How to sow seeds in cotton, pots, or directly in the ground?

In this article 9 ⌄

A sowing rarely fails because of a lack of care. It fails because the wrong method was chosen for the species, the seeds were sown too deeply, or the soil was too cold. These three causes explain the vast majority of failures — and they can be corrected by knowing three rules.

This guide compares the three methods — cotton, pots, and direct sowing — explains which species belongs to which method, and details transplanting, the stage when seedlings you managed to get started are lost.

What a seed needs

Three conditions, and only one is optional.

• Water — it triggers imbibition, which awakens the embryo. Constant moisture: a seed that swells and then dries out dies.
• Warmth — that of the soil, not the air. Each species has its own threshold: 5 °C for a pea, 8–10 °C for a carrot, 18–20 °C for a tomato or basil.
• Oxygen — this is the forgotten factor. Waterlogged or compacted substrate suffocates the seed, causing it to rot instead of germinating.
• Light — optional and variable. Most seeds germinate in darkness; some need it (lettuce, celery, borage) and are therefore sown barely covered.

Sowing on cotton

A piece of cotton, paper towel, or fabric kept damp in a box or saucer.

What it is really for

This is not a cultivation method; it is a method of checking and pre-germination. It has three real uses:

• Germination testing — check an old batch before sowing an entire bed. Ten seeds, two weeks, and you know what to expect.
• Pre-germination — gain a few days with slow or finicky species by sowing the seeds once they have already begun to sprout.
• Educational observation — the bean in a jar remains the most memorable experiment for a child: you can see the radicle, then the stem, then the cotyledons.

The method

1. Moisten the cotton without soaking it — it should be damp, not waterlogged: the seed needs oxygen.
2. Space the seeds apart and cover them with a second light layer.
3. Close the box without sealing it airtight, at around 20°C, away from direct sunlight.
4. Check every two days and re-moisten if necessary.
5. Transfer them as soon as the radicle appears, when it measures 2 to 5 mm.

Sowing in cells

The ideal method for long-cycle species that need to be started under cover to gain several weeks of growing time.

Which species

Tomato, bell pepper, chili pepper, eggplant, cabbage, leek, celery, basil. And optionally: squash, zucchini, cucumber, lettuce — provided they are transplanted while young.

The method

1. Fill with seed-starting compost, press down lightly with your fingertips, and water before sowing: the substrate should be moist and settled.
2. Place 2 to 3 seeds per cell to compensate for failures to germinate. You will thin them out.
3. Cover according to the depth rule below, then press down very lightly — seed-to-soil contact determines water absorption.
4. Mist rather than water, so you do not displace the seeds.
5. Cover with plastic film or a lid until emergence to retain moisture.
6. As soon as the seedlings emerge, remove the cover and reverse the priorities: less heat, as much light as possible.

Thinning

At the stage of the first true leaves, keep the most vigorous seedling per cell. Cut the others with scissors at substrate level rather than pulling them out: this prevents tearing the roots of the one you keep.

Direct sowing in the ground

The default method, and the only possible one for anything that dislikes being disturbed.

Which crops—and why

Carrot, radish, parsnip, turnip, beetroot, lamb’s lettuce, spinach, peas, broad beans, beans. All have a taproot that, once damaged during transplanting, does not regrow: carrots fork and parsnips become misshapen. Sow them in place, without exception.

Row sowing

1. Fine-tune the surface with a rake—a 3 cm clod is enough to prevent a small seed from germinating.
2. Make a straight furrow and water the bottom of the furrow before sowing.
3. Sow thinly—seeds are always sown too densely, which makes thinning laborious and weakens the remaining plants.
4. Close the furrow, firm the soil with the back of the rake, and water with a fine spray.
5. Mark the row with radishes sown in the same furrow: they emerge in three days and prevent you from accidentally weeding out your own seedlings.

Broadcast sowing

For green manures, lamb’s lettuce, and mesclun. Distribute the seeds as evenly as possible, then cover them with one light stroke of a rake. Broadcast sowing that is too sparse fails to provide adequate cover.

Hill sowing

Three to five seeds grouped in one hole for large seeds: squash, beans, corn, peas. Then keep the best plant or plants.

The two rules that determine everything

Depth

Cover with a layer of soil equal to two or three times the seed’s diameter. This is the universal rule, and it explains almost every germination failure.

Seed type	Depth	Examples
Very fine	Barely covered, or on the surface	Lettuce, basil, celery, herbs
Small	5 mm	Tomatoes, cabbage, carrots, radishes
Medium	1 to 2 cm	Beetroot, spinach, Swiss chard
Large	3 to 5 cm	Beans, peas, squash, corn

A seed buried too deeply uses up its reserves before reaching the light. A seed left on the surface dries out between waterings. In summer, sow slightly deeper than in spring—about one and a half times deeper—because the surface dries out faster.

Soil temperature

A thermometer inserted 5 cm into the soil in the morning gives you the answer in ten seconds. This is the mistake made on the first fine weekend in March: the air is mild, the soil is at 8 °C, and the beans rot.

• 5 °C — broad beans, peas, spinach, lamb’s lettuce, radishes
• 8-10 °C — carrot, lettuce, beetroot, onion, cabbage
• 12-15 °C — bean, corn, squash, zucchini
• 18-20 °C — tomato, pepper, eggplant, basil, melon

See The sowing calendar month by month.

Transplanting without losing your plants

This is where successful seedlings are lost.

1. At the right stage — two true leaves for the first transplanting. The rounded cotyledons do not count: they are the seed's reserves.
2. Water beforehand, an hour before handling. A dry root ball crumbles and tears off the fine roots.
3. Hold the plant by a leaf, never by the stem. A damaged leaf can be replaced; a crushed stem is lost.
4. Plant tomatoes deeply — up to the cotyledons. They produce roots along the entire buried stem. This also helps with plants that have already become leggy.
5. Harden off for a week before planting out permanently: take the plants outside for a few hours each day, sheltered from the wind, gradually increasing the time. A plant moved directly from the greenhouse into the open wind loses two weeks.
6. Plant in the evening or in cloudy weather, and water generously to settle the soil around the roots.

Why a sowing fails

Symptom	Likely cause	Correction
No emergence	Soil too cold, seed too deep, or expired batch	Check the temperature, perform a test on cotton before resowing
Uneven emergence	Intermittent moisture, uneven sowing depth	Cover until emergence, refine the surface
Seedlings collapsed at the stem base	Damping-off — a fungus encouraged by cold and excess water	Well-draining substrate, aerate, water less and from below
Long, pale stems	Leggy growth: too warm, not enough light after emergence	Lower the temperature, bring closer to the light, transplant deeper
Seeds displaced, rows with gaps	Watering too heavily	Fine apple pointing upward, or misting
Seeds eaten	Birds, slugs, ants	Cover or netting until emergence

Frequently asked questions

Should you soak seeds before sowing?

Useful for large, thick-coated seeds—peas, broad beans, beans, nasturtiums—a few hours in lukewarm water, no longer: beyond that, they suffocate. Unnecessary and risky for small seeds, which become impossible to handle.

Can you sow directly into potting soil?

It works, but it is less suitable: it is too rich, producing weak seedlings, and its coarse texture makes it difficult for small seeds. Seed-starting mix is inexpensive and makes a noticeable difference.

How long should you wait before becoming concerned?

Allow 3 to 5 days for a radish, 6 to 10 for lettuce, 8 to 15 for a tomato, and up to 3 weeks for parsley or a carrot in cold soil. After twice that time, dig up a seed: if it is soft and decomposed, it has rotted; if intact, it is simply waiting for warmer conditions.

Do some seeds need special treatment?

Yes, dormant seeds: many trees, shrubs, and perennials require a period of cold. See Cold stratification.

Can you sow seeds you have harvested yourself?

Yes, if they come from open-pollinated varieties and have been properly dried and stored. See How to store your seeds from one year to the next.

Key points

To take things further

• The month-by-month sowing calendar
• How to store your seeds from one year to the next
• Cold stratification: why and how to germinate seeds?
• What equipment should you choose to start a natural vegetable garden?

For your first sowings: our vegetable seeds, our spring sowings, and our year-round sowings.