All You Need to Know About Hydroponic Lettuce Growing Slowly

Common Mistakes that Make Hydroponic Plants Not Growing

Before discussing why hydroponic lettuce is growing slowly, find out the common mistakes and why hydroponic plants are not growing:

pH level

Incorrect pH levels will cause hydroponic plants don’t thrive. Poor pH level causes all plants to suffer.

Not enough lighting

Lighting is one of the most important hydroponic treatments. So, depending on the type of plant, they will need either full sunlight or a little light.  

Using the wrong fertilizer

Conventional fertilizers are not recommended in hydroponics. However, fertilizers designed for a hydroponic system are recommended.

Poor sanitation

Sanitation can have a huge impact on the health of the entire hydroponic plant. Poor sanitation may spread pests and diseases to plants.

Insufficient airflow

Good airflow and ventilation are essential to keep pests away and plants from deteriorating. 


Overwatering may cause waterlogging. If not treated, it may cause the roots to rot and the plants to die.

The Cause of Hydroponic Lettuce Growing Slowly

When your hydroponic lettuce is growing slowly, treat it immediately. However, first, you need to find out the cause of the problem:

Poor soil condition

Poor soil conditions may include poor soil nutrients, improper pH levels, etc. Therefore, it is important to check the soil condition before planting. 

Lack of sunshine

Lack of light or sunshine makes plants experience slow growth. Adjust the need for sunlight according to your plant type.

Excess or Lack of Water

Too much or too little water is a common cause of plants growing slowly. So, schedule the watering or check the soil before watering.

Nutritional Imbalance

Three nutrients plants need are nitrogen, potassium, and phosphorus. Without these nutrients, plants will experience growth problems.

Pest and disease attack

Pests and plant diseases will cause plants to grow slowly. Pests include insects, caterpillars, and rodents. In contrast, plant diseases are mostly fungi or infections from other plant diseases.

Environmental Factors Affect Hydroponic Lettuce Growing Slowly

Environmental factors also affect hydroponic lettuce growing slowly, including:


Hydroponic lettuce temperature should be between 45-70 degrees Fahrenheit. The warmer temperature during the daytime and cooler at night time. High temperatures in lettuce can cause bolting and affect the bitter taste of lettuce.


Hydroponic lettuce needs up to 18 hours of direct sunlight. For indoor growing, installing LED or fluorescent lights are recommended. Lack of light will result in a pale-colored plant and a lack of growth.


The humidity level for hydroponic lettuce is between 50-70%. Low humidity will cause plants to wither. In comparison, high humidity will cause root absorption of nutrients to decrease. 

Advantages of Hydroponic Lettuce

Lettuce is one of the plants that are usually good for hydroponic cultivation. In addition to having a high economic value and a soft texture, the plant is also highly beneficial for your health.

For example, consuming lettuce can improve skin health and vision since it is rich in Vitamin A and beta-carotene.

However, don’t be discouraged if you already know what causes hydroponic lettuce to grow slowly. It’s time to learn how to grow it properly and know some of the advantages of hydroponic lettuce itself:

  • The cleanliness of the plants being produced is highly guaranteed.
  • Nutrients will be delivered efficiently.
  • It would be a weed-free plant.
  • The possibility of pest attack will be slight.
  • Plant growth is more controlled.
  • Narrow land required.

What Makes Hydroponic Lettuce Growing Rapidly?

Preventing slow hydroponic lettuce growth by paying attention to these five main factors:

Clean Water

Using clean water in hydroponics is recommended. The water must be clean from dirt, trash, pathogens, etc. Use groundwater, well water, and rainwater for the best results. 


Nutrients can be absorbed by plant roots directly through nutrient solutions. Essential nutrients in hydroponic lettuce include calcium, nitrogen, and potassium.

Growing media

A good growing medium helps absorb nutrients and guarantees humidity and good drainage. The selection of growing media should be adjusted to the characteristics of the plant.

Oxygen availability

Oxygen in hydroponic cultivation is essential. Oxygen in the root system promotes faster plant growth. Low oxygen levels cause plants to wither.

Seed quality

Seeds in hydroponic lettuce should be disseminated on trays. So, seeds should have a germination rate of more than 80%, free from pests and diseases.

Step-by-Step for Growing Hydroponic Lettuce

To minimize failure on your hydroponic lettuce growing slowly, make sure you know the right tricks:

Seeding seeds

Seed seeding is done for the seeds to be planted and to grow well using any media. Rockwool, for example, should be moist and punctured. Leave it for at least a day before exposing the seeds to direct sunlight.


The transplantation process should be done at least two weeks after seeding. Or when the seeds already have left. 


Self-care in a hydroponic system is simple. The trick is to add water with nutrients once a day. Also, place the plant in a place that gets enough sunlight. 

Harvesting Process

There is a time provision when harvesting lettuce. Normally, the plant can be harvested when it reaches the age of 30-45 days.

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