'Sow' Its That Time Again - A Beginners Guide To Seed Sowing
Sowing seeds is one of the most optimistic acts known to humankind. You take something that looks like dust, gravel, or mouse droppings, put it in soil, and confidently expect life to happen. Sometimes it does. Sometimes it really, really doesn’t.
If you’re new to gardening, seed sowing can feel mysterious, intimidating, and strangely like you're a God - yet it can be frustrating when your neighbour’s tomatoes are already six inches tall and yours appear to be… at best imaginary.
Fear not. This guide will walk you through how to sow seeds properly, explain why things work (or don’t), and gently mock the common mistakes we all make - yes even me!.
By the end, you’ll know enough to grow basic plants from seed. And don't forget to watch the videos on types of tray, filling, sowing and covering which you'll find at the end of this blog - enjoy and sorry for having to see my ugly face...
Why Bother Sowing Seeds at All?
Good question. Garden centres sell plants already grown, labelled, and alive - so why start from scratch?
While the process itself is straightforward, success depends on understanding the basic biological needs of seeds and providing suitable growing conditions at each stage.
Here’s why seed sowing is brilliant:
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It’s cheaper – a packet of seeds costs less than a coffee and can produce dozens or sometimes hundreds of plants
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More choice – far more varieties exist as seeds than as ready-grown plants
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It’s weirdly satisfying – watching something grow because of you, is excellent for the soul
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You get better plants – seedlings grown at home can adapt better than pampered shop plants
Also, once you succeed once, you’ll feel like a God.
Understanding Seeds (They’re Not Just Tiny Bits Of Dust)
A seed is basically a plant in pause mode. Inside every seed is:
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A baby plant (the embryo)
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A food supply
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A protective outer coat
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| Begonia seeds and tiny, almost like dust |
When you give it the right conditions - water, warmth, oxygen, and sometimes light/sometimes darkness - it wakes up and gets on with life. You need a mix of all of these to get a seed to germinate.
Important beginner truth:
Seeds don’t need fertiliser to germinate - they already packed lunch. Nutrients are stored within the seed and therefore no fertiliser is needed until the first true leaves develop.
What You Actually Need to Start - Not Much
Let’s strip this back to essentials. Ignore anyone who tells you that you need £200 worth of equipment.
You need:
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Seeds (fresh ones germinate better)
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Containers (seed or plug trays, pots, yoghurt tubs with holes - no judgement)
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Seed compost (not garden soil, not “random dirt”)
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Water
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Light
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A little patience
Optional but helpful:
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Labels (unless you enjoy mystery plants)
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A propagator or clear plastic cover, but not essential for some plants
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A windowsill that isn’t Arctic-level cold
Choosing the Right Seeds (Start Easy)
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| Always follow the instructions - i know but most people don't |
We've all done Cress on some kitchen roll in a tray on the kitchen windowsill and didn't it grow well but try that with some other types of seed and it'll not be the same result. You see some plants don't care who or when they germinate, others are a little more discerning.
Great beginner seeds:
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Lettuce
Carrots
Hardy annuals and bi-annuals
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Radishes
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Peas
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Beans
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Sunflowers
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Calendula
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Tomatoes
Seeds to avoid at first:
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Parsnips (fussy and slow)
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Lavender (tests your patience and faith)
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Anything labelled “challenging” or “for experienced growers”
(They mean it.)
Seed Compost: Why Regular Soil Is a Terrible Idea
Seed compost is fine, light, and low in nutrients. Seed compost is specifically formulated to support germination and early root development.
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| A nicely filled tray |
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Drains badly
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Compacts easily
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Contains pathogens
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Can rot seeds before they sprout
Seed compost:
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Holds moisture without drowning seeds
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Allows roots to grow easily
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Gives seedlings a clean start
Think of it as a nursery, not an all-you-can-eat buffet. Garden soils are unsuitable for germination because they retain excessive moisture, compact easily, and may contain pathogens that harm seedlings.
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| Once sown the trays need covering |
This is where many beginners panic.
The golden rule:
Plant seeds at roughly twice their own size.
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Tiny seeds = barely covered, sometimes not covered at all
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Big seeds = deeper planting
If a seed packet says “surface sow,” it means:
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Place on compost
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Press gently
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Do not bury
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Often needs light to germinate
Yes, seeds can be fussy about lighting. No, they do not explain why. Seeds should be sown thinly to prevent overcrowding, which leads to poor airflow, weak growth, and increased disease risk.
The Actual Sowing Process (Step-by-Step, No Nonsense)
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Fill your container with seed compost
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Firm gently (don’t squash it like bread dough)
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Water before sowing so seeds don’t float away later
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Sow seeds thinly (crowding causes chaos later)
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Cover if required
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Label everything immediately
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Water gently (fine spray only if you water over head or better still water from below)
Place in a suitable environment as required by the instructions on the seed packet
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| Sow thinly and evenly spaced |
Congratulations - you are now officially sowing seeds. You are creating Life....
Watering: Where Most Things Go Wrong
Seeds need moisture, consistent moisture. They do not need swimming lessons.
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| Beans make excellent starter seeds |
Common beginner mistakes:
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Overwatering until compost resembles soup
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Letting compost dry out completely
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Watering with the force of a fire hose
Best practice:
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Keep compost moist, not wet
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Use a spray bottle or watering can with a rose. May be consider watering from the bottom so to avoid disturbing the seeds
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Check daily- especially on sunny windowsills
If in doubt, poke the compost with your finger. Gardeners do this constantly. It’s normal and makes you feel like you know what you're doing.
Light: Seedlings Are Sun Worshippers
Once seeds germinate, they need light immediately.
If they don’t get it, they become:
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Tall
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Thin
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Pale
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Dramatic
This is called leggy growth, and it’s the plant equivalent of shouting “I NEED SUNLIGHT” while falling over.
Tips:
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South-facing windows are ideal
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Rotate trays daily
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Supplement with grow lights if needed
No, a gloomy kitchen corner won’t do.
Temperature: Seeds Like It Mild
Most seeds germinate happily between 15–25°C.
Too cold:
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Seeds sulk
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Germination slows or stops
Too hot:
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Compost dries out
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Seeds can fail altogether and fry
A warm windowsill or indoor room is perfect. Avoid radiators unless you enjoy crispy compost. but you must go by the instruction on the packet - every plant is different.
Germination: The Waiting Game
Some seeds pop up in days. Others take weeks. Some pretend nothing is happening and then surprise you.
During this phase:
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Don’t dig up seeds to “check”
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Don’t move trays constantly
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Don’t assume failure too early
Gardening teaches patience whether you like it or not.
Thinning Seedlings (Yes, You Must)
When seedlings appear, you'll feel proud. But thinning is essential for good strong healthy plants.
Why?
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Crowded plants compete for light and nutrients
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Weak growth leads to poor plants later
How to thin:
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Snip extras at soil level
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Keep the strongest seedlings
you could pot some on if necessary - see below
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Resist emotional attachment
You’re not being cruel. You’re being practical.
Potting On: Giving Plants Their Next Home
Once seedlings have a few real leaves, they need more space.
Steps:
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Lift seedlings gently by the leaves (not stems, never the stems as this is a death nail to most seedlings)
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Move into slightly bigger pots or bigger cell trays
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Use general-purpose compost now
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Water well and return to light
Plants grow better when they’re not fighting their neighbours.
Hardening Off: The Great Outdoors Shock
Indoor seedlings are soft. Outside is… not. So before planting out:
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Gradually expose plants to outdoors over 7–10 days
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Start with sheltered spots
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Bring them in at night initially
Skipping this step leads to floppy, miserable plants and gardener guilt.
Common Beginner Mistakes - We’ve All Done Them and still do..
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Sowing seeds too early - we all do it
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Overwatering - less is often more
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Forgetting labels - a game of guess the plant
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Using old seeds - don't be a skinflint
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Expecting 100% success - never happens
Even experienced gardeners lose seeds. The goal is progress, not perfection. owing seeds successfully depends on providing appropriate compost, moisture, light, and temperature. While results vary between species, following basic principles ensures high germination rates and healthy early growth.
Seed sowing is a foundational gardening skill. With practice and observation, it becomes reliable and repeatable, forming the basis for growing a wide range of plants throughout the year.
Enjoy your gardening and if you have any questions please ask.
Geoff
Who am I?
I'm a horticulturalist with over 40 years experience in the field. From running garden centres and nurseries growing plants for sale to now, well for the last 12 years, running my own gardening business I'm bringing my expertise to those who are interested. I receive no money or reward for my blogs so they're purely my own thoughts, ideas and experience - enjoy.
Blog 22/01/2026 Gardening By Geoff. - horshamgardener.blogspot.com
1. types of tray
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