Reading Seed Packets: A Beginner's Decoder Ring

You have picked up a packet of seeds at the nursery, flipped it over, and been greeted by a wall of tiny text, symbols, and instructions that might as well be written in code. Sow depth 6mm. Thin to 30cm. Germination 7 to 14 days. Days to maturity 65 to 80.

What does it all mean? And does any of it actually matter?

Yes, it does. But it is not as complicated as it looks. Let’s decode seed packets so you can plant with confidence.

The Front of the Packet

The front usually shows you:

• Plant name (common and sometimes botanical)
• Variety name (like ‘Roma’ for tomatoes or ‘Bloomsdale’ for spinach)
• A photo (not always true to life, but gives you a general idea)
• Quick tags like “heirloom”, “organic”, or “open pollinated”

Not much to decode here. The real information is on the back.

The Back of the Packet: Line by Line

Sow Depth

This tells you how deep to plant each seed. It is usually measured in millimetres or centimetres.

General rule of thumb: Plant a seed to a depth of roughly 2 to 3 times its diameter. Tiny seeds (lettuce, basil) are sown on the surface or barely covered. Larger seeds (beans, corn, pumpkin) go deeper.

If the packet says “surface sow” or “press lightly into soil”, that means do not bury the seed. Just place it on top and press gently. Some seeds need light to germinate.

Spacing

Two numbers usually appear:

• Plant spacing: How far apart each plant should be in the row (e.g., 30cm)
• Row spacing: How far apart the rows should be (e.g., 50cm)

This matters more than most beginners realise. Crowded plants compete for water, nutrients, and light, and they are more prone to disease. Give them room.

Germination Time

This tells you how many days it typically takes for the seeds to sprout after planting. Common ranges:

• Fast (3 to 7 days): Radish, lettuce, Asian greens
• Medium (7 to 14 days): Tomato, basil, beans, cucumber
• Slow (14 to 28 days): Parsley, carrot, capsicum

If nothing has appeared after the upper end of the germination window, give it a few more days before panicking. Soil temperature, moisture, and seed freshness all affect timing.

Days to Harvest (Days to Maturity)

This is how long from planting (or transplanting) until you can start picking. A tomato might say “70 to 80 days”, meaning roughly 10 to 12 weeks from transplanting to your first ripe fruit.

Note: some packets count from seed sowing, others from transplanting. It varies by company, so factor in an extra few weeks if you are starting from seed indoors.

”Sow Direct” vs “Transplant”

Sow direct means plant the seeds straight into the garden where they will grow. Plants like beans, carrots, radish, and corn prefer this because they do not like their roots being disturbed.

Transplant means you can start seeds in small pots or seed trays and move them to the garden later. Tomatoes, capsicum, eggplant, and most herbs do well with this approach.

Some seeds can go either way. The packet will usually tell you which method works best.

Planting Season

Most Australian seed packets include a planting calendar, often shown as a colour-coded chart by climate zone or state. This is genuinely helpful. It tells you which months are best for sowing in your area.

If the packet uses climate zones, figure out which zone you are in (tropical, subtropical, temperate, cool, or arid) and follow the recommended months.

Seed Count or Weight

Packets list either the number of seeds or the weight of seeds inside. This helps you plan how much you need, though most packets contain more seeds than a single planting requires.

Seed Viability: The Expiry Date

Seeds do not last forever. Most packets have a “packed for” or “sow by” date. As a general guide:

Older seeds still might germinate, just at a lower rate. If in doubt, sow a few extra seeds to compensate.

Australian Seed Companies Worth Knowing

Supporting Australian seed companies means you get varieties suited to our conditions, often grown and tested locally. Here are some great ones:

Mr Fothergill’s: Widely available at Bunnings and nurseries. Good range, reliable quality, clear instructions. A solid choice for beginners.

The Seed Collection: Based in Victoria. Excellent range of heirloom and open-pollinated varieties. Great customer service and helpful growing information on their website.

Eden Seeds / Select Organic: Queensland-based. Specialises in organic and heirloom seeds. Huge variety, and they have been around since the 1980s.

Diggers Club: A membership-based organisation with a focus on heritage and heirloom varieties. They also sell plants, bulbs, and have beautiful display gardens in Victoria.

Green Harvest: Based in Queensland. Organic seeds, garden supplies, and a wealth of information on their website.

Storing Leftover Seeds

Most packets contain more seeds than you need for a single planting. Here is how to store the rest:

1. Fold the packet closed tightly or transfer seeds to a small envelope.
2. Label it with the variety and date.
3. Place in an airtight container (a jar or zip-lock bag works well).
4. Store in a cool, dry, dark place. The fridge is ideal.

Properly stored seeds can last well beyond their printed date. Just sow a few extras to account for reduced germination.

Seed vs Seedling: When to Choose Which

Sometimes it makes more sense to buy seedlings (small plants in punnets) rather than seeds. Here is a quick guide:

Start from seed when:

• You want a specific variety that is hard to find as a seedling
• You are planting crops that do not transplant well (beans, carrots, radish)
• You want to save money (a $4 packet of seeds can produce dozens of plants)
• You enjoy the process and have time

Buy seedlings when:

• You want a head start, especially for slow-growing crops like tomatoes and capsicum
• You missed the ideal sowing window and need to catch up
• You only need a couple of plants (buying a punnet is simpler than sowing a whole packet)
• You are a beginner and want the easiest path to success

There is no right or wrong answer. Most gardeners use a mix of both.

The Bottom Line

Seed packets are not mysterious. Once you know what each piece of information means, they become a handy little instruction manual that fits in your pocket. Pay attention to sow depth, spacing, and timing, buy from quality Australian seed companies, and store your leftovers properly. You will be planting like a pro in no time.