Microgreens Fertilizer Needs: Do They Require Extra Nutrient Support

🌱 What Are Microgreens and Why Fertilizer Matters

Microgreens are the tender seedlings of herbs and vegetables harvested just after the cotyledon stage, generally within seven to fourteen days of germination. These diminutive plants have gained popularity because they pack intense flavours, vibrant colours and dense levels of vitamins, minerals and phytochemicals into a tiny package. Home gardeners and commercial growers are attracted to microgreens because they grow quickly in limited space and are highly adaptable to indoor conditions.

A key question for growers is whether these young seedlings benefit from extra fertilizer, since fertilization adds cost and may influence flavour and nutritional profile. Understanding how microgreens derive their nutrients and how different species respond to supplemental feeding helps growers decide when nutrient support is beneficial and when it is unnecessary.

🌿 Do Microgreens Need Fertilizer to Grow?

Most microgreens derive the bulk of their early nutrition from the seed itself, so they usually do not require additional fertilizer to reach harvest. Seeds contain stored carbohydrates, proteins and minerals that sustain the seedling through germination and early growth, and the cotyledons act as photosynthetic organs once they emerge.

Extension guides note that microgreens can be raised successfully with plain water and a good substrate; if fertilizer is used, a dilute solution of around 50–100 ppm nitrogen is sufficient and higher rates are not generally needed (5). The term ppm stands for parts per million, and in this context it means how much nitrogen is dissolved in water. For growers, 100 ppm nitrogen is considered a very light feeding compared to full strength plant fertilizers, which can exceed 200–300 ppm.

Research shows that some species respond to moderate fertilization with slightly higher yields, but excessive nutrient supply can cause lodging, increase nitrate accumulation or reduce desirable antioxidants (15). Lodging refers to plants becoming weak and falling over, which makes harvesting more difficult and reduces quality.

Therefore, most microgreens do not require extra nutrient support, and any supplementation should be modest and tailored to the species and growing conditions.

🔬 Why Microgreens Don’t Need Fertilizer in Early Growth

The limited need for fertilization in microgreens stems from their reliance on seed reserves and the brevity of the growth cycle. Microgreens are harvested so early that they do not reach the stage where nutrient deficiencies typically appear.

Peer-reviewed reviews describe microgreens as crops that use very little land, water or fertilization compared with conventional vegetables because they are harvested at a tiny size (17). The cotyledon leaves supply energy through photosynthesis, while proteins and minerals stored in the seed support early development.

Penn State Extension emphasises that fertilization rates above 100 ppm nitrogen are rarely needed (5). The University of Florida further notes that most microgreen species grow well with no fertilizer at all, though longer growing species may benefit from briefly floating trays in a nutrient solution around 80 ppm nitrogen (6).

Because the crop cycle is so short, high amounts of fertilizer often do not have time to be taken up before harvest. Instead, excess nutrients can accumulate as salts in the growing medium, which can stress seedlings and slow growth.

🌊 Do Purslane Microgreens Need Fertilizer or Nutrients?

Purslane (Portulaca oleracea) is a succulent halophyte, meaning it naturally tolerates salty conditions. This makes it very different from most crops and explains why it performs well with minimal fertilization.

Research shows that purslane can produce strong growth even under limited nitrogen supply, and high fertilization is unnecessary (2). Instead, environmental factors like salinity and light play a larger role.

For example, studies show that moderate salinity levels of 80 mM sodium chloride improved growth. The unit mM stands for millimolar, which describes the concentration of a substance in water. In simple terms, this means a controlled amount of salt was added to the growing environment. Under these conditions, biomass increased by about 21 percent while nitrate and oxalate levels decreased (3).

Another study found that moderate salinity improved pigment levels and nitrogen efficiency, while high salinity reduced growth (4). This shows that purslane benefits from mild stress rather than heavy feeding.

Because purslane seeds are relatively nutrient rich, growers can rely on seed reserves and focus more on lighting and watering rather than fertilizer.

🌻 Do Sunflower and Pea Microgreens Need Fertilizer?

Sunflower microgreens have large seeds packed with proteins and minerals, making them among the least dependent on supplemental feeding.

A controlled study tested multiple nitrogen fertilizers at a concentration of 26.5 mM. This is a measurement of how much nitrogen was dissolved in the solution. Even at this relatively high level, there were no significant differences in fresh weight, dry weight or chlorophyll content compared to plants grown with water only (7).

This clearly shows that sunflower microgreens do not benefit from added fertilizer during their short growth cycle.

Pea microgreens behave similarly because their large cotyledons supply ample nutrients. In one experiment, plants grown with a 10 percent algae solution showed no improvement compared to water (8). The growing medium already contained fertilizer at about 1 kg per cubic meter, meaning it had baseline nutrients available.

Light intensity was measured at 230 µmol m⁻² s⁻¹, which refers to how much light energy reaches the plants. This unit measures photosynthetically active radiation, or the light plants use for growth. The study found that light had a much bigger impact on growth than nutrient supplementation.

🌱 Radish, Beet and Cabbage Microgreens Fertilizer Needs

Radish microgreens illustrate a key trade off between yield and nutritional quality.

When grown with a 50 percent Hoagland nutrient solution, which is a standard plant nutrient mix, radish microgreens produced more biomass and chlorophyll (16). However, plants grown with water had higher levels of antioxidants and lower nitrate levels (16).

This means fertilization can increase size and yield, but may reduce certain beneficial compounds.

Another study showed that radish microgreens can be grown without any substrate using only water in vertical systems, still producing high nutritional value (20). Additional experiments found that fish fertilizer did not improve growth compared to compost based media (19).

For beet and cabbage microgreens, nutrient solutions are often measured in mg L⁻¹, which means milligrams per liter of water. A typical solution might contain 200 mg L⁻¹ nitrogen, 50 mg L⁻¹ phosphorus and 300 mg L⁻¹ potassium (9). These are moderate levels compared to full strength hydroponic feeding.

Even at these levels, improvements are modest. In some cases, reduced nutrient availability increases phytochemicals, meaning slightly stressing the plant can improve nutritional quality.

🥦 Brassica Microgreens Fertilizer Response (Broccoli, Kale, Arugula, Mustard)

Brassicaceae microgreens respond more to fertilization than larger seeded crops, but only up to a point.

Studies show that growth increases up to about 140 mg L⁻¹ nitrogen, after which additional fertilizer provides no benefit (1). This is important because it shows there is a ceiling where more nutrients stop helping.

Other trials used fertilizer levels ranging from 50 to 200 ppm nitrogen. Yield increased significantly, especially for arugula, but plants grown at 200 ppm became weak and prone to falling over (15). This again highlights the balance between growth and structure.

Researchers recommend around 150 ppm nitrogen as an optimal level for these species, providing strong growth without causing instability (15).

Kale microgreens have also been used for biofortification, which means increasing specific nutrients in the plant. In one study, adding selenium at 10 to 40 µM increased selenium content without affecting yield (13). This shows that small amounts of targeted nutrients can enhance nutritional value without changing growth.

🌿 Basil Microgreens Fertilizer Requirements and Nutrient Strategy

Basil microgreens have smaller seeds and longer growth periods, which makes them more responsive to nutrient availability.

In one study, enriched nutrient solutions increased yield by 133 percent under low light conditions (11). However, when nutrients were reduced and light intensity increased, antioxidant levels rose by up to 81 percent (11).

Another study tested nutrient strength from 25 percent to 125 percent of a standard solution. The highest yield occurred at 50 percent strength, while the highest antioxidant levels occurred at 125 percent strength (12).

This demonstrates a clear trade off between yield and nutritional quality. Growers can adjust nutrient levels depending on their goals.

🧑‍🌾 Microgreens Fertilizer Guidelines for Growers

For most microgreens, especially those with large seeds such as sunflower, pea and purslane, additional fertilizer is unnecessary. A clean, well drained growing medium and proper watering are usually enough.

If fertilization is used, keep it light. Around 50 to 100 ppm nitrogen is sufficient for most cases, while 150 ppm can be used for species that respond well to feeding (5, 15). Avoid exceeding 200 ppm, as this can cause weak growth and higher nitrate levels.

In hydroponic systems, quarter strength nutrient solutions are common, which means using about one quarter of a standard fertilizer concentration (9).

Light and environmental conditions often have a greater impact than nutrients. Increasing light intensity or optimizing watering can improve growth more effectively than adding fertilizer.

🌾 Final Conclusion: Do Microgreens Need Extra Nutrient Support?

Microgreens are unique because their entire life cycle is powered largely by the seed itself. Most species grow successfully without added fertilizer, and excessive feeding provides little benefit.

While some microgreens benefit from moderate nutrient supplementation, especially those with smaller seeds, the optimal levels are low. Over fertilizing can reduce quality and create growing issues.

For most growers, the best approach is simple. Focus on strong seeds, good light, and consistent watering. Use fertilizer only when needed and at low concentrations.

📚 Works Cited

1. Shoot Yield and Mineral Nutrient Concentrations of Six Microgreens in the Brassicaceae Family Affected by Fertigation Rate – Horticulturae (2023)https://doi.org/10.3390/horticulturae9050559

2. Agronomical Practices and Management for Commercial Cultivation of Portulaca oleracea – Plants (2023)https://doi.org/10.3390/plants12091756

3. Combined Effect of Salinity and LED Lights on the Yield and Quality of Purslane Microgreens – Horticulturae (2021)https://doi.org/10.3390/horticulturae7060105

4. Growth, Physiology and Nutritional Quality of C4 Halophyte Portulaca oleracea – Plants (2023)https://doi.org/10.3390/plants12081545

5. Growing Microgreens – Penn State Extensionhttps://extension.psu.edu/growing-microgreens

6. Microgreens – University of Florida IFAS Extensionhttps://gardeningsolutions.ifas.ufl.edu/plants/ornamentals/microgreens.html

7. Comparing Sources of Nitrogen Fertilizer on Growth in Sunflower Microgreens – Journal of Food Science and Agricultural Technology (2022)https://doi.org/10.14456/jfsat.2022.6

8. Suitability of Algae Solution in Pea Microgreens Cultivation – Agriculture (2024)https://doi.org/10.3390/agriculture14020162

9. Assessment of Different Growing Media and Nutrient Solutions for Microgreens Production – Plants (2024)https://doi.org/10.3390/plants13010105

10. Commercial Microgreen Production: A Guide for Growers – Virginia Tech Extensionhttps://www.pubs.ext.vt.edu/FP/fp127/fp127.html

11. Modulation of Phytochemical Composition in Basil Microgreens under Different Nutrient Solutions and Light Intensities – Plants (2026)https://doi.org/10.3390/plants15010056

12. Balancing Yield and Antioxidant Capacity in Basil Microgreens – Agriculture (2023)https://doi.org/10.3390/agriculture13081548

13. Selenium Biofortification of Kale Microgreens – Scientia Horticulturae (2024)https://doi.org/10.1016/j.scienta.2023.111480

14. Do Microgreens Respond to Fertilizer Concentration and Substrate Depth? – e-GRO Edible Alert 2024https://e-gro.org/pdf/e906.pdf

15. Environmental and Cultural Practices to Optimize the Growth and Development of Three Microgreen Species – M.S. Thesis, Cornell University (2017)https://ecommons.cornell.edu/handle/1813/57555

16. Effect of Mineral Nutrition on Yield and Nutritional Value of Radish Microgreens under Different Photoperiods – BIO Web of Conferences (2023)https://doi.org/10.1051/bioconf/20236702025

17. Microgreens: Nutritional Properties, Health Benefits, Production Techniques, and Food Safety Risks – PeerJ (2025)https://doi.org/10.7717/peerj.17938

18. Post-Emergent Fertilization and Substrate Effects on Broccoli, Kale, Radish, Cabbage and Mustard Microgreens – Plants (2023)https://doi.org/10.3390/plants12091648

19. Effects of Fertilization and Growing Media on Radish Microgreens – Research Poster, Kwantlen Polytechnic University (2022)https://kpu.ca/sites/default/files/2022-09/Microgreens-poster.pdf

20. Radish Microgreens Produced Without Substrate in a Vertical Multi-Layered System – Frontiers in Plant Science (2023)https://doi.org/10.3389/fpls.2023.1155990

21. Nutritional Quality Profiles of Six Microgreens – Scientific Reports (2025)https://doi.org/10.1038/s41598-025-85860-z