Why won’t my seeds grow?

Why Won’t My Seeds Grow?
by Millissa Flanagan
Johnston County Master Gardener

Welcome to 2026!  It’s an exciting time to begin planning what, how and when we will plant our seeds for each season in the upcoming year.

Seeds respond to temperature, light, and moisture, and when even one of these factors is off, seeds may not sprout. Understanding what seeds need, what some seeds require and how the seasons affect their growth will help you grow strong and colorful flowers all year.

What All Seeds Need
Seeds depend on warm soil, steady light and the right balance of moisture. During winter and early spring, indoor soil can stay cooler than expected, which slows germination for many flower seeds. Light is limited in winter, and even sunny windows won’t provide the required amount of light seedlings need. Using a small grow light will help with this by supporting seed germination and keeping seedlings short, strong, and healthy.

Moisture matters year-round. Soil that stays too wet can rot seeds, while soil that dries too quickly prevents sprouting. A light, fluffy seed-starting mix and gentle watering with a spray bottle will help create the air pockets and moisture seeds need. Planting depth also makes a difference. Seeds planted too deeply may never reach the surface, especially tiny flower seeds that should simply be pressed onto the soil surface.

What Some Seeds Need
Some flower seeds need extra steps before they sprout. These methods imitate natural environments that seeds expect outdoors.

Cold Stratification
Some flowers come from climates where winter signals the seed that a new growing season is coming. These seeds will not sprout unless they first experience several weeks of cold. Stratification imitates this.

How it works:
• Seeds are placed in the refrigerator, usually for 4 to 8 weeks
• The cold temperature breaks natural dormancy
• Once moved into warmth, the seed recognizes “spring” and begins to grow

Why seeds need this:
During winter in nature, moisture slowly enters the seed, enzymes activate, and the seed prepares itself to sprout as temperatures rise. Without this cold period, seeds such as lavender, hibiscus and some native wildflowers may stay dormant even under perfect indoor conditions.

Scarification
Some flower seeds have a very tough outer coating that protects them in nature. This seed coat can be so hard that water has trouble entering the seed. Scarification gently weakens the outer shell.

Ways to scarify seeds:
• Lightly rub the seed on sandpaper
• Nick the edge with a nail file
• Roll seeds gently between two pieces of rough material

Why seeds need this:
In nature, these seed coats are worn down by soil, wind or rain. Scarification helps the seed absorb moisture faster so it can begin germinating. Flowers that often benefit include lupine, hardy hibiscus and red roselle.

Seed Presoaking
Presoaking seeds in warm (not hot) water helps soften the outer layer of the seed so moisture can enter more easily.

How it works:
• Seeds are placed in a cup of warm water for 4 to 12 hours
• The seed begins to swell as it absorbs water
• When planted afterward, it often sprouts more quickly and evenly

Why seeds need this:
Soaking imitates a steady rain that softens the seed coat naturally. Many flower seeds sprout better after soaking. Presoaking also helps seeds germinate more quickly during spring and summer when temperatures may fluctuate.

These treatments—stratification, scarification and presoaking—give seeds the signals they need to recognize that conditions are safe for growing.

Review instructions on the seed packets to make sure you know which of these are required for your particular seeds.  It could be one or all!

How Seasons Change Seed Success

Winter (Dec–Feb)
Winter provides low light, cold soil and dry indoor air. Heat mats, humidity domes, and winter sowing in clear containers help create stable conditions.
Flowers that start well in winter include violas, pansies, snapdragons and winter jasmine.

Spring (Mar–May)
Longer days and warming soil make spring one of the easiest times for flower germination.
Flowers that start well in spring include zinnias, marigolds, cosmos, black eyed susan and sunflowers.

Summer (Jun–Aug)
Hot soil can stop some flowers from sprouting. Shade cloth (for our piedmont area, mosquito net works great), early-morning sowing and careful watering help cool the soil.
Flowers that grow well in summer include Mexican sunflower, lantana and moss rose.

Fall (Sep–Nov)
Cooler nights slow germination, but fall is good for starting hardy flowers that enjoy cool weather or that benefit from winter stratification.
Flowers suitable for fall planting include chrysanthemums, asters, and calendula.

With the right warmth, light and care, even the toughest seeds will surprise you. They are simply waiting for the conditions that tell them it is time to grow.

READY, SET..LET’S START BUILDING OUR 2026 SEED GROWTH CALENDAR!

References

NC State Extension. Plant Toolbox. North Carolina State University, Department of Horticultural Science.

NC State Extension. Homegrown: Gardening Resources. North Carolina State University.

NC State Extension. NC Extension Gardener Handbook. North Carolina State University, Department of Horticultural Science.

Clemson Cooperative Extension. HGIC Factsheets, Home & Garden Information Center. Clemson University.

Cluckinfunfarm LLC, Selma NC – hands on experience from a local homestead. Facebook/cluckinfunfarm: Instagram/cluckinfunfarm