Top Reasons Your Seeds Aren’t Sprouting (And How to Fix Them)

Nothing feels worse than spending time, money, and energy sowing seeds just to see them fail. The key to future success is knowing why germination failed so you can improve your technique. This article reviews common germination issues and provides tips to help you prevent them so that you can have a productive season.

7 Reasons Why Seeds Fail to Sprout

Seeds need the right combination of conditions that work together to germinate, and each crop has specific requirements. Seeds can fail to sprout for several reasons: 

1. Poor Seed Quality

2. Incorrect Planting Depth

3. Temperature Issues

4. Watering Problems

5. Soil Conditions

6. Pests and Diseases

7. Ignoring Specific Seed Requirements  

Learn the needs of each crop you’re growing, monitor progress, and adjust as needed. Identifying issues early in the process could save seeds that otherwise may not germinate, causing you to start over. 

1. Poor Seed Quality

Seed quality can be affected by age, improper storage, and the seed’s characteristics.

Expired Seeds 

Seeds become less viable with age. Exposure to light, moisture, and other environmental factors reduces germination rates. Be sure to check the back of your seed package for expiration dates.

Improper Seed Storage

Seeds exposed to moisture can rot. Light exposure can also cause the seeds to lose viability. 

Humidity and temperature swings can also lower storage capabilities. Store seeds in airtight containers in a dry, dark place with 25-35% relative humidity. If seeds need lower temperatures, store them in a refrigerator.

Avoid purchasing seeds from big-box stores. Those seeds are shipped in January. In the receiving area, they are not stored in optimum conditions. They were packaged in the fall of the previous year and could be 4-6 months old by the time they are put on the shelf in spring.

Not sure if your seeds were stored properly? Conduct a germination test. Learn how in this video, How and When to Run a Germination Test / Are Your Seeds Still Good?

Low-Quality Seeds

Not all seeds are created equal! Always buy seeds from a reputable source that provides clear growing instructions and offers support. Read testimonials, look for certifications, and ask about seed treatment and lab test results. 

This 2023 National Library of Medicine study explains the correlation between seed age, viability, genetics, and longevity. 

Using Your Own Seeds?

Saving seeds from one year to the next is a great way to lower costs and propagate your favorites from last year. Be sure to fully dry and properly store your seeds. If you are new to seed saving, read Seed Saving 101. 

Try planting half your own seeds and half purchased seeds of the same variety to compare germination and early growth. If your seeds do as well or better than the purchased ones, congratulations, you stored them properly! 

2. Incorrect Planting Depth

Planting at the correct depth is crucial for seed germination. For most seeds, this is about twice the depth of the broadest part of the seed. 

Too Deep

If the seeds are sown too deep, they will use all their energy to reach the surface, not get the sunlight they need, or rot in the soil. 

Too Shallow

If planted too shallowly, they could dry out or get eaten by critters or pests. 

Planting Seeds at the Correct Depth

A good general rule is to sow seeds two to three times as deep as their diameter at the widest point. Tips for success: 

• Select the right-sized cell tray for your seeds. 

• Before planting, read each seed packet’s recommendations to ensure you follow them. 

• Check for light or darkness requirements. 

• Sprinkle vermiculite over tiny seeds to hold them in place. 

• Bottom water seeds in trays to prevent them from sinking or being washed away, or use a gentle mister. 

Bootstrap tip:  Sow seeds slightly deeper in sandy soil. Sandy soil dries out quicker, but deeper soil retains moisture longer and ensures the seed has the water it needs. 

3. Temperature Issues

Pay close attention to the temperature needed for seeds to break dormancy. Many seed packets tell you to adjust the temperature after germination, which is as simple as removing the tray from the heat mat.  

Too Cold

Seeds won’t get the signal that it’s time to wake up and sprout. 

Too Hot

Excessive heat can cause death before sprouting or kill them soon after. Prolonged heat also increases the risk of fungal growth. 

Ideal Temperature for Sowing Seeds

Follow the recommended temperatures required for germination.  

• Use a soil thermometer to confirm proper temperature (65° to 75°F (18° to 24°C) for most seeds). 

• A seedling heat mat will help maintain consistent warmth. Pay attention to heat-loving seed requirements like tomatoes, which can handle temperatures up to 85°F (26°C). 

• Overhead irrigation and shade cloth will keep seeds planted outdoors safe during extreme temperature fluctuations. 

4. Watering Problems

Watering too little or too much can be damaging to seed germination. 

Overwatering Seeds

• Leads to rot, mold, and surface algae, which may attract pests

• Roots can’t breathe or properly form 

• Can cause fungal growth

• May displace delicate or uncovered seeds

• Failure to sprout

Check soil moisture levels regularly. Gently press a finger into the soil surface. It should be damp, with no water visible when you push down. Water only as needed. 

Underwatering Seeds

Seeds need water to start the germination process. Water initiates chemical reactions that begin seedling emergence. Without it, the seed will stay dormant. If a seed manages to germinate and then receives too little water, it will be stressed, stunted, or die. 

How to Properly Water When Starting Seeds

• Water only when the soil needs it. Water evenly so the soil is moist but never soggy. If it gets soggy, let it dry out slightly before watering again.

• Use a gentle spray bottle or bottom water to avoid washing away delicate seeds, especially uncovered seeds that need consistent humidity. 

• Mesh trays with holes help to drain excess moisture. 

• Use a humidity or blackout dome to keep tiny and uncovered seeds moist between waterings. 

Moisten the seed-starting mix before sowing seeds to provide initial moisture. Soak large, hard seeds to help the water penetrate before sowing. Research the seeds you’re starting so you can provide ideal conditions. 

5. Soil Conditions

Avoid using garden soil that may be compact or contaminated with pathogens. Seeds that manage to germinate in hard soil may have trouble reaching the surface, uptaking water, and thriving.

Instead, use loose, loamy soil that allows oxygen to flow. Light, fluffy soil: 

• Provides good soil aeration 

• Allows roots to form freely

• Allows roots to naturally air-prune in our 72-cell air-pruning cell trays

• Helps drain excess water 

• Gets essential nutrients to young seedlings during development 

Make sure your seed-starting mix contains the proper levels of NPK (nitrogen, potassium, phosphorus) to help your plants sprout cotyledons and reach the next growth stage, whether up-potting or transplanting. 

Using the Right Soil Mix

Use light, well-draining soil or seed-starting mix. Moisten and vigorously loosen the soil before filling seed trays or pots. If your soil blend has large pieces, sift out any big chunks before moistening the soil. 

• Loosen soil before planting to improve aeration.

• Ensure your up-pot soil has balanced nutrients.

• Mix compost and organic matter into garden soil before transplanting into the garden.

Bootstrap Tip:  Don’t want to buy a specific seed starting mix? Try blending half potting soil and half coco coir to get the perfect texture. 

6. Pests and Diseases

Overwatered plants and stagnant air are easy breeding grounds for fungus, mold, and mildew, which attract predators like mice, birds, and insects. These guys will eat your seeds before they sprout. Take swift action if you see gnats, green algae, or soil crust.

Ways to Keep Pests and Diseases at Bay

• Protect seedlings from moths, caterpillars, aphids, and flea beetles with insect netting.

• Use humidity domes during germination indoors. Open the vents to let air flow and prevent disease. 

• Use frost blankets for cold protection outdoors. Secure them so critters or pests can’t enter. 

• Ventilation is your friend! Once seeds have germinated, your seedlings will benefit from a gentle breeze. 

• Use rack fans on your seed starting shelves indoors. 

• Use circulation fans and vents in a high tunnel to ensure proper airflow to prevent mold, mildew, and pests. 

• Select trays and containers with ample drainage holes to avoid soggy, water-logged seedlings. 

• Avoid over-watering. 

If pests remain an issue, choose quick germinating varieties to beat the pressure. 

7. Ignoring Specific Seed Requirements

Before sowing seeds, be aware of any extra steps you need to take to ensure germination. Research individual seed requirements before planting. If necessary, pre-treat seeds using the methods below. 

• For some seeds, this includes scarification, which is nicking or scratching the edge of the outer seed hull. This allows water to penetrate and the seed to germinate more quickly, reducing the chance of the seed rotting. 

• Stratification mimics a cold season (winter) by placing seeds in the fridge or freezer. It is required for many perennial flowers, trees, shrubs, and wildflowers that would experience a cold spell in nature. 

• Soaking overnight helps soften tough seeds like corn, spinach, beans, peas, nasturtium, and lupine. 

Practice patience. If a seed packet says seeds may take up to three weeks to germinate, don’t give up on them after one! A seed may be in physiological or morphological dormancy if it does not germinate under ideal conditions. These will sprout when additional hormonal or maturity requirements are fulfilled.

Bootstrap Tip:  When seed orders arrive in the mail, place seeds requiring stratification in the refrigerator. Note their placement so you don’t forget about them in the spring.

FAQs: Seeds Not Sprouting

How can I test if my seeds are still viable?

Perform a paper towel germination test in these five simple steps:

1. Place ten seeds in a damp paper towel

2. Put the towel inside an airtight container

3. Keep the container in a warm, dark spot

4. Check for germination after a few days

5. The percentage of germinated seeds after a week is the germination rate of the seed batch

Other testing methods include soil planting, flotation test after soaking (not very reliable), stratification, and using indoor seed-starting kits with heat mats, humidity domes, and germination chambers. 

Can I reuse soil where seeds failed to sprout?

If the sprouting failure is unrelated to the soil and no disease is present, you can reuse the potting soil. 

What is the best temperature for germinating specific seeds like tomatoes or peppers?

Germinate heat-loving tomatoes at 65° to 85°F (18° to 29°C) and peppers at 70° to 90°F (21° to 32°C). To maintain ideal conditions, use a heat mat controller and humidity domes. 

Why do seeds sprout but fail to grow beyond the seedling stage?

If seeds germinate but fail to thrive, they may have received improper care. The most common culprits are insufficient:

• Water amounts

• Sunlight

• Nutrients

• Temperature

• Stratification or scarification requirements 

Or, the seeds may be diseased or unviable. 

How do I prevent mold or fungus when starting seeds indoors?

Provide good air circulation, add a fan on an oscillating low setting, and water from the bottom to prevent mold and fungus.

Will soaking seeds in water before planting improve germination rates?

Soaking seeds before sowing benefits crops like:

• Peas

• Squash

• Beans

• Cucumbers

• Beets

• Corn

Soaking softens the tough outer seed layer, making it easier for water to absorb and the sprout to penetrate.

Do planting containers affect seed germination success?

Yes, too large containers can be inconsistently moist and prone to fungal growth. Choose the containers and trays that are the proper size and have ample drainage for the best germination rates. 

Can I use outdoor garden soil to start seeds indoors?

Outdoor soil is not ideal as it is heavier than seed-starting mix and may contain pests, pathogens, or weed seeds. For the best results, purchase a well-draining seed mix or sterile soilless media like coconut coir. 

How long should I wait before declaring that seeds won’t sprout?

If a seed packet indicates that they should germinate in three to seven days, they are likely unviable if you don’t see activity after a week. 

What are the best supplies for beginners trying indoor seed starting for the first time?

Our seed-starter kits and bundles include everything you need to start an indoor seed-starting area at home. Don’t forget the lighting!