seeds are planted so shallowly, they are at risk of being dislodged from the water pressure caused by a hose or watering can. It’s best to use a more gentle watering system for seedlings, like a mist bottle. This will keep your seedlings moist, but not disrupt their germination by keeping them firmly planted in the soil. 

Lettuce seedlings require constantly moist soil, and therefore frequent watering is needed. You should check the moisture of the soil every day. If the soil on the surface is beginning to dry, it’s time to water. Depending on your climate, this could mean watering your seedlings every day with your misting bottle. Heavily mist your seedlings being sure that the soil becomes moist but not sopping wet. If the soil is too wet this can cause your seedlings to drown and die or cause mold growth.

What is the best way to water lettuce?

Lettuce is made up of about 96% water[2], so it goes without saying that water is pretty important in the growth of healthy lettuce plants. You should water your lettuce plants once or twice a week, or every 3-4 days depending on the dampness of the soil. If the weather is particularly hot, you should water more frequently. Lettuce plants have quite shallow root systems, so they require a bit more water than other plants to make sure the surface of the soil stays moist. So you can wait a few days between watering, but be sure they are getting enough when you do. Drip irrigation is also a great option for lettuce in the garden as it will keep the soil constantly moist without drowning out the roots. 

Because lettuce leaves are extremely delicate, it’s important to not water directly on top of them. Excess water on the leaves can them to become slimy and rot, which can spread to the rest of the plant. If leaf rot occurs, you should remove them immediately.  When watering, focus on the soil surrounding the lettuce head instead of letting the water shower on top of the plant. 

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Tips for caring for lettuce plants

How much sun does lettuce need?

Lettuce seedlings require plenty of sun to grow properly. If you are growing lettuce from seed, you should place your seeds in a location that receives 14 to 16 hours of sunlight each day[5]. Mature lettuce plants can thrive in less than 14 hours of sun each day, but still require at least 6 hours of sun per day. If you live in a hot climate consider planting your lettuce in an area that gets partial shade, as lettuce prefers cooler weather.

What is the best kind of soil for lettuce?

Growing lettuce from seeds can be done in a high-quality potting mix or potting mix designed specifically for growing lettuce. A soil that is able to retain moisture is best as it keeps the seeds moist so they can properly germinate.

Lettuce planted in the garden “grows best in loose, cool soil with good drainage”[1] to prevent a buildup of excess water while also holding on to moisture necessary for the roots of your lettuce plants. Adding compost to your soil will help with drainage and also provide more essential nutrients. Lettuce plants like slightly acidic soil, with a pH of around 6[1]. Adding lime to your soil will help bring up the pH level, and you can use a pH testing kit to make sure you don’t go overboard.

How much water does lettuce need?

Lettuce needs constantly moist soil, but never wet or soggy soil. If your soil is too wet it can lead to root rot, your plant wilting, or even the death of your plants. Underwatering is also a no-no as it can cause bitter leaves, and dry brittle plants, and eventually can kill your lettuce as well. You should water your lettuce plants at the very least once a week, or whenever the soil appears dry on the surface. Depending on the soil, and climate you may need to water more frequently. Test your soil with a moisture meter, or with your finger to make sure the soil is damp 6 inches below the surface. 

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What is the best fertilizer for lettuce?

Lettuce plants do their best in nutrient-rich soil and will produce the best-tasting leaves when grown in it. You can add extra nutrients to your soil by using compost and fertilizer. Add compost or a fertilizer that is high in nitrogen to the soil 3 weeks after planting[4]. This will help grow strong and delicious lettuce. 

How do you avoid overwatering lettuce?

Overwatering plants is one of the most common gardening mistakes, especially in novice gardeners. Lettuce is a low-maintenance crop and only requires watering once or twice a week. Because of this, we overcompensate by overwatering, as we feel there is something else we could be doing to get the most out of our crop. The best way to avoid overwatering is by analyzing the state of your garden before watering. If the surface of the soil is dry, you should water it. If the surface of the soil is still slightly damp, test the soil below the surface using a moisture meter, or your finger and then determine if watering is necessary. Overwatering can be devastating for lettuce, so be sure to wait for your plants to tell you what they need.


Articles Sources: 

  1. Gilmour. “Growing Lush, Green, Crisp, Lettuce” 
  2. Plantophiles. “How Much Water Does Lettuce Need – Let Us Explain!
  3. SFGATE. “How to Water Lettuce
  4. The Spruce. “How to Grow Lettuce
  5. Urban Cultivator. “How To Grow Lettuce Indoors