Seed Starting, Fact Sheets, Microgreen Fact Sheets

Bottom Watering vs Top Watering for Seedlings and Microgreens

Microgreen Bottom Watering

Understanding the Importance of Watering Techniques in Microgreens and Seedling Starts

Watering is a fundamental aspect of gardening, a critical factor that can make or break the success of your plants. This is particularly true for delicate stages of plant growth, such as microgreens and seedling starts. These early stages of a plant's life are crucial, requiring precise care and attention, with watering being at the forefront. The objective of this article is to delve into the nuances of two prevalent watering techniques – top watering and bottom watering – and to understand their impact on the growth and health of microgreens and seedlings.

Microgreens and seedling starts are often lumped together but have distinct characteristics and requirements. Microgreens are young vegetable greens, typically harvested just after the cotyledon leaves have developed. They are prized for their nutritional value and are used in a variety of culinary applications. Seedling starts, on the other hand, are young plants that have just begun to sprout, and are in the process of developing their first true leaves. These starts are usually transplanted to a larger growing area once they have established a robust root system.

Despite their differences, both microgreens and seedling starts share a common need for meticulous watering practices. The growth stages of these plants are sensitive, and improper watering can lead to a myriad of problems, including disease, stunted growth, or even plant death. Therefore, understanding the right watering technique for each stage of growth is not just beneficial but essential for a successful harvest.

Traditionally, top watering has been the go-to method for many gardeners. This involves watering from above, mimicking natural rainfall. While this method can be effective for some plants, it can also pose risks, particularly for tender seedlings which may be damaged by the force of the water or develop fungal issues due to wet foliage.

An alternative, which has been gaining popularity among growers, is bottom watering. This method involves watering the plants from below, allowing the water to be absorbed upwards through the soil or growing medium. This technique can offer several advantages, including minimising the risk of disease, providing consistent moisture levels, and ensuring that the delicate foliage of young plants remains dry.

Throughout this article, we will explore these two watering methods in depth. We will compare their benefits and drawbacks, understand their applicability at different stages of plant growth, and examine the best practices for both microgreens and seedling starts. By the end, you will have a clearer understanding of how to effectively nurture these young plants, setting the foundation for a thriving garden.

Differentiating Microgreens and Seedling Starts

In the world of gardening, microgreens and seedling starts represent the nascent stages of plant life, each possessing unique characteristics and requirements. This section aims to demystify these early growth phases, highlighting their differences and similarities and underscoring the pivotal role of water in their development.

Microgreens: The Nutrient-Dense Sprouts

Microgreens, the tender, immature shoots of vegetables and herbs, are harvested just after the first true leaves emerge, following the cotyledon stage. These tiny greens, usually around one to three inches tall, are not just a culinary trend but a powerhouse of nutrients. Microgreens can include a variety of species, from lettuce and kale to radish and mustard. They are grown in a controlled environment, often using soil or a soilless medium, and typically see a harvest time ranging from one to three weeks after planting.

The allure of microgreens lies not just in their nutritional value but also in their ease of cultivation and quick harvest time. They require a delicate balance of moisture, light, and temperature to thrive, making the choice of watering method crucial. Over or under-watering can swiftly lead to the demise of these fragile greens.

Seedling Starts: The Foundation of Future Plants

Seedling starts are the early stages of a plant's life, where the seed germinates and begins to grow its first true leaves. These starts are the foundation for the future plant and are often transplanted to gardens or larger containers once they have established a strong root system. This stage is critical, as the young plants are particularly vulnerable to environmental conditions, pests, and diseases.

Seedlings need a stable environment with controlled moisture, light, and temperature. The watering technique during this stage can significantly impact their survival and growth. Incorrect watering can lead to common problems like damping-off, a fungal disease that affects seedlings and can cause root rot or stem collapse.

The Role of Water in Early Plant Growth

For both microgreens and seedling starts, water plays a central role. It facilitates nutrient uptake, supports cellular growth, and maintains plant turgidity. However, the amount, frequency, and method of watering can vary significantly between the two. Microgreens generally require a consistent moisture level to avoid drying out, while seedlings may benefit from slightly drier conditions between waterings to encourage root growth.

Understanding the water requirements of these early stages is not just about keeping the plants alive; it's about setting the stage for healthy, vigorous growth. The following sections will explore the nuances of top and bottom watering methods, providing insights into selecting and applying the right technique for each stage of growth in microgreens and seedling starts. This knowledge is key to nurturing these plants from their most vulnerable stages to robust maturity.

Exploring the Top Watering Method for Microgreens and Seedling Starts

Top watering, a traditional and widely used method in gardening, involves applying water directly onto the soil surface from above, similar to natural rainfall. This section delves into the nuances of top watering, its benefits, and potential drawbacks when used for microgreens and seedling starts.

Understanding Top Watering

Top watering is straightforward – water is poured over the soil surface, allowing it to seep down to the roots. This method can be implemented using a watering can, hose, or even a sprinkler system. It's a method familiar to most gardeners and mimics the natural way plants receive water in the wild. The simplicity and ease of this method make it a popular choice, especially for larger gardens or outdoor plants.

Benefits of Top Watering

The primary advantage of top watering is its natural approach. It provides a thorough soaking of the soil, ensuring that the water reaches deep into the root zone. This method can also be beneficial in washing away accumulated salts from fertilizers, thus preventing potential harm to the plants. Additionally, for seedlings, top watering can help in compacting the soil around the seeds, promoting better seed-to-soil contact and aiding in germination.

Drawbacks and Risks

Despite its benefits, top watering comes with its set of challenges, particularly for delicate plants like microgreens and seedling starts. The primary concern is the potential for physical damage. A strong stream of water can dislodge young plants or bury seeds deeper into the soil, hindering their growth. Moreover, constantly wet foliage from top watering can create a conducive environment for fungal diseases such as mildew or leaf spot. These issues are more pronounced in seedlings, which are highly susceptible to diseases and physical damage.

Seedling starts, in particular, are prone to a fungal condition known as "damping-off," which thrives in moist conditions. Overhead watering can exacerbate this problem by keeping the soil surface consistently wet. For microgreens, the risk lies in uneven water distribution, which can lead to patchy growth.


While top watering is a natural and effective method for many plants, its suitability for microgreens and seedling starts is limited. The method's potential to cause physical damage and create an environment conducive to diseases makes it less ideal for these delicate growth stages. The next sections will explore bottom watering, an alternative method that may offer a more suitable solution for watering these sensitive plants. By understanding the strengths and limitations of each method, gardeners can make informed decisions to ensure the health and vigor of their young plants.

The Bottom Watering Method: Enhancing Growth in Microgreens and Seedlings

In the delicate stages of plant growth, such as with microgreens and seedling starts, the method of watering can greatly influence their development. Bottom watering emerges as an effective alternative to traditional top watering, offering several advantages particularly beneficial for these young plants. This section explores the intricacies of the bottom watering method, its implementation, and its benefits.

What is Bottom Watering?

Bottom watering is a technique where water is supplied from below, allowing the plants to absorb moisture upwards through the soil or growing medium. In this method, water is poured into a tray or container, and the plants, usually in pots or trays with drainage holes, are set in this water. The soil wicks the moisture upwards, directly to the roots, ensuring that the plants receive an even and adequate amount of water.

Setting Up Bottom Watering

To implement bottom watering, one must ensure the presence of a tray or container large enough to accommodate the plant trays or pots. The key is to add just enough water to the bottom tray – usually about half an inch – so that the soil can absorb it without becoming waterlogged. This method requires careful monitoring to ensure that plants receive the right amount of water and to prevent the soil from drying out.

Benefits of Bottom Watering

  1. Reduced Risk of Disease and Physical Damage: Since the foliage remains dry, there’s a significantly lower risk of fungal diseases, which are common in environments with moist leaves. For seedling starts, this method avoids the physical disturbance that top watering can cause.
  2. Consistent Moisture Level: Bottom watering allows for a more consistent and even distribution of moisture throughout the soil, ensuring that all parts of the root system have access to water. This can be particularly beneficial for microgreens, which require a steady moisture level for uniform growth.
  3. Prevention of Over-Watering: By allowing plants to take up only the water they need, bottom watering minimises the risk of over-watering, a common issue with top watering.
  4. Efficiency in Water Use: This method can be more water-efficient, as it reduces evaporation and runoff, ensuring that most of the water is used by the plant.


Bottom watering presents a practical and effective solution for watering microgreens and seedling starts. Its ability to provide consistent moisture directly to the roots, while minimising disease risks and physical damage, makes it an attractive option for gardeners. As we delve further into the specifics of watering techniques for different growth stages and the significance of avoiding common mistakes in bottom watering, it becomes clear how crucial the right watering method is for the successful cultivation of these delicate plants.

Optimising Growth: Tailoring Watering Methods to the Growth Stages of Microgreens and Seedlings

The growth journey of microgreens and seedling starts is nuanced, with each stage presenting unique requirements for optimal development. A critical aspect of this journey is the choice of watering method, which can vary significantly between top and bottom watering. This section aims to dissect how these methods affect microgreens and seedling starts at different growth stages, helping gardeners make informed decisions for the best possible outcomes.

Initial Stages: Germination and Early Growth

In the initial stages of germination and early growth, seeds and seedlings demand consistent moisture to facilitate root development and sprouting. For seedlings, top watering at this stage can be beneficial as it helps in maintaining uniform soil moisture and ensures seed-to-soil contact, critical for germination. However, it's crucial to use a gentle flow to avoid seed displacement or soil erosion.

For microgreens, the situation is slightly different. These tiny plants are more susceptible to damping-off and other fungal diseases, often exacerbated by the moist conditions created by top watering. In this case, bottom watering can be a more suitable choice as it keeps the surface relatively dry and reduces the risk of fungal infections.

Post-Germination: Developing Robustness

As plants move past germination and start to develop true leaves, their water requirements evolve. Seedlings begin to develop a more robust root system, and it's essential to encourage these roots to grow deeper in search of moisture. Here, bottom watering becomes advantageous for both microgreens and seedlings. It encourages roots to grow downwards, creating a stronger and more extensive root system. This method also helps in reducing the frequency of watering as the soil retains moisture for longer periods.

Maturity: Preparing for Transplant or Harvest

As plants reach maturity, whether it's seedlings preparing for transplant or microgreens nearing harvest, watering needs become more precise. For seedlings, it's critical to balance moisture levels to avoid water stress or root rot. Bottom watering allows for this balance, providing moisture without over-saturating the soil.

For microgreens, consistent moisture levels are key to a successful harvest. Bottom watering ensures that these levels are maintained, fostering even growth and preventing dry spots which can lead to inconsistent crop quality.


Choosing the right watering method for microgreens and seedling starts is not a one-size-fits-all decision. It requires an understanding of the specific needs of plants at various growth stages. Top watering, while beneficial in the early stages of seedling growth, may pose risks for microgreens prone to fungal diseases. Bottom watering, on the other hand, offers a more controlled approach to moisture management, beneficial in the later stages of plant growth. By tailoring watering techniques to the specific needs of each growth stage, gardeners can significantly enhance the health and vitality of their plants, ensuring a thriving garden.

Mastering Bottom Watering: Navigating Common Pitfalls for Healthier Microgreens and Seedlings

Bottom watering, though advantageous for the growth of microgreens and seedlings, comes with its own set of challenges. Avoiding common mistakes is crucial for ensuring the health and vigour of these plants. This section highlights key pitfalls in the bottom watering method and offers practical advice to overcome them, enhancing the effectiveness of this technique.

Overfilling the Bottom Tray

One of the most common errors in bottom watering is overfilling the bottom tray. It might seem counterintuitive, but too much water can be detrimental. When trays are overfilled, plants are left sitting in stagnant water. This not only risks root rot but also creates an ideal environment for the growth of anaerobic bacteria and fungi, particularly harmful during the night when the temperature drops and water-borne pathogens thrive.

To avoid this, the key is moderation. Start by filling the tray with about half an inch of water. This allows the soil to absorb moisture without becoming waterlogged. Regularly check the trays, especially in the initial phases, to gauge how quickly the water is absorbed and adjust accordingly.

Judging Moisture Levels Accurately

Accurately assessing the moisture level is critical in bottom watering. Unlike top watering, where the soil surface can easily indicate moisture levels, bottom watering requires a bit more intuition and experience. A common technique used by seasoned gardeners is to judge the moisture level by the weight of the pot or tray. A well-watered pot will feel significantly heavier than a dry one.

For beginners, it's recommended to first saturate the growing medium completely and then observe how the weight changes as the water is absorbed or evaporates. This practice not only helps in understanding the ideal moisture level for your plants but also prevents the reliance on less accurate methods such as visual inspection or finger tests.

Preventing Water-Borne Diseases

Stagnant water in bottom trays can be a breeding ground for water-borne diseases. To mitigate this risk, ensure that the water in the trays does not sit for extended periods. Regularly empty and clean the trays to prevent the buildup of pathogens. Additionally, using a well-draining growing medium can help in preventing water from becoming stagnant.

Dampingoff | Natural Yield


Bottom watering is an effective technique for growing healthy microgreens and seedlings, but it requires precision and attention to detail. By avoiding common mistakes such as overfilling trays and inaccurately judging moisture levels, and by being vigilant about water-borne diseases, gardeners can fully harness the benefits of this method. Understanding and mastering these nuances can lead to a more successful and rewarding gardening experience, fostering robust growth in your plants.

Navigating the Waters: Understanding and Mitigating Water-Borne Bacteria and Fungal Issues in Plant Growth

In the realm of plant cultivation, particularly for sensitive stages like microgreens and seedling starts, understanding the role and risks of water-borne bacteria and fungal issues is crucial. This section explores these risks and offers strategies to mitigate them, ensuring the health and robustness of these delicate plants.

The Hidden Dangers of Water-Borne Bacteria

Water, essential for plant growth, can also be a carrier of various pathogens. Water-borne bacteria thrive in moist, stagnant conditions, often found in improperly managed watering systems. In the context of bottom watering, if trays are overfilled and water is left standing, it creates a perfect breeding ground for these bacteria. The risks are twofold: first, bacteria can directly attack the plant roots, leading to diseases like root rot; second, they can create an unhealthy environment, weakening the plants and making them more susceptible to other diseases and pests.

The danger is especially acute overnight when temperatures drop, slowing down the evaporation of excess water. This stagnant, cool environment is ideal for bacterial growth. Anaerobic bacteria, which thrive in oxygen-depleted environments, can quickly multiply, harming the plants.

Fungal Issues: A Perpetual Threat

Fungal diseases are among the most common and damaging problems in plant cultivation. Conditions conducive to fungal growth, such as high humidity and persistent wetness, are often a byproduct of incorrect watering practices. In top watering, for instance, if foliage remains wet for extended periods, it can lead to the development of fungal diseases like powdery mildew or leaf spot.

For microgreens and seedlings, the threat is even more significant. These young plants have delicate tissues, making them particularly vulnerable to fungal attacks. A common and devastating fungal issue in seedlings is damping-off, which can decimate entire trays of young plants.

Strategies to Mitigate Risks

  1. Proper Water Management: Regularly monitoring and adjusting watering practices is key. For bottom watering, avoid overfilling trays and ensure water doesn't stand for extended periods. In top watering, water early in the day to allow foliage to dry.
  2. Sanitation and Hygiene: Regularly clean and disinfect watering trays and equipment. This simple practice can significantly reduce the risk of pathogen buildup.
  3. Adequate Air Circulation: Good air circulation helps in reducing humidity levels around the plants, making the environment less favourable for fungal growth.
  4. Use of Fungicides (organic/natural is preferred): In some cases, especially where there's a history of fungal issues, the judicious use of fungicides can be beneficial. However, this should be done carefully, considering the delicate nature of microgreens and seedlings.


Understanding the risks associated with water-borne bacteria and fungal issues is fundamental in the successful cultivation of microgreens and seedlings. Through vigilant water management, regular sanitation, adequate air circulation, and, if necessary, the use of fungicides, these risks can be significantly mitigated. Adopting these strategies will not only protect the plants from immediate threats but also strengthen their overall health and resilience, paving the way for a thriving garden.

Balancing Nutrition and Hydration: Integrating Nutrient Solutions in Watering Techniques for Microgreens and Seedlings

The growth and health of microgreens and seedling starts depend not just on water but also on the right balance of nutrients. In this context, the integration of nutrient solutions with watering techniques is a delicate art that requires precision and understanding. This section delves into the nuances of using nutrient solutions in both top and bottom watering methods, ensuring that young plants receive the nourishment they need without compromising their delicate growth.

The Role of Nutrient Solutions

Nutrient solutions are essential in providing plants with the necessary minerals and vitamins that might not be available in sufficient quantities in the soil or growing medium. For microgreens and seedlings, which have limited nutrient reserves, these solutions can boost growth and improve overall plant health. However, the application of these nutrients needs to be carefully managed to avoid over-fertilization, which can lead to nutrient burn or imbalanced growth.

Integrating Nutrients with Top Watering

When using top watering, the addition of nutrient solutions can be relatively straightforward. The solution is mixed with water and applied directly to the soil. This method allows for even distribution of nutrients. However, caution is required to ensure that the nutrient mix does not lead to wet foliage, which can increase the risk of fungal diseases. It is crucial to apply the solution in a way that minimizes contact with the plant’s leaves, especially for tender seedlings.

Advantages of Bottom Watering with Nutrients

Bottom watering offers a unique advantage when it comes to using nutrient solutions. Since the water is absorbed from below, there is no risk of nutrient burn on the foliage, and the distribution of nutrients can be more even and controlled. This method ensures that the delicate growth of microgreens and seedlings is not hampered by direct contact with the nutrient solution. Additionally, bottom watering reduces the risk of washing away the nutrients, allowing for more efficient use of the solution.

Best Practices for Nutrient Application

  1. Concentration and Composition: Ensure that the nutrient solution is correctly diluted and suitable for the specific needs of the plants. Over-concentration can harm young plants.
  2. Regular Monitoring: Keep a close watch on the plant’s response to the nutrient solution. Signs of over-fertilization include yellowing or burning of leaf edges.
  3. Phased Application: Gradually introduce nutrient solutions, especially for seedlings, to avoid shocking the young plants.
  4. pH Balance: Regularly check the pH of the nutrient solution. An improper pH can affect nutrient uptake and plant health.


The integration of nutrient solutions into watering practices is a critical aspect of cultivating healthy microgreens and seedlings. Whether using top or bottom watering, the key lies in the careful management of nutrient concentration and application. By following best practices and closely monitoring plant responses, gardeners can ensure that their young plants receive the optimal balance of water and nutrients, leading to vigorous growth and a successful harvest.

From Theory to Practice: Scenarios that illustrate the importance of mastering watering Microgreens and Seedlings

The theoretical knowledge of watering techniques gains immense value when paired with practical illustrative scenarios. In this section, we delve into some contrived yet commonly observed scenarios that illustrate the effectiveness of different watering methods for microgreens and seedlings. 

Scenario 1: The Microgreen Business

A small-scale commercial microgreen grower faced challenges with inconsistent growth and fungal diseases using top watering. After switching to bottom watering, they reported not only a reduction in disease incidence but also a more uniform crop. The grower noted that bottom watering allowed for better control over the moisture levels, crucial for the dense planting style of microgreens. The case study highlights the importance of moisture control in reducing disease and achieving consistent quality in commercial microgreen cultivation.

Scenario  2: The Community Garden Project

In a community garden, volunteers experimented with both top and bottom watering for seedling starts. They observed that while top watering was initially easier, it led to several instances of damping-off in the seedlings. After transitioning to bottom watering, the garden saw a noticeable decrease in seedling mortality. This case study underscores the significance of choosing the right watering method for the sensitive early stages of plant growth, particularly in a community setting where multiple caretakers are involved.

Scenario 3: The Urban Gardener

An urban gardener shared their experience of growing a variety of seedlings in a small balcony space. Initially using top watering, they encountered issues with uneven growth and overwatering. After switching to bottom watering, they found it easier to manage the water needs of different plants and noticed healthier growth. This example demonstrates the practicality and effectiveness of bottom watering in a constrained urban gardening environment.

Scenario 4: The Organic Hobbyist

A hobbyist gardener specialising in organic produce experimented with adding nutrient solutions in their watering regime. They found that carefully managing the concentration and application of nutrients in bottom watering resulted in healthier, more vigorous seedlings, ready for transplant. This experience highlights the role of nutrients in conjunction with the right watering technique in producing robust organic plants.


These fictional scenarios provide valuable insights into the practical aspects of watering microgreens and seedlings. They demonstrate that while both top and bottom watering have their places, the choice depends on various factors including the plant type, growth stage, and environmental conditions. These real-world experiences serve as a guide for gardeners, helping them make informed decisions to ensure the health and success of their plants.

Watering Wisely: Concluding Thoughts on Microgreens and Seedling Starts

As we conclude our exploration of the watering techniques for microgreens and seedling starts, it's clear that the choice of method – top watering or bottom watering – is not just a matter of preference, but a strategic decision that can significantly influence plant health and growth. This final section summarizes the key insights and offers recommendations for gardeners looking to optimize their watering practices.

Summarizing Key Insights

  1. Understanding Plant Needs: Both microgreens and seedlings have specific requirements at different growth stages. Microgreens thrive with consistent moisture levels, which can be effectively managed through bottom watering. Seedling starts, on the other hand, benefit from a gradual transition from top to bottom watering as they develop.
  2. Balancing Moisture and Disease Prevention: While top watering mimics natural rainfall, it can increase the risk of fungal diseases due to wet foliage. Bottom watering, in contrast, keeps the foliage dry and reduces disease risks but requires careful management to avoid over-saturation and the development of water-borne bacteria.
  3. Nutrient Management: Incorporating nutrient solutions requires a delicate balance. Over-fertilization can harm young plants. Bottom watering offers a safer approach for nutrient integration, especially for sensitive microgreens and seedlings.
  4. Learning from others: Real-life examples underscore the importance of adapting watering techniques to specific environments and plant needs. These stories highlight the success of bottom watering in reducing disease, promoting uniform growth, and managing moisture more efficiently.

Final Recommendations

  1. Start with Understanding: Begin by understanding the specific water needs of your plants at each growth stage. This knowledge is fundamental to choosing the right watering method.
  2. Monitor and Adjust: Regularly monitor the soil moisture and plant health, and be prepared to adjust your watering techniques as needed. Remember, what works for one stage of growth may not be suitable for another.
  3. Prevent Diseases Proactively: Be proactive in preventing diseases. Whether you're using top or bottom watering, ensure that conditions are not conducive to the development of fungal or bacterial issues.
  4. Embrace Experimentation: Don't hesitate to experiment and learn from both successes and failures. Gardening is a journey of continuous learning, and each plant can teach you something new.


Watering is more than just a routine task; it's a critical component of plant care, particularly for delicate stages like microgreens and seedlings. By choosing the right watering method and adapting it to the specific needs of your plants, you can greatly enhance their growth and vitality. Whether you're a novice gardener or an experienced green thumb, the insights from this exploration can serve as a valuable guide in your gardening endeavors, helping you nurture healthy, thriving plants.