Hydroponic Lettuce Care Infographic

Hydroponic lettuce is the best plant to grow in your home garden or commercially as it is easy to achieve high yields as long as you provide proper care.

Although this green, crispy vegetable plant is easy to grow, knowing the correct ways of parenting it is crucial.

The lettuce can also be called Lactuca sativa and is widely used for making salads.

This article will groom you into being an expert in growing lettuce as a hydroponic all year round, with significantly minimum chances of failure.

What Is Hydroponic Lettuce?

The hydroponic lettuce is a water-grown plant that can achieve a height as well as the leaf’s width of 12 inches. The plant has many varieties including Butterhead and Romaine. The Butterhead is one of the best lettuce for hydroponics. The Bibb lettuce and Boston are Butterhead types.

Hydroponic Lettuce Care

Proper care should be exercised when growing hydroponic lettuce, even though it is considered an easy-to-care plant. Make sure all the growing conditions needed for your hydroponic lettuce to grow vigorously are met.

Effective plant care can benefit you by being saved from exorbitant hydroponic lettuce price in the market as you will be enjoying your quality produce.

– Water Requirements

You should add more nutrient solution once you notice that it has evaporated and it’s now too little for your hydroponic lettuce to grow well. After every two to three weeks, consider changing the whole solution and replacing it with a fresh one. 

The solution can be used for watering your house or garden plants once your hydroponic lettuce is harvested. You should have a suitable hydroponic kit so that you can set up the system that allows you to water and feed your hydroponic lettuce.

Many hydroponic systems can be used to irrigate your lettuce but we do not recommend deep water culture. Using this method for growing hydroponic lettuce can risk it being affected by diseases.

The Nutrient Film Technique (NFT), as well as the Ebb and Flow (Flood and Drain), can be used for your lettuce to get nourished perfectly. The film technique system has a reservoir at the bottom that is attached to the water flow and fills tubes to allow water to circulate along the plant roots’ base for absorption.

The fill and flow tubes facilitate the movement of water to the top, piped chamber that holds your hydroponic lettuce. The pipes should have holes where the roots will hang down to absorb the circulating water in the pipes and the reservoir as it is pumped continuously. 

The Flood and Drain technique is also a popular system that involves the use of a growing chamber, reservoir, and pump as well. On this one, the water is pumped once in large quantities to the top chamber and drained back into the reservoir once your hydroponic lettuce adequately absorbs it.

– Light Requirements

Hydroponic lettuces in a hydroponic pipeHydroponic lettuce requires 10 to 14 hours of low to moderate light every day for it to grow well. Too much sun can cause the hydroponic lettuce’s leaves to become bitter and too little light can slow down the plant’s growth rate. 

Low light can also affect the color of your hydroponic lettuce, especially the darker red leaf varieties. So if you are growing this type of lettuce, consider buying a grow light.

You should consider buying LED lights as they have a timer for adjustments whenever there is a need to do so. The LED lights are also found in different sizes and shapes to cater to everyone’s choice and level of affordability. 

Additionally, choose the grow lights that provide the full, blue spectrum so that your hydroponic lettuce can absorb more light. The LED lights are also crucial as they do not burn the leaves of your hydroponic lettuce.

– Soil Requirements

Hydroponic lettuce is grown in water so they do well without soil but it should not be completely barren. You should provide your Hydroponic lettuce with the growing medium that can replace the soil like the phenolic foam, coconut fiber, pine bark shavings, sawdust, or stone wool.

The medium can also be used if you want to germinate the seeds. Please note that using the growing medium can risk your hydroponic lettuce being infected by root rot. 

Diseases are the main reason the lettuce is being grown as a hydroponic. Once the medium becomes too wet, it can become impermeable as it quickly loses its structure. The plants can then fail to breathe as they need oxygen to survive.

– Temperature Requirements

Different types of lettuce grow well in cooler temperatures between 68 and 75 degrees Fahrenheit during the day and 60 to 65 degrees Fahrenheit at night. Do not expose your hydroponic lettuce to high temperatures as they promote flowering, which causes the plant leaves to become bitter. 

That’s why you should grow your lettuce indoors to avoid bolting, temperatures below 59 degrees Fahrenheit are not ideal for the plant roots. Exposing your hydroponic lettuce to such conditions can cause the roots not to be able to absorb nutrients and water for the plant.

– Humidity Requirements

Hydroponic lettuce prefers humidity levels of around 60 percent. Very high humidity levels can cause stunted growth as your hydroponic lettuce will be deprived of oxygen. Humidity levels that are too low can also cause the hydroponic lettuce leaves to curl inward as a way of protecting themselves from cold and hot air. 

Note that too low humidity is a sign of insufficient moisture around the plant and this can cause dehydration. Make sure you maintain the humidity levels required so that you can produce healthy and tasty lettuce.

– Fertilizing Requirements

Hydroponic lettuce should be supplied with high-quality nutrient solutions for it to survive and be healthy. You should supplement the hydroponic lettuce nutrients by adding fertilizers as the plant requires more nitrogen and potassium. 

These two nutrients encourage the growth of leaves, reduce the chances of wilting, and improve the plant structure. We recommend that you use the fertilizer called Lettuce Greens and Herbs hydroponic mix as it has the most needed micro and macronutrients.

The fertilizer is in powder form and you should mix two pounds of it with water to come up with 128 gallons of nutrient solution. Do not apply too much fertilizer as it can negatively affect the flavor and taste of your hydroponic lettuce.


Lettuce hydroponic grows quickly that it can reach maturity within a month. Growing lettuce hydroponically increases the chances of you a bumper harvest.

– How to Harvest Hydroponic Lettuce

Harvesting can start at three weeks but can be completed between 45 to 85 days. You can harvest individual leaves that you should use immediately as they cannot be stored for future use. 

Most hydroponic lettuce types are harvested by removing the mature, outer leaves to allow for continuity in plant growth. The inner leaves will have enough space to grow also until they reach maturity.

Individual leaf harvesting makes it possible for you to enjoy your hydroponic lettuce sooner unlike waiting for at least six weeks for the whole head to be harvested. Removing individual leaves make it possible for your hydroponic lettuce to regrow. 

If you remove all the leaves on the head and continue providing it with all the requirements that are necessary for growth, it can start to grow again. Furthermore, you can increase lettuce production without having to replant, either by germinating the lettuce seeds or using saplings.

Harvesting can also be done by removing the entire hydroponic lettuce head. Most hydroponic lettuce from grocery store will be in a head form as it can stay longer that way. By harvesting the head, you either remove the root system part or cut all the leaves at once from the plant base.

– How to Store

You can only store your hydroponic lettuce at home in the fridge if you cut the whole head. It can stay longer also if you wrap it in a damp paper towel. Additionally, you can also put the harvested hydroponic lettuce’s head in a bowl filled with water for it to remain fresh for an extended period of time. Allow only the base of the head to sit in water so that it will not get bad quickly.

Keeping your plant fresh is crucial for you to enjoy all the hydroponic lettuce benefits. The plant contains lutein, B-carotene, and folate which are nutritious components of your diet. Certain lettuce types like dark or red ones contain cholesterol-lowering, anti-inflammatory, and anti-diabetic qualities.

Common Problems

Growing hydroponic lettuce can save you the stress of having to regularly check for pests and diseases. The soil is a habitat for many pests so growing your lettuce in water reduces the risk of plant infection. However, you will still need to be on the lookout for the following hydroponic lettuce problems.

– Water Molds

Water molds such as phytophthora or pythium can affect the hydroponic lettuce as they are spread by water. These pathogens are waterborne so once one plant is attacked, none of the hydroponic lettuce will be left uninfected. The pathogens are carried around to all lettuce plants when the water is circulating in pipes.

Water molds can be difficult to get rid of as there are no fungicides that can control this disease. If your lettuce is infected, the chances of losing every single plant are very high. 

Remember that you should protect your lettuce from being infected by sterilizing all the nutrient source systems and tools that are used on seedlings, as well as growing and mature plants. Disinfecting your lettuce plants will hinder the development and spread of the disease.

– Powdery and Downy Mildew

The powdery and downy mildew favors warm, moist, and contained areas. Hence, the lettuce that is grown in soil is mostly infected as the plant leaves are sometimes wet due to overhead irrigation.

Even when you water your hydroponic lettuce from below, make sure the spaces between the lettuces allow free air circulation. Additionally, leave space for excess moisture to evaporate easily so that you won’t create the conditions that are ideal for powdery and downy mildew.

Look for powdery mildew infection on the upper sides of the leaves, mostly in summer. You will see white powder in a circular shape on the leaves of your hydroponic lettuce.

The downy mild is usually found in winter on the undersides of the leaves. Once your hydroponic lettuce is infected, the leaves will turn yellow or light green having the powdery fungal growth on the under part of the foliage.

The leaves may also fall and if not treated, they may become brown and die. The disease can be controlled using the recommended fungicides if detected early.

Hydroponic Lettuce disease

– Algae

The algae thrive well in the growing solution as there are all the nutrients and water needed for it to survive. The place where you grow hydroponic lettuce is always humid, which makes it a good target for algae.

Besides these three conditions, the algae also need more sunlight to develop. You can easily see that the solution system is infected with algae when the water becomes green, considering that the algae contain green organisms and chloroplasts.

Once you grow lettuce using a hydroponic system, be prepared to see the algae developing in the hydroponic systems but do not panic as it does not cause severe damage to plants. You can only worry if the algae buildup becomes severe as your hydroponic lettuce can be deprived of nutrients and oxygen. 

The algae, which can be red, brown, black, bluish, or green depending on the type also cause unbalanced pH levels. Note that you can treat algae after harvesting your hydroponic lettuce.

Algae can be controlled by changing the water for your plant more often and also cleaning the reservoirs and pipes to prevent its development. Do not expose the solution systems and the medium to direct sunlight as it causes the algae to become active.

The affected plant roots can be rinsed to remove the build-up using hydrogen oxide. Therefore, avoiding the buildup is the best way to deal with algae.

– Spider Mites

Spider mites are spider-like pests that are reddish, yellow, or pale green. The spider mites’ nymphs are also found in yellow or pale green color. Spider mites cause damage to the plant by sucking all the sap, thereby causing yellow speckles on the leaves. However, you can also identify their presence by the fine web that may be on the hydroponic lettuce shoots and leaves.

Isolate the affected plants as soon as you notice the spider mites, otherwise, they can spread easily using their web to move from one lettuce plant to another. Treat your hydroponic lettuce with Pyrethrin to paralyze them at all their life cycle stages. This way the spider mites cannot feed and ultimately, they will die.

Spider mites can also be prevented by maintaining the 50 percent humidity level which is not ideal for the pest, which thrives well in dry climatic conditions.

– Whiteflies

Whiteflies are tiny pests that also use their mouthparts to draw the plant chlorophyll. Both the winged adult and wingless nymph feast on plant sap. The honeydew and sooty mold are the signs of whiteflies infection. The whiteflies excrete the sweet fluid called honeydew when they feed and this paves the way to the development of the fungus called the sooty mold.

You can prevent the spread of whiteflies by introducing parasitic wasps that will feed on the nymphs. You can also scrape off the eggs that are on the undersides of the leaves using your hands or a slightly sharpened tool.

Use neem oil spray to kill the whiteflies as it will stop the nymphs from developing into adults and the eggs from hatching into nymphs.

Their life cycle will be disrupted so their reproduction will be stopped. Nonetheless, you can also use yellow sticky traps to catch the adult flies. The whiteflies will be caught on the sticking substance on the yellow cards.

– Thrips

Thrips are tiny black, yellow, or brown sucking pests. The thrips are usually found in congregants on plant leaves, petals, and flowers. Your hydroponic lettuce’s leaves turn dark and brittle once attacked. The adult thrips also lay their eggs in the holes that they form as they pierce into the plant stem and leaves.

To treat thrips, you can use sticky traps as well. You can also use insecticidal soap to dissolve the outer coating of these soft-bodied bugs, thereby destroying it in the process. The fatty acids’ potassium salts are the dissolving agent. 

Note that you should spray the insecticidal soap repeatedly after every ten days to destroy the whiteflies. You can also use your fingernails to scrape off the whiteflies’ eggs.

– Aphids

Aphids are sap-sucking pests as well. These pear-shaped pests are mostly found on weak or stressed plants. Aphids affect every part of the hydroponic lettuce. The pest also leaves honeydew on the plant leaves.

Ants feed on the honeydew that is excreted. Therefore, if you see ants around your hydroponic lettuce, know that your plant is in trouble with the aphids. Insecticidal soap or neem oil are effective interventions for controlling aphids.

– Fungus Gnats

Fungus gnats look like whiteflies. Adult fungus gnats do not cause any damage to your hydroponic lettuce. The larva is the one that is responsible for any damage as it feeds on the plant as well as the algae. The fungus gnats prefer damp, dark, and humid conditions at the base of your hydroponic lettuce.

You can control fungus gnats by freeing the growing system from algae. Also, dry out the medium you are using after feeding and watering your hydroponic lettuce. Fungus gnats are dormant in moisture-free conditions.

Neem oil, pyrethrin, and insecticidal soap can also be used to control pests. You can also capture adult gnats using sticky traps. Neem oil is effective in destroying the pests at any stage of their life cycle.

Hydroponic lettuces in hydroponic pipe


Does Hydroponic Lettuce regrow after a harvest?

Yes, Hydroponic Lettuce has the potential to regrow after harvest. By cutting the lettuce leaves above the crown (base of the plant), new leaves can sprout, allowing for additional harvests. However, the regrowth capacity may vary depending on the specific lettuce variety and growing conditions.

Does Hydroponic Lettuce need to be flushed?

Flushing is not necessary for Hydroponic Lettuce as it grows in a controlled nutrient-rich water system.

When should I stop using grow lights for Hydroponic Lettuce?

You can stop using grow lights for Hydroponic Lettuce once the plants have reached maturity and are ready for harvest.


You have just acquired all the information necessary for you to grow your hydroponic lettuce the right way. Let’s have a quick look at the main points in the summary below.

  • Hydroponic lettuce grows well in a spot with low light where it can receive an average temperature of 68 to 75 degrees Fahrenheit during the day and moderate humidity levels of 60 percent.
  • Hydroponic lettuce matures quickly and can be harvested by removing individual leaves or cutting the whole vegetable head.
  • You can store the lettuce head and not individual leaves in the fridge so that you can use it for an extended period.
  • Always check for pests and diseases on your hydroponic lettuce to avoid losing the crop.
  • Fertilizers should be applied to supplement nutrients like nitrogen, which are needed most by your lettuce.

Now, you are eager to start growing your leafy vegetable hydroponically. Get started now without delay and enjoy the amazing benefits of eating lettuce all year round!

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