Growing from Seed: A Beginner’s Guide

1. When your seeds arrive

For specialist seeds with unusual storage needs, ask us before drying or refrigerating them. Storage requirements are different from the cold, moist treatment used to break dormancy.

2. Know your timing: frost dates & zones

Choose an outdoor sowing or planting date suited to the crop and your location. For indoor starts, count backward using that plant’s indoor growing time, allowing time to harden off before transplanting.

1. 1

   Pick your planting date

   Use local crop guidance, soil conditions and the weather.

2. 2

   Work backward

   Allow the indoor growing time recommended for the plant.

3. 3

   Sow & grow

   Raise seedlings with suitable light, moisture and space.

4. 4

   Ease outdoors

   Allow about 1–2 weeks to adjust, then plant when conditions suit.

Outside the U.S., use local seasonal advice. In frost-free, tropical or dry climates, rain and heat may be more useful planning cues than a spring frost date.

3. Start indoors or sow outdoors?

Start indoors

An indoor start gives crops such as tomatoes and peppers more growing time. Choose it when you have the light, space and time to care for seedlings before moving them outside.

See the seven indoor steps →

Sow outdoors

Direct sowing avoids moving young roots. Beans, peas and many root crops are commonly direct-sown. Wait for suitable soil and weather, and keep the seedbed moist as seeds germinate.

See direct-sowing steps →

Some plants suit either method. For trees, slow perennials and specialist seeds, start with the special-seed checks in Part 8.

4. What you’ll need to start indoors

Gather the basics first. Add optional equipment when it suits the seeds and your growing space.

• 

  Pots or cell trays

  Clean containers with drainage holes, plus a tray to catch water.

• 

  Seed-starting mix

  A light, fine mix suited to seedlings, rather than garden soil.

• 

  A clear cover

  A lid or dome can slow drying. Check moisture and ventilate as seedlings emerge.

• 

  Gentle watering

  A watering can or spray that moistens the mix without washing seeds away.

• 

  Plant labels

  Record the plant name and sowing date while you can still tell packets apart.

• 

  A suitable light source

  A grow light can provide consistent light. Assess the light actually reaching the seedlings.

• Optional

  A heat mat

  Useful for seeds that benefit from warmer mix. Monitor the temperature.

• Optional

  A small fan

  Use gentle airflow when needed, and watch for faster drying.

Keep electrical connections away from water and follow the equipment’s safety instructions.

5. Starting seeds indoors, step by step

Step 1

Prepare the pots & mix

Moisten the seed-starting mix, fill clean containers and let excess water drain. Label each batch with its plant name and sowing date.

Step 2

Sow at the right depth

A common rule is about twice the seed’s width. Use this as a starting point when more specific directions are unavailable. Seeds that need light to germinate require suitable light exposure; follow their covering instructions rather than treating all small seeds alike.

Step 3

Manage warmth & moisture

Use the germination temperature suited to the plant. Keep the mix evenly moist and allow drainage. A clear cover can reduce drying; inspect it regularly and ventilate as seedlings emerge.

Step 4

Give sprouts enough light

For many common indoor seedlings, aim for 12–16 hours of suitable light daily, followed by a dark period. A timer makes this easier. Set the fixture at its recommended distance and adjust it as the plants grow.

A bright-looking room or window can still provide too little consistent light. Watch for seedlings stretching toward it.

Step 5

Water, drain & thin

Water gently from above or let the mix absorb water from below, then drain the excess. Check moisture through the root zone, not just at the surface. Thin crowded seedlings to the spacing suited to the crop; snip unwanted seedlings carefully to protect nearby roots.

Step 6

Feed & pot up when needed

Look for several true leaves and check whether the mix already contains fertilizer. Seedlings in an unfertilized mix may benefit from an appropriate dilute feed; use the fertilizer label and crop guidance. Move crowded roots into a slightly larger container and handle seedlings by their rootball, supporting a leaf if needed.

Step 7

Harden off & transplant

Allow about 1–2 weeks to introduce outdoor conditions gradually. Adjust the pace to the crop and weather, then transplant when the plants and conditions are ready.

1. 1

   Start sheltered

   Try short periods in shade, protected from strong wind.

2. 2

   Build exposure

   Add outdoor time and sun gradually as plants adjust.

3. 3

   Respond to weather

   Protect tender plants from cold, strong sun and harsh conditions.

4. 4

   Plant when ready

   Choose suitable conditions, then water the new planting gently.

6. Sowing directly outdoors

1. Prepare the bed. Choose the light and drainage the plant needs. Remove weeds and prepare a workable seedbed.
2. Wait for suitable conditions. Use local crop guidance and soil temperature to choose your sowing window.
3. Sow, label & water. Use the plant’s depth and spacing. Mark the row, then water gently to settle the mix around the seeds.
4. Keep the germination zone moist. Check rain, wind and the soil itself to decide when to water.
5. Thin as plants grow. Give the remaining seedlings room to reach their mature size.

7. Understanding growing terms

Germination

The first growth from a seed. A stated time range assumes suitable conditions.

Cotyledons & true leaves

Cotyledons are the first seed leaves. True leaves appear later and develop the plant’s characteristic shape.

Direct sow

Sow where the plant will grow, instead of raising a transplant.

Hardening off

Gradually adjusting indoor-grown seedlings to outdoor conditions.

Annual, biennial & perennial

An annual completes its life cycle in one growing season, a biennial usually takes two, and a perennial can live for several years. Flowering and fruiting times vary.

Spacing & mature size

The room plants need as they grow. Use the requirements of the actual plant you are growing.

Sun requirements

The light a plant needs. Compare that with your site’s actual sun, including seasonal shade and heat.

8. Slow & special seeds

Before treating a batch, identify the method required for that seed. If the directions are missing, send us the product name so we can help you find the next step.

Growing fruit trees from seed? Seed-grown offspring can differ from a named parent cultivar and may take years to fruit. Ask about the specific seed and expected variability before you buy or sow.

9. Troubleshooting

Start with these checks and keep a note of your sowing date, light, temperature and watering. The same symptom can have more than one cause.

Tall, thin seedlings

Possible cause

Insufficient light is a common reason for seedlings stretching.

What to do

Increase the light. Move the fixture closer within its recommended distance, or move the pots somewhere brighter. For common indoor seedlings, aim for 12–16 hours of suitable light daily, with a dark period.

No seedlings yet?

What to check

• Is it past the expected germination time?
• Was it sown at the recommended depth, including any light requirement?
• Has the mix stayed evenly moist and at the required temperature?
• Does it need cold stratification or scarification? See Part 8.

If the instructions are missing, or it is well past the expected time, email us the product name, sowing date and a photo of your setup. We can review the method and seed condition with you.

Seedlings collapse at the base

Possible causes

Damping-off disease or other damage around the stem and roots.

What to do

Separate affected trays and check drainage, airflow and cleanliness. Remove dead seedlings and use clean containers and fresh mix for a new sowing. Local Extension advice can help identify the cause.

Pale or yellow leaves

Possible causes

Watering, root conditions, nutrition or normal aging of the first seed leaves.

What to do

Check moisture and drainage, then look at the roots and new growth. Review what nutrients the mix contains before feeding. Use an appropriate dilute fertilizer when the seedling’s stage and growing mix call for it.

White growth or tiny flies

Possible causes

Surface growth and small insects can be separate issues, often worth checking alongside excess moisture.

What to do

Inspect closely, check drainage and clear away decaying material. Identify any insect before choosing a treatment. Send a clear close-up if you need help.

Purple-tinged leaves

Possible causes

Temperature, nutrition or the plant’s natural coloring.

What to do

Compare with normal coloring for the plant and check temperature and root conditions. Review the mix and new growth before deciding whether feeding is needed.

Bleached patches after moving outside

Possible cause

A sudden increase in sun exposure.

What to do

Move plants to a sheltered spot with gentler light while you assess the damage. Increase outdoor exposure more gradually and watch how the new leaves develop.

Chewed or missing seedlings

Possible causes

Pests or physical disturbance.

What to do

Inspect around the seedlings and look again at dusk for clues. Identify the visitor, then choose suitable protection, such as a barrier or cover that fits the problem.

10. Beginner questions